This research was supported by the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 604240, project title "An industrial system enabling the use of a patented, lab-proven materials processing technology for Low Cost forming of Lightweight structures for transportation industries (LoCoLite)."

1. Preparação de Amostras <ol><li> Máquina plana cão-óssea e espécimes cruciformes de material comercial da liga de alumínio 6082 (AA6082) utilizando um cortador de laser e um computador de controlo numérico (CNC), a máquina de trituração (por testes de formabilidade em diferentes caminhos de tensão incluindo tensão uniaxial, plano, e escorrimento equi-biaxial estados). </li><li> Medir a espessura de cada espécime cruciformes e cada espécime cão de osso com um paquímetro três vezes na região calibre central e calcular os valores médios. Assegure-se que a espessura da secção de bitola num espécime cruciforme é de 0,7 ± 0,05 mm e se a espessura do espécime uniaxial é de 1,5 ± 0,1 mm. </li><li> Spray-pintar toda a superfície de topo de um espécime cruciformes usando, uma tinta spray preto resistente ao fogo (capaz de suportar temperaturas de até 1093 ° C). Aguardar até que a tinta seca e, em seguida, por pulverização, os pontos de tinta branca resistentes à chama a partir de comprimento do braço para criar um estocásticopulverização padrão a ser reconhecido pelo sistema CID (ver o exemplo na Figura 1). </li><li> Solda um par de termopares para o centro da superfície de trás (lado oposto à superfície pintada) do espécime. Ligue a outra extremidade do termopar para o sistema da máquina de ensaio uniaxial de controlo de temperatura de feedback para monitorar e controlar a história mudança de temperatura. </li></ol> 2. montagem do aparelho Biaxial Testing <ol><li> Montar todas as partes do aparelho de teste bi-axial, incluindo uma placa de base, um eixo central, de entrada e de saída de placas rotativas, carruagens, uma braçadeira, carris de guia, e hastes de ligação rígidos (o aparelho montado é mostrado na Figura 2). <ol><li> Usando uma vareta de ligação, o par placa rotativa de entrada directamente para a maxila móvel de uma resistência de aquecimento máquina de ensaio de tracção uniaxial, que fornece a força de tracção uniaxial. Acoplar a placa rotativa de entrada para o veio de accionamento central epar este veio de accionamento central para a placa rotativa de saída. </li><li> Certifique-se de que a rotação da placa rotativa de entrada à volta do eixo de rotação roda o veio de accionamento, fazendo assim rodar a placa rotativa de saída ao qual está acoplado em torno do eixo de rotação. </li><li> Numa extremidade, cada par de hastes de ligação rígidos para um dos pontos de ligação sobre a placa rotativa de saída. Par a outra extremidade a uma das carruagens. NOTA: Este irá fazer com que os carrinhos com suportes de amostra a deslizar para trás e para a frente ao longo das calhas de guia com baixo atrito, o qual pode aplicar uma força biaxial para o espécime cruciformes. </li><li> A utilização de parafusos de rosca, prender cada um dos braços do espécime cruciformes para um transporte com um suporte de amostra e uma placa de topo. </li></ol></li><li> Configurar apertos na câmara da máquina de ensaio de tracção uniaxial, como mostrado na Figura 3 (a). Ligue quatro cabos de solda para cada par de apertos, que são feitas de aço inoxidável e cobre, respectively, e, assim, conectar os cabos de solda para o fornecimento de energia elétrica. NOTA: A área condutor dos cabos de soldadura é de 50 mm2 e a corrente nominal é 345 A. <ol><li> Colocar os apertos e o grampo do dispositivo de teste biaxial para dentro das duas maxilas da máquina de ensaio de tracção uniaxial e apertá-los dentro (Figura 3 (a)). </li></ol></li><li> Defina-se o aparelho de ensaio biaxial na câmara da máquina de ensaio de tracção uniaxial, como mostrado na Figura 3 (b). <ol><li> Utilizar dois quadros e aparafusar os parafusos na parte superior e os lados do fundo da placa de base para fixar o aparelho na câmara da máquina de ensaio de tracção uniaxial. </li><li> Colocar a amostra no suporte da amostra na parte superior do aparelho de teste biaxial. </li><li> Ligar cada terminal dos cabos de solda para cada região de fixação do corpo de prova. </li></ol></li></ol> 3. Instalação do sistema de aquecimento e resfriamento <ol><li> firmemente connect cada região de aperto da amostra para a placa de topo de aço inoxidável, que serve como eléctrodo para o aquecimento por resistência. </li><li> Apertar os cabos de soldadura com terminais de anel friso para a placa superior de cada região de aperto. </li><li> Ligação queimado bicos com mangueiras para o sistema de arrefecimento rápido com alto fluxo de alimentação de ar regulada em 8.000 kg / m 2 de pressão para o arrefecimento. </li><li> Use quatro bicos de sopro de ar a partir dos braços do espécime para a região central do espécime. NOTA: Os bicos não são dirigidas para a secção de indicador para arrefecimento para evitar o bloqueio da zona central a partir do ponto de vista da câmara. </li></ol> 4. Configuração do Sistema DIC <ol><li> Ligue a câmera de alta velocidade do sistema DIC com uma micro lente para um computador. Ajustar as taxas de quadros da câmara para 25 fps, 50 fps, e 500 fps a partir do menu de taxas de quadro (para os ensaios com as taxas de deformação de alongamento de 0,01 / s, 0.1 / s e 1 / s, respectivamente). Defina as resoluções de todos os imagos a 1.280 × 1.024 pixels. NOTA: As taxas de fotogramas depende do número de pontos de dados a ser recolhidos; pelo menos 200 pontos de dados podem ser obtidos utilizando as definições acima. </li><li> Usar um projector adicional com uma potência de 300 W para testes em altas taxas de deformação. Apontar o projector directamente na câmara da máquina de ensaio de tracção uniaxial. </li><li> Ajustar a lente de câmara de modo que é paralelo à superfície superior da amostra na câmara e focar a câmara na secção de calibre. </li></ol> 5. Programa Experimental <ol><li> Executar a resistência de aquecimento máquina de ensaio de tração uniaxial, clicando no botão de execução triangular no software de controle. NOTA: Electricidade corre através do material AA6082 e aquece a solução a temperatura de tratamento térmico de 535 ° C 14 a uma taxa de aquecimento de 30 ° C / s. O material é impregnado a 535 ° C durante 1 min, o que é suficiente para a resolução completa de precipitados. Air de sopro a partir do sistema de têmpera é utilizado para temperar o material a uma velocidade de arrefecimento de 15 a um de três temperaturas elevadas designadas 100 ° C / s na gama de 370-510 ° C. </li><li> Esticar o espécime com o aparelho de ensaio biaxial a uma velocidade de deformação constante na gama de 0,01-1 / s e registar a história de deformação premindo manualmente o botão de gatilho ligado à câmara de alta velocidade. NOTA: O deslocamento de entrada da máquina de ensaio uniaxial ao aparelho de ensaio biaxial foi controlado pelo software embutido da máquina de ensaio uniaxial. </li><li> Realizar os testes em diferentes caminhos de tensão constituídos por uniaxial, deformação plana, e estados esticando biaxiais 3, ajustando a configuração do aparelho de ensaio biaxial. <ol><li> Desligue duas bielas opostas para testes uniaxial. Fixe um espécime cão-osso sobre o aparelho de teste biaxial e conectá-lo a cabos de solda, como nos passos 3.1-3.4. Repita os passos 5,1-5,2. </li><li> Fixar duas carruagens oposição à placa de base com parafusos de rosca para restringir a deformação no sentido correspondente para testes sob estado plano de deformação. Grampo um cruciformes espécime no aparelho de ensaio biaxial e ligá-lo aos cabos de soldadura, tal como nos passos 3.1-3.4. Repita os passos 5,1-5,2. </li></ol></li><li> Repita os passos 5.3.1-5.3.2 para cada condição de teste três vezes, utilizando-cão novo osso e espécimes cruciformes. </li></ol> 6. Processamento de Dados <ol><li> Importe todas as imagens gravadas pela câmera de alta velocidade para o software de pós-processamento e siga os passos padrão para análise de dados de acordo com o manual do software. </li><li> Use o padrão ISO 3 para determinar os limites formando clicando no botão Modo de FLC no software. NOTA: Este método já foi integrado no software de processamento de imagem correlação. </li><li> Marcar cada resultado dos limites que formam a várias temperaturass, as taxas de deformação e de deformação caminhos em um diagrama. </li><li> Traçar as curvas de limite de conformação em todas as condições de teste para obter uma FLD de uma liga sob condições de estampagem a quente. </li></ol>

<ol>
	<li>Karbasian, H., Tekkaya, A. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+on+hot+stamping.">A review on hot stamping.</a> J. of Mater. Process. Tech. 210 (15), 2103-2118 (2010).</li><li>Miller, W. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+development+in+aluminium+alloys+for+the+automotive+industry.">Recent development in aluminium alloys for the automotive industry.</a> Mater. Sci. and Eng. 280 (1), 37-49 (2000).</li><li>Shao, Z., Li, N., Lin, J., Dean, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+New+Biaxial+Testing+System+for+Generating+Forming+Limit+Diagrams+for+Sheet+Metals+Under+Hot+Stamping+Conditions.">Development of a New Biaxial Testing System for Generating Forming Limit Diagrams for Sheet Metals Under Hot Stamping Conditions.</a> Exp. Mech. 56 (9), 1-12 (2016).</li><li>Ayres, R. A., Wenner, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strain+and+strain-rate+hardening+effects+in+punch+stretching+of+5182-0+aluminum+at+elevated+temperatures.">Strain and strain-rate hardening effects in punch stretching of 5182-0 aluminum at elevated temperatures.</a> Metall. Trans. A. 10 (1), 41-46 (1979).</li><li>Shao, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+investigation+of+forming+limit+curves+and+deformation+features+in+warm+forming+of+an+aluminium+alloy.">Experimental investigation of forming limit curves and deformation features in warm forming of an aluminium alloy.</a> P. I. Mech. Eng. B-J. Eng. , (2016).</li><li>Marciniak, Z., Kuczynski, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Limit+strains+in+the+processes+of+stretch-forming+sheet+metal.">Limit strains in the processes of stretch-forming sheet metal.</a> Int. J. Mech. Sci. 9 (9), 609-620 (1967).</li><li>Li, D., Ghosh, A. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biaxial+warm+forming+behavior+of+aluminum+sheet+alloys.">Biaxial warm forming behavior of aluminum sheet alloys.</a> J. of Mater. Process. Tech. 145 (3), 281-293 (2004).</li><li>Palumbo, G., Sorgente, D., Tricarico, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+design+of+a+formability+test+in+warm+conditions+for+an+AZ31+magnesium+alloy+avoiding+friction+and+strain+rate+effects.">The design of a formability test in warm conditions for an AZ31 magnesium alloy avoiding friction and strain rate effects.</a> Int. J. Mach. Tool. Manu. 48 (14), 1535-1545 (2008).</li><li>Raghavan, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+technique+to+generate+in-plane+forming+limit+curves+and+selected+applications.">A simple technique to generate in-plane forming limit curves and selected applications.</a> Metall. Mater. Trans. A. 26 (8), 2075-2084 (1995).</li><li>Ragab, A. R., Baudelet, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Forming+limit+curves:+out-of-plane+and+in-plane+stretching.">Forming limit curves: out-of-plane and in-plane stretching.</a> J. Mech. Work. Technol. 6 (4), 267-276 (1982).</li><li>Fan, X. -. b., He, Z. -. b., Zhou, W. -. x., Yuan, S. -. j. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formability+and+strengthening+mechanism+of+solution+treated+Al-Mg-Si+alloy+sheet+under+hot+stamping+conditions.">Formability and strengthening mechanism of solution treated Al-Mg-Si alloy sheet under hot stamping conditions.</a> J. of Mater. Process. Tech. 228, 179-185 (2016).</li><li>Zidane, I., Guines, D., L&#233;otoing, L., Ragneau, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+an+in-plane+biaxial+test+for+forming+limit+curve+(FLC)+characterization+of+metallic+sheets.">Development of an in-plane biaxial test for forming limit curve (FLC) characterization of metallic sheets.</a> Meas. Sci. Technol. 21 (5), 055701 (2010).</li><li>Hannon, A., Tiernan, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+planar+biaxial+tensile+test+systems+for+sheet+metal.">A review of planar biaxial tensile test systems for sheet metal.</a> J. of Mater. Process. Tech. 198 (1-3), 1-13 (2008).</li><li>Garrett, R., Lin, J., Dean, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+investigation+of+the+effects+of+solution+heat+treatment+on+mechanical+properties+for+AA+6xxx+alloys:+experimentation+and+modelling.">An investigation of the effects of solution heat treatment on mechanical properties for AA 6xxx alloys: experimentation and modelling.</a> Int. J. Plasticity. 21 (8), 1640-1657 (2005).</li><li>Milkereit, B., Wanderka, N., Schick, C., Kessler, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous+cooling+precipitation+diagrams+of+Al-Mg-Si+alloys.">Continuous cooling precipitation diagrams of Al-Mg-Si alloys.</a> Mater. Sci. Eng. A. 550, 87-96 (2012).</li><li>Crammond, G., Boyd, S. W., Dulieu-Barton, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Speckle+pattern+quality+assessment+for+digital+image+correlation.">Speckle pattern quality assessment for digital image correlation.</a> Opt. Laser. Eng. 51 (12), 1368-1378 (2013).</li></ol>

The authors have nothing to disclose.

métodos de ensaio de formabilidade convencionais usados ​​para determinar os limites de formação são geralmente aplicáveis ​​apenas à temperatura ambiente. A técnica apresentada pode ser usada para avaliar a formabilidade de metais para aplicações de folha de estampagem a quente através da introdução de um aparelho de ensaio novo biaxial para um aquecimento por resistência máquina de ensaio uniaxial. Este não pode ser realizada utilizando métodos convencionais para aplicações de estampagem a qu...

A indústria automotiva está enfrentando um grande desafio global de reduzir o consumo de combustível e minimizar a poluição ambiental de emissões dos veículos. A redução de peso é benéfico para a melhoria do desempenho de automóveis e pode reduzir o consumo de energia directamente um. Devido à baixa formabilidade de chapas de metal à temperatura ambiente, de estampagem a quente e processos de têmpera die frio (referido como estampagem a quente) 2 são utilizados para melhorar a moldabilidade de ligas e, portanto, para obter componentes de formas complexas em aplicações automóveis. Um diagrama de limite de conformação (FLD) é uma ferramenta útil para avaliar a formabilidade de uma liga 3. Out-of-plano testes, tais como o teste Nakazima 4, 5, e os ensaios no plano, tais como o teste Marciniak 6, 7, 8, umare métodos experimentais convencionais para se obter os flds de metais de folha sob diferentes condições de 9, 10, 11. Uma máquina de ensaio biaxial servo-hidráulica também tem sido utilizado para investigar a formabilidade de ligas à temperatura ambiente, 12, 13. No entanto, nenhum dos métodos acima são aplicáveis ​​para testes de formabilidade em condições de estampagem a quente, uma vez que um processo de arrefecimento antes da formação é necessário juntamente com o controlo das taxas de aquecimento e de arrefecimento. A temperatura de deformação e da taxa de deformação são difíceis de obter com precisão. Portanto, um sistema de teste de formabilidade romance é proposto no presente estudo para determinar experimentalmente os limites formadoras de folhas de metal em condições de estampagem a quente.

<table border="0" cellpadding="0" cellspacing="0" width="923">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">Aluminium Alloy&#160;</td>
			<td style="width:152px;">Smiths Metal</td>
			<td style="width:121px;">6082</td>
			<td style="width:421px;">Specimens machining</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">Laser cutter</td>
			<td style="width:152px;">LVD Ltd</td>
			<td style="width:121px;">HELIUS 25/13</td>
			<td>Laser cutting specimens</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">CNC machine</td>
			<td style="width:152px;">HAAS Automation</td>
			<td style="width:121px;">TM-2CE</td>
			<td>Machine specimens by milling</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">Vernier caliper</td>
			<td style="width:152px;">Mitutoyo</td>
			<td style="width:121px;">575-481</td>
			<td>Thickness measurement</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:229px;">Resistance heating uniaxial testing machine</td>
			<td style="width:152px;">Dynamic System Inc</td>
			<td style="width:121px;">Gleeble 3800</td>
			<td>Thermo-mechanical materials simulator</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">High flow quench system</td>
			<td style="width:152px;">Dynamic System Inc</td>
			<td style="width:121px;">38510</td>
			<td>For air cooling</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">Thermocouples</td>
			<td style="width:152px;">Dynamic System Inc</td>
			<td style="width:121px;">K type</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">Nozzles</td>
			<td style="width:152px;">Indexa</td>
			<td style="width:121px;"></td>
			<td>Nozzle flared 1/4 inch bore</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">Welding cables</td>
			<td style="width:152px;">LAPP Group</td>
			<td style="width:121px;">H01N2-D</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">High-speed camera</td>
			<td style="width:152px;">Photron</td>
			<td style="width:121px;">UX50</td>
			<td>For DIC testing</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">Camera lens</td>
			<td style="width:152px;">Nikon</td>
			<td style="width:121px;">Micro 200mm</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">Lamp</td>
			<td style="width:152px;">Liliput</td>
			<td style="width:121px;">150ce</td>
			<td>300W</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">Laptop</td>
			<td style="width:152px;">HP</td>
			<td style="width:121px;">Campaq 2530p</td>
			<td>For images recording</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:229px;">Biaxial testing apparatus</td>
			<td style="width:152px;">Manufactured independently</td>
			<td style="width:121px;"></td>
			<td style="width:421px;">All parts were designed and machinced by authors for biaxial testing</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">Steel&#160;</td>
			<td style="width:152px;">West Yorkshire Steel</td>
			<td style="width:121px;">H13</td>
			<td style="width:421px;">Mateials of the biaxial testing apparatus</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:229px;">Image correlation processing software</td>
			<td style="width:152px;">GOM</td>
			<td style="width:121px;">ARAMIS</td>
			<td>Non-contact measuring system and data post-pocessing</td>
		</tr>
	</tbody>
</table>

a novel biaxial testing apparatus for the determination of forming limit under hot stamping conditions

A estampagem a quente e processo de têmpera molde frio é cada vez mais utilizado para formar os componentes estruturais em forma de complexos de metais de folha. abordagens experimentais convencionais, tal como para fora do plano e em plano testes, não são aplicáveis ​​para a determinação de formação de limites quando o aquecimento e processos de arrefecimento rápidas são introduzidas antes da formação para os ensaios efectuados sob condições de estampagem a quente. Um sistema de teste biaxial novo no plano foi concebido e utilizado para a determinação de formação de limites de chapas metálicas em vários caminhos de deformação, temperaturas e taxas de deformação após o aquecimento e arrefecimento em processos de um aquecimento por resistência máquina de ensaio uniaxial. A parte de núcleo do sistema de teste biaxial é um aparelho biaxial, o qual transfere uma força uniaxial fornecida pela máquina de ensaio uniaxial a uma força biaxial. Um tipo de espécime cruciformes foi concebido e verificada para o teste de conformabilidade da liga de alumínio 6082 utilizando o sistema de teste biaxial proposto. O im digitaissistema idade correlação (DIC) com uma câmara de alta velocidade foi utilizada para a tomada de medidas de deformação de um espécime durante uma deformação. O objectivo de propor esta biaxial sistema de teste consiste em permitir que os limites que formam de uma liga para ser determinada a diferentes temperaturas e taxas de deformação sob condições de estampagem a quente.

Desde flds são altamente estirpe dependente de caminho, a linearidade do percurso de tensão para cada condição de teste foi verificada por análise dos resultados de DIC; os caminhos de tensão são proporcionais ao longo de deformação para cada condição de teste. O intervalo da proporção menor estirpe-para-principal é aproximadamente -0,37 (condição uniaxial) a 0,26 (perto condição biaxial). Mediante o processamento de dados para diferentes condições AA6082, formando da...

Watch this Scientific Journal Video about A Novel Biaxial Testing Apparatus for the Determination of Forming Limit under Hot Stamping Conditions at JoVE.com

A Novel Biaxial Testing Apparatus for the Determination of Forming Limit under Hot Stamping Conditions

Este protocolo propõe um novo sistema de teste biaxial usado em um aquecimento por resistência à tracção uniaxial máquina de teste, a fim de determinar a formação de diagrama limite (FLD) de chapas de metal, sob condições de estampagem a quente.

Um novo aparelho Biaxial Teste para a Determinação do limite de conformação sob Hot Stamping Condições

The hot stamping and cold die quenching process is increasingly used to form complex shaped structural components of sheet metals. Conventional ...

a-novel-biaxial-testing-apparatus-for-determination-forming-limit

Research

Education

JoVE Core

JoVE Journal

Mechanical Engineering

Engineering

Unit 1

Bending

SCIENTISTS IN ACTION

7.5K visualizações.  Imperial College London.  Este protocolo propõe um novo sistema de teste biaxial usado em um aquecimento por resistência à tracção uniaxial máquina de teste, a fim de determinar a formação de diagrama limite (FLD) de chapas de metal, sob condições de estampagem a quente. 

Vídeo: A Novel Biaxial Testing Apparatus for the Determination of Forming Limit under Hot Stamping Conditions

Fabrication of VB2/Air Cells for Electrochemical Testing

A technique to investigate the properties and performance of new multi-electron metal/air battery systems is proposed and presented. A method for synthesizing nanoscopic VB2 is presented as well as step-by-step procedure for applying a zirconium oxide coating to the VB2 particles for stabilization upon discharge. The process for disassembling existing zinc/air cells is shown, in addition construction of the new working electrode to replace the conventional zinc/air cell anode with a the nanoscopic VB2 anode. Finally, discharge of the completed VB2/air battery is reported. We show that using the zinc/air cell as a test bed is useful to provide a consistent configuration to study the performance of the high-energy high capacity nanoscopic VB2 anode.

Fabrication of VB2/Air Cells for Electrochemical Testing

A protocol is presented to study multi-electron metal/air battery systems by using previous technology developed for the zinc/air cell. Electrochemical testing is then performed on fabricated batteries to evaluate performance.

Fabricação de VB<sub&gt; 2</sub&gt; / Ar Células para Electrochemical Teste

A technique to investigate the properties and performance of new multi-electron metal/air battery systems is proposed and presented. A method for ...

Engenharia

High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extreme Conditions

Nuclear Magnetic Resonance (NMR) is one of the most important techniques for the study of condensed matter systems, their chemical structure, and their electronic properties. The application of high pressure enables one to synthesize new materials, but the response of known materials to high pressure is a very useful tool for studying their electronic structure and developing theories. For example, high-pressure synthesis might be at the origin of life; and understanding the behavior of small molecules under extreme pressure will tell us more about fundamental processes in our universe. It is no wonder that there has always been great interest in having NMR available at high pressures. Unfortunately, the desired pressures are often well into the Giga-Pascal (GPa) range and require special anvil cell devices where only very small, secluded volumes are available. This has restricted the use of NMR almost entirely in the past, and only recently, a new approach to high-sensitivity GPa NMR, which has a resonating micro-coil inside the sample chamber, was put forward. This approach enables us to achieve high sensitivity with experiments that bring the power of NMR to Giga-Pascal pressure condensed matter research. First applications, the detection of a topological electronic transition in ordinary aluminum metal and the closing of the pseudo-gap in high-temperature superconductivity, show the power of such an approach. Meanwhile, the range of achievable pressures was increased tremendously with a new generation of anvil cells (up to 10.1 GPa), that fit standard-bore NMR magnets. This approach might become a new, important tool for the investigation of many condensed matter systems, in chemistry, geochemistry, and in physics, since we can now watch structural changes with the eyes of a very versatile probe.

Nuclear magnetic resonance is one of the most important spectroscopic tools. Here, the development of a new approach under high pressure, currently up to 10.1 GPa, is presented. This opens a new window into condensed matter physics and chemistry, where high-pressure research is of great importance.

Alta Sensibilidade de Ressonância Magnética Nuclear em Giga-Pascal Pressões: uma nova ferramenta para sondar propriedades eletrônicas e químicas da Matéria Condensada sob condições extremas

Nuclear Magnetic Resonance (NMR) is one of the most important techniques for the study of condensed matter systems, their chemical structure, and their ...

A Testing Platform for Durability Studies of Polymers and Fiber-reinforced Polymer Composites under Concurrent Hygrothermo-mechanical Stimuli

The durability of polymers and fiber-reinforced polymer composites under service condition is a critical aspect to be addressed for their robust designs and condition-based maintenance. These materials are adopted in a wide range of engineering applications, from aircraft and ship structures, to bridges, wind turbine blades, biomaterials and biomedical implants. Polymers are viscoelastic materials, and their response may be highly nonlinear and thus make it challenging to predict and monitor their in-service performance. The laboratory-scale testing platform presented herein assists the investigation of the influence of concurrent mechanical loadings and environmental conditions on these materials. The platform was designed to be low-cost and user-friendly. Its chemically resistant materials make the platform adaptable to studies of chemical degradation due to in-service exposure to fluids. An example of experiment was conducted at RT on closed-cell polyurethane foam samples loaded with a weight corresponding to ~50% of their ultimate static and dry load. Results show that the testing apparatus is appropriate for these studies. Results also highlight the larger vulnerability of the polymer under concurrent loading, based on the higher mid-point displacements and lower residual failure loads. Recommendations are made for additional improvements to the testing apparatus.

The durability of polymers and fiber-reinforced polymer composites in service is a critical aspect for their designs and condition-based maintenance. We present a novel low-cost laboratory testing platform for the investigation of the influence of concurrent mechanical and environmental loadings, and may help design more efficient yet safer composite structures.

A Plataforma de testes de durabilidade Estudos de Polímeros e reforçado com fibra de polímero Composites, sob estímulo Concurrent Hygrothermo-mecânico

The durability of polymers and fiber-reinforced polymer composites under service condition is a critical aspect to be addressed for their robust designs ...

Detection and Recovery of Palladium, Gold and Cobalt Metals from the Urban Mine Using Novel Sensors/Adsorbents Designated with Nanoscale Wagon-wheel-shaped Pores

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in industrialized countries. Here, the development of optical mesosensors/adsorbents (MSAs) for efficient recognition and selective recovery of Pd(II), Au(III), and Co(II) from urban mine was achieved. A simple, general method for preparing MSAs based on using high-order mesoporous monolithic scaffolds was described. Hierarchical cubic Ia3d wagon-wheel-shaped MSAs were fabricated by anchoring chelating agents (colorants) into three-dimensional pores and micrometric particle surfaces of the mesoporous monolithic scaffolds. Findings show, for the first time, evidence of controlled optical recognition of Pd(II), Au(III), and Co(II) ions and a highly selective system for recovery of Pd(II) ions (up to ~95%) in ores and industrial wastes. Furthermore, the controlled assessment processes described herein involve evaluation of intrinsic properties (e.g., visual signal change, long-term stability, adsorption efficiency, extraordinary sensitivity, selectivity, and reusability); thus, expensive, sophisticated instruments are not required. Results show evidence that MSAs will attract worldwide attention as a promising technological means of recovering and recycling palladium, gold and cobalt metals.

Because of the importance and extensive use of palladium, gold and cobalt metals in high-technology equipment, their recovery and recycling constitute an important industrial challenge. The metal recovery system described herein is a simple, low-cost means for the effective detection, removal, and recovery of these metals from the urban mine.

Detecção e recuperação de paládio, do ouro e cobalto Metais da Mina Urbana Usando novos sensores / adsorventes Designados com poros em nanoescala em forma de roda de carroça

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in ...

Development of an Experimental Setup for the Measurement of the Coefficient of Restitution under Vacuum Conditions

The Discrete Element Method is used for the simulation of particulate systems to describe and analyze them, to predict and afterwards optimize their behavior for single stages of a process or even an entire process. For the simulation with occurring particle-particle and particle-wall contacts, the value of the coefficient of restitution is required. It can be determined experimentally. The coefficient of restitution depends on several parameters like the impact velocity. Especially for fine particles the impact velocity depends on the air pressure and under atmospheric pressure high impact velocities cannot be reached. For this, a new experimental setup for free-fall tests under vacuum conditions is developed. The coefficient of restitution is determined with the impact and rebound velocity which are detected by a high-speed camera. To not hinder the view, the vacuum chamber is made of glass. Also a new release mechanism to drop one single particle under vacuum conditions is constructed. Due to that, all properties of the particle can be characterized beforehand.

The coefficient of restitution is a parameter that describes the loss of kinetic energy during collision. Here, a free-fall setup under vacuum conditions is developed to be able to determine the coefficient of restitution parameter for particles in micrometer range with high impact velocities.

Desenvolvimento de uma instalação experimental para a medição do coeficiente de restituição sob condições de vácuo

The Discrete Element Method is used for the simulation of particulate systems to describe and analyze them, to predict and afterwards optimize their ...

Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film synthesis) for the purpose of exploratory materials research. Certain materials pose a challenge wherein the traditional bulk Hall bar device fabrication method is insufficient to produce a measureable device for sample transport measurement, principally because the single crystal size is too small to attach wire leads to the sample in a Hall bar configuration. This can be, for example, because the first batch of a new material synthesized yields very small single crystals or because flakes of samples of one to very few monolayers are desired. In order to enable rapid characterization of materials that may be carried out in parallel with improvements to their growth methodology, a method of device fabrication for very small samples has been devised to permit the characterization of novel materials as soon as a preliminary batch has been produced. A slight variation of this methodology is applicable to producing devices using exfoliated samples of two-dimensional materials such as graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (TMDs), as well as multilayer heterostructures of such materials. Here we present detailed protocols for the experimental device fabrication of fragments and flakes of novel materials with micron-sized dimensions onto substrate and subsequent measurement in a commercial superconducting magnet, dry helium close-cycle cryostat magnetotransport system at temperatures down to 0.300 K and magnetic fields up to 12 T.

We describe the methodology of mechanical exfoliation and deposition of flakes of novel materials with micron-sized dimensions onto substrate, fabrication of experimental device structures for transport experimentation, and the magnetotransport measurement in a dry helium close-cycle cryostat at temperatures down to 0.300 K and magnetic fields up to 12 T.

Métodos experimentais avançados para baixa temperatura Magnetotransporte Medição de novos materiais

Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film ...

Spark Plasma Sintering Apparatus Used for the Formation of Strontium Titanate Bicrystals

A spark plasma sintering apparatus was used as a novel method for diffusion bonding of two single crystals of strontium titanate to form bicrystals with one twist grain boundary. This apparatus utilizes high uniaxial pressure and a pulsed direct current for rapid consolidation of material. Diffusion bonding of strontium titanate bicrystals without fracture, in a spark plasma sintering apparatus, is possible at high pressures due to the unusual temperature dependent plasticity behavior of strontium titanate. We demonstrate a method for the successful formation of bicrystals at accelerated time scales and lower temperatures in a spark plasma sintering apparatus compared to bicrystals formed by conventional diffusion bonding parameters. Bond quality was verified by scanning electron microscopy. A clean and atomically abrupt interface containing no secondary phases was observed using transmission electron microscopy techniques. Local changes in bonding across the boundary was characterized by simultaneous scanning transmission electron microscopy and spatially resolved electron energy-loss spectroscopy.

A viable technique for the formation of strontium titanate bicrystals at high pressure and fast heating rate via the spark plasma sintering apparatus is developed.

Faísca Plasma Sintering aparelho utilizado para a Formação de titanato de estrôncio Bicrystals

A spark plasma sintering apparatus was used as a novel method for diffusion bonding of two single crystals of strontium titanate to form bicrystals with ...

In Situ Visualization of the Phase Behavior of Oil Samples Under Refinery Process Conditions

To help address production issues in refineries caused by the fouling of process units and lines, we have developed a setup as well as a method to visualize the behavior of petroleum samples under process conditions. The experimental setup relies on a custom-built micro-reactor fitted with a sapphire window at the bottom, which is placed over the objective of an inverted microscope equipped with a cross-polarizer module. Using reflection microscopy enables the visualization of opaque samples, such as petroleum vacuum residues, or asphaltenes. The combination of the sapphire window from the micro-reactor with the cross-polarizer module of the microscope on the light path allows high-contrast imaging of isotropic and anisotropic media. While observations are carried out, the micro-reactor can be heated to the temperature range of cracking reactions (up to 450 &#176;C), can be subjected to H2 pressure relevant to hydroconversion reactions (up to 16 MPa), and can stir the sample by magnetic coupling. 
Observations are typically carried out by taking snapshots of the sample under cross-polarized light at regular time intervals. Image analyses may not only provide information on the temperature, pressure, and reactive conditions yielding phase separation, but may also give an estimate of the evolution of the chemical (absorption/reflection spectra) and physical (refractive index) properties of the sample before the onset of phase separation.

In Situ Visualization of the Phase Behavior of Oil Samples Under Refinery Process Conditions

This article describes a setup and method for the in situ visualization of oil samples under a variety of temperature and pressure conditions that aim to emulate refining and upgrading processes. It is primarily used for studying isotropic and anisotropic media involved in the fouling behavior of petroleum feeds.

In Situ Visualização do comportamento da fase de Amostras de óleo sob Refinaria Condições do Processo

To help address production issues in refineries caused by the fouling of process units and lines, we have developed a setup as well as a method to ...

Subsurface Defect Localization by Structured Heating Using Laser Projected Photothermal Thermography

The presented method is used to locate subsurface defects oriented perpendicularly to the surface. To achieve this, we create destructively interfering thermal wave fields that are disturbed by the defect. This effect is measured and used to locate the defect. We form the destructively interfering wave fields by using a modified projector. The original light engine of the projector is replaced with a fiber-coupled high-power diode laser. Its beam is shaped and aligned to the projector&#39;s spatial light modulator and optimized for optimal optical throughput and homogeneous projection by first characterizing the beam profile, and, second, correcting it mechanically and numerically. A high-performance infrared (IR) camera is set up according to the tight geometrical situation (including corrections of the geometrical image distortions) and the requirement to detect weak temperature oscillations at the sample surface. Data acquisition can be performed once a synchronization between the individual thermal wave field sources, the scanning stage, and the IR camera is established by using a dedicated experimental setup which needs to be tuned to the specific material being investigated. During data post-processing, the relevant information on the presence of a defect below the surface of the sample is extracted. It is retrieved from the oscillating part of the acquired thermal radiation coming from the so-called depletion line of the sample surface. The exact location of the defect is deduced from the analysis of the spatial-temporal shape of these oscillations in a final step. The method is reference-free and very sensitive to changes within the thermal wave field. So far, the method has been tested with steel samples but is applicable to different materials as well, in particular to temperature sensitive materials.

This method aims at locating vertical subsurface defects. Here, we couple a laser with a spatial light modulator and trigger its video input to heat a sample surface deterministically with two anti-phased modulated lines while acquiring highly resolved thermal images. The defect position is retrieved from evaluating thermal wave interference minima.

Localização de Defeitos Subsuperficiais por Aquecimento Estruturado usando a Termografia Fototérmica Projetada a Laser

The presented method is used to locate subsurface defects oriented perpendicularly to the surface. To achieve this, we create destructively interfering ...

Ultrasonic Fatigue Testing in the Tension-Compression Mode

Ultrasonic fatigue testing is one of a few methods which allow investigating fatigue properties in the ultra-high cycle region. The method is based on exposing the specimen to longitudinal vibrations on its resonance frequency close to 20 kHz. With use of this method, it is possible to significantly decrease the time required for the test, when compared to conventional testing devices usually working at frequencies under 200 Hz. It is also used to simulate loading of material during operation in high speed conditions, such as those experienced by components of jet engines or car turbo pumps. It is necessary to operate only in the high and ultra-high cycle region, due to the possibility of extremely high deformation rates, which can have a significant influence on the test results. Specimen shape and dimensions have to be carefully selected and calculated to fulfill the resonance condition of the ultrasonic system; thus, it is not possible to test the full components or specimens of arbitrary shape. Before each test, it is necessary to harmonize the specimen with the frequency of the ultrasonic system to compensate for deviations of the real shape from the ideal one. It is not possible to run a test until a total fracture of the specimen, since the test is automatically terminated after initiation and propagation of the crack to a certain length, when the stiffness of the system changes enough to shift the system out of the resonance frequency. This manuscript describes the process of evaluation of materials' fatigue properties at high-frequency ultrasonic fatigue loading with use of mechanical resonance at a frequency close to 20 kHz. The protocol includes a detailed description of all steps required for a correct test, including specimen design, stress calculation, harmonizing with the resonance frequency, performing the test, and final static fracture.

A protocol for ultrasonic fatigue testing in the high and ultra-high cycle region in axial tension-compression loading mode.

Fadiga ultra-sônico de teste no modo de tensão-compressão

Ultrasonic fatigue testing is one of a few methods which allow investigating fatigue properties in the ultra-high cycle region. The method is based on ...