저자는 설계 및 테스트 셋업을 제조 그들의 도움을 운명 가르시아, 세레나 페라로, 에릭 Quiroz 스티븐 컨 (고급 복합 연구, 엔지니어링 및 과학 실험실을) 감사합니다. 숀 말론, 마이클 Akahori, 데이비드 Kehlet (공학 제조 연구소)는 자신의 제안과 가공 과정에서 도움을 인정합니다. 국립 과학 재단 (National Science Foundation)의 지원 (협력 기금 CMMI-1265691와 REU 보충) 및 A. Muliana, 텍사스 &amp; M 대학 (연구 책임자)에의 Office of Naval Research (N00014-13-1-0604 및 V. 라 Saponara ) 프로그램 디렉터 Yapa 라자 팍세에서 관리 감사 감사합니다.

1. 표본로드 <ol><li> (그림 4) 탱크의 뚜껑을 올리고 측면 지원에를 휴식. </li><li> U 볼트의 표본을 놓고 크로스바 시편의 중심에 접촉되어 있는지 확인합니다. </li><li> 뚜껑에 매달려 알루미늄 지원에 시편의 끝을 휴식. 시편의 끝은 돌출 5-10 mm로해야한다. </li><li> 반복 테스트 할 표본의 모든 1.2-1.4 단계를 반복합니다. </li><li> 뚜껑이 지원 제거 낮은 뚜껑, 뚜껑이 탱크의 입술에 장착되어 있는지 확인합니다. </li><li> 다음 외부 풀리 강철 막대에 무게를 추가하여 원하는 힘을 적용합니다. </li></ol> 2. 측정 변위 <ol><li> 문자열 전위차계 라인이 팽팽하게 고정해야합니다. </li><li> 디지털 멀티 미터를 사용하여, 핀 3 핀 1에 검은 색과 빨간색으로, 전위차계의 외부 핀 (그림 3)에서 저항을 측정그리고 그 값을 기록한다. </li><li> 보정 계수 (이 경우에는 1 kΩ의이 64.895 mm 변위에 대응) 연산함으로써 판독 변위에 저항 판독 변환. </li><li> 반복 각 표본에 대한 2.1-2.3 단계를 반복합니다. </li></ol> 3. 표본 무게 <ol><li> 계량 절차를 시작하기 전에, 변위 데이터를 기록하고는 ASTM D5229 (31), 또는 해당 시험 표준에 따라, 실온에서 시험 유체로 채워진 중간 지주 챔버를 준비합니다. </li><li> 강철 케이블의 끝에서 슬롯 무게를 제거합니다. </li><li> 탱크의 뚜껑을 올리고 측면 지원에를 휴식. </li><li> 시편을 제거하고 준비된 중간 지주 챔버에 배치합니다. 시편 모두에 대해이 단계를 반복합니다. </li><li> 표본을 제거하고 개별적으로 과량의 유체를 제거하기 위해 마이크로 마포를 사용하여 건조. </li><li> 고정밀 규모에 시료를 배치하고, 데이터를 기록 Reading. </li><li> 반복하여 모든 표본에 대한 3.5-3.6 단계를 다음 프로토콜 1 단계를 따르십시오. </li></ol>

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The authors have nothing to disclose.

수집 된 데이터로부터, 동시 테스트 시나리오는 독립 기포 폴리 우레탄 발포체 시편의 내구성에 영향을 미치지 않았 음을 알 수있다. 이 실패로 건식 및 습식 표본 (그림 6) 유의 한 차이가 변위 (그림 5) 및 ​​잔류 하중을 비교하여 볼 수 있습니다. (7) 잔류 강도 시험 후 시편의 사진을 보여줍니다. 건조 표본의 변위가 24 시간의 관찰 간격 내에 ?...

고분자 및 섬유 강화 고분자 (FRP) 복합 재료는 항공기 및 우주선, ​​해군 함정, 사회 기반 시설에 이르기까지, 엔지니어링 구조의 다양한 채택되었다 (Katnam 등. 1, Hollaway 2, Mouritz 등의 등의 예 리뷰에 대한 참조 . 3), 봉합 및 임플란트 보철 및 생체 재료에 자동차와 기차, 풍력 터빈 블레이드. 이들 물질 &#39;내구성의 조합을 포함 할 수있다 복잡한 서비스 시나리오) 열 - 기계적 하중 예는 동결 - 해동주기를 사회 기반 시설 4, / 초음속 비행 5 프로필, 금속 백업 폴리에틸렌의 마모에 의해 영향을 받는다 6) ; 때문에 환경 및 화학 물질, 예를 들면, 해수, 제빙, 항공 및 해상 구조물 7-10, 타액 (11)에 폴리 메틸 메타 크릴 레이트 치과 복합 재료의 열화 유압 유체 나) 저하; C) 복잡한 INTE고정 또는 결합 관절, 서로 다른 물질 사이 예를 들어, 갈바닉 부식 및 디 본딩에서 재료의 ractions 항공기 알루미늄 피부, 또는 스테인리스 강 (12)에 의해 고정 탄소 / PEEK 뼈 접시에 탄소 / 섬유 패치 수리 여부. 불행히도 이들 재료의 장기 내구성에 동시 - 서비스 자극의 영향에 대한 지식이 제한되어있다. 대부분의 중합체는 점탄성 물질로 분류 할 수있다. 기계적 하중 및 환경 조건이 크게 중합체의 점탄성 응답에 영향을 미친다. 따라서, 이러한 물질 &#39;장기 동작에 대한 신뢰할 수있는 모델을 결합 hygrothermal, 기계적, 화학적 자극에 시간에 따른 응답을 통합 할 수 있어야한다. 차례로 이것은 디자인 예측, 안전 및 상태 기반 유지 보수 / 교체 프로토콜을 향상시킬 수 있습니다. hygrothermal 효과에 대한 실험 테스트에 큰 문학 본체가예를 hygrothermal 확산 시험 : 시료의 스케일이 허용하는 경우, 물질 시료를 원하는 온도 및 습도 수준에서 챔버에 위치 될 수있다. 샘플로부터 주 10,13-17 년에, 주어진 시간에 대한 자신의 질량 및 / 또는 부피의 변화를 측정하기 위해 주기적으로 제거된다. hygrothermal 시험은 재료의 기계적 반응에 hygrothermal 자극의 효과에 대한 정보를 제공 기계적 시험, 즉, 잔여 정적 / 피로 강도 / 파괴 역학 테스트 17-19, 다음에 할 수있다. 테스트 데이터 농도, 응력, 온도, 에이징 가역적 물리적 / 가소 불가역 화학 반응에 대한 종속성을 포함 단순한 모델 Fickian 확산에서, 가변 복잡도의 확산 모델에 장착 될 수있다. 이 실험 출력은 추가 구조 분석에 통합 될 수 있습니다. 몇몇 저자는 동시 숨바꼭질의 영향을 다루었 다grothermal 및 기계적 자극. 그 연구 FRP 복합 재료 중 노이만과 Garom 침지 (20) 스트레스와 증류수에 강세 표본. 압축 응력이 스테인리스 내부 스프링 시험편을 배치하여 도포하고, 다른 스프링 강성과 압축 하중을 이용하여 부하를 조정. 유사한 절차가 완 외. (21)에 의해보고된다. Helbling 및 다른 Karbhari 22 퍼센트 상대 습도 (RH %)의 온도 레벨에 대한 환경 챔버 내부 굽힘 치구를 이용. 프리 컨디셔닝 된 시험편은 그 합성 용 정적 인장 변형의 비율에 대응하는, 소정의 굽힘 응력 레벨을 실시 하였다. 프리 차드 및 Kasturiarachchi 23은 대형 유리 데시 케이 선반에 배치 된 스테인리스 강 4 점 굽힘 지그 (시편 당 하나)를 준비했다. 데시 케이 터가 부분적으로 증류수로 채워졌다, BU을 방지하기 위해 작은 누수를했다압력 ildup 및 95 % RH에서 습도 챔버에 넣었다. 갤러과 털리 7 결합 크리프로드 및 100 % RH에서 자신의 내구성을 위해 해양 급 FRP 복합 표본을 조사 하였다. 충분히 해수에 침지하면서 샘플은 실패 정적 굴곡 하중의 20 %에 해당하는 일정 하중에서 4 점 굽힘에 로딩 하였다. 크리프 편향 중앙 단면 빔, 및 유리판의 외면 사이의 두께 게이지를 사용하여 주기적으로 획득되었다 (그러한 측정 챔버 외부에 수행되었음을 추론한다). 압델 Magid 등. (24)는 표본이 궁극적 축 방향 하중의 20 %, 섬유 방향을 따라 장력에로드 된 바와 같이, NASA 랭글리에 의해 제공되었다 인바 환경기구에 유리 / 에폭시의 샘플을 배치했다. Ellyin 및 Rohrbarcher 25 일까지 140 일 동안 hygrothermal 테스트를 실행 한 후 유압 시험기 피로 시험편을 시험했다. 시편S는 튜브와 물 공급 장치에 연결 치즈 젖은 천으로 감쌌다. 얼 등. (26)는 자신의로드기구와 대형 환경 챔버 (5.5 m 3)의 표본을 위치. 많은 실험 연구에서 논의 된 바와 같이, 환경 조건은 중합체 &#39;기계적 특성과 응답에 영향을 미친다. 일부 제한된 실험은 또한 기계적 응력 / 변형의 존재는 중합체의 확산 공정에 영향을 미치는 것으로 나타났다. 따라서, 기계적 및 비 기계적 영향하에 모두 고분자 계 재료의 전체적인 성능에 대한 이해를 강화하기 위해 동시 테스트에 대한 필요성이 존재한다. 이 문서에 설명 된 테스트 플랫폼의 디자인 뒤에 여러 가지 목적이 있었다. 우선, 플랫폼은 풍력 터빈 용 FRP 샌드위치 복합체의 다른 유형의 hygrothermo 기계적 거동 다년 조사에 실험 장치의 일부차 해군 엔지니어링 응용 프로그램. 테스트 데이터는 합성 중합체 용 점탄성 구성 방정식의 파라미터를 보정하는 데 사용된다. 구성적인 모델은 Muliana와 공동으로 27 ~ 30 년에 걸쳐 개발 작업에 근거합니다. 제 2 대물 쉽게 질량 측정을 위해 스케일 예 연구소 (재배치 또는 유체의 소스로 될 수 일례위한 저비용이고 사용자 친화적 인 테스트 플랫폼, 예를 들어, 한 사람은이 것이었다 수도꼭지, fumehood 또는 가연성 캐비닛). 세 번째 목적은, 따라서, 표본은 화학 약품에 침지 될 수있는 공통 서비스에 사용되는 화학 물질의 수 (우주 항공 분야 8-10 청소용 특히 유압 유체, 제빙)에 내성 테스트 플랫폼을 생성하기 위해, 그리고 내구성을 평가 할 수있다. 챔버 (도 1) 고밀도로 제조 하였다 polyethyleNE, 이는 높은 화학적 저항성을 갖는다. 전술 한 바와 같이, 이는 향후 연구가 유압 유체에 침지 복합 hygrothermo 기계적 조사, 제빙, 세정 용제를 포함 할 것으로 예상된다. 열 조절은 시험의 일체 형태이기 때문에, 발포 폴리스티렌 발포체는 탱크의 측면 주위에 적합하고, 환경과의 열 교환을 방지하기 위해, 테이프 및 철골 자체에 의해 제 위치에 고정. 챔버 (도 2)의 뚜껑은 사용자가 방해없이 시험 동안에 시험 시료를 관찰 할 수 있도록 투명, 9.525 mm 두께의 폴리 카보네이트를 제조 하였다. 탱크 뚜껑의 양쪽에 브래킷 오버행 아래로 슬라이드를 가공했다 알루미늄 T 바 의해 제자리에 고정된다. 시편의 굽힘은 뚜껑에서 내려 걸어, 뚜껑의 슬롯을 통해 고정되어 세 알루미늄 블록에 의해 제정된다. 세 블록 네의 최대 수뚜껑 슬롯 블록 간격이 시험편의 길이에 따라 조절 될 수 있도록하면서 pecimens가 한번에 테스트된다. 각 블록은 ASTM 표준 D790-10 준수에, 12.7 mm 직경 접촉면에서 반올림됩니다. 시편은 굽힘 유도하기 위해 그 중심에 적용 상향 력 (1-2도)로, 세 개의 블록이 아래에 위치한다. 장치는 최대 다양성과 사용 편의성을 염두에두고 설계되었습니다. 41.275 mm 직경 캐스터는 이동성을 위해 챔버 아래에 체결된다. 그들 위에, 탱크 지원을위한 와이어 메쉬 바닥과 크로스 빔에 용접 된 강철 프레임에 의해 지원된다. 외부 탱크 코너에 대한 각도 stock 스페이서 (나중에 논의, 문자열 냄비 장치) 오버 헤드 무게와 변위 게이지에 의해 분쇄되는 절연을 유지하기 위해 제작되었다. 상단의 주위에, 각 주가는 프레임 다시 사용되었다. 풀리 및 문자열 가변 저항 시스템은 measu하기미드 스팬 편향 재 네 개의 강, 평방 튜브 아치 (그림 3)에 장착되어 있습니다. 이 네 가지 중 중심이 아치는 문자열 전위차계를 수행하고 표본의 다양성을 설명하기 위해 조정할 수 있습니다. 세 갈래 전자 출력을하고 전위차계 (개폐식 키 방아 끈에서 발견 될 수있는) 문자열 포텐셔미터는 비틀림 스프링을 사용하여 구성 하였다. 풀리 정렬 및 조정 무게 응용 프로그램에 대한 챔버의 측면을 통해 매달려로드의 표본으로 단단한 연결에서 실행하는 강철 케이블에 사용 장착되어있다. 부하는 케이블, 풀리, 연결기 및 일련의 볼트를 사용하여 시험편에인가된다. 10mm 크로스 바 스팬의 중간 접촉되도록 첫째, 시편은 U 볼트에 배치됩니다. 각 단부에서 아이 볼트와 9.525 mm 직경의 강철 막대이어서 U 볼트에 연결된다. 이 스틸 연결 챔버의 뚜껑을 통과한다. 강철 케이블 및 케블라 thread는 U 볼트 반대 아이 볼트에 부착된다. 이 문자열 전위차계에서 케블라 (Kevlar) 스레드가 단단한 지점에서 데이터를 읽을 수 있습니다. 강철 케이블 위쪽으로 계속 부하 탱크의 주위에 도포 될 수 있도록 두 개의 풀리 통과. 이어서 케이블 슬롯 중량 걸이 역할 9.525 mm 직경 강철 막대에 부착된다. 이 행거 슬롯 가중치 원하는 하중을 적용하기 위해 설정 될 수있는 장소를 제공한다.

<table border="0" cellpadding="0" cellspacing="0" width="581">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:127px;">Name of Material/</td>
			<td rowspan="2" style="width:140px;">Company</td>
			<td rowspan="2" style="width:129px;">Catalog Number</td>
			<td rowspan="2" style="width:185px;">Comments/Description</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:127px;">Equipment</td>
		</tr>
		<tr height="64">
			<td height="64" style="height:64px;width:127px;">Aluminum 6061 rectangular bars</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">8975K268, 1668T72, 7062T17,&#160;</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Aluminum 6061 90 deg. angles</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">8982K91, 8982K14&#160;</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">440C stainless steel</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">6253K52</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="21">
			<td height="43" rowspan="2" style="height:43px;width:127px;">High-density polyethylene sheets</td>
			<td rowspan="2" style="width:140px;">Tap Plastics, USA</td>
			<td rowspan="2" style="width:129px;">N/A (0.236 in. thick x 10.75 in. wide x 16.75 in. long)</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="21">
			<td height="43" rowspan="2" style="height:43px;width:127px;">High-density polyethylene sheets</td>
			<td rowspan="2" style="width:140px;">Tap Plastics, USA</td>
			<td rowspan="2" style="width:129px;">N/A (0.354 in. thick x 6 in. wide x 10 in. long)</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="21">
			<td height="43" rowspan="2" style="height:43px;width:127px;">High-density polyethylene sheets</td>
			<td rowspan="2" style="width:140px;">Tap Plastics, USA</td>
			<td rowspan="2" style="width:129px;">N/A (0.354 in. thick x 6 in. wide x 16.75 in. long)</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="21">
			<td height="43" rowspan="2" style="height:43px;width:127px;">Polycarbonate sheets</td>
			<td rowspan="2" style="width:140px;">Tap Plastics, USA</td>
			<td rowspan="2" style="width:129px;">N/A (0.375 in thick, 11.5 in. wide, 17.5 in long)</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="21">
			<td height="43" rowspan="2" style="height:43px;width:127px;">Expanded polystyrene foam</td>
			<td rowspan="2" style="width:140px;">Home Depot</td>
			<td rowspan="2" style="width:129px;">Model # 310880 Internet # 202532855</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Galvanized steel rope</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">3498T63</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Steel eye bolt</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">3013T341</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="21">
			<td height="43" rowspan="2" style="height:43px;width:127px;">Low-carbon steel 90 deg. angle</td>
			<td rowspan="2" style="width:140px;">McMaster-Carr, USA</td>
			<td rowspan="2" style="width:129px;">9017K444&#160;</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="78">
			<td height="100" rowspan="2" style="height:101px;width:127px;">Low-carbon steel rods</td>
			<td rowspan="2" style="width:140px;">McMaster-Carr, USA</td>
			<td rowspan="2" style="width:129px;">8920K84, 8920K75, 8920K231, 8920K135, 8920K84&#160;&#160;&#160;</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="58">
			<td height="80" rowspan="2" style="height:81px;width:127px;">Low-carbon steel tubes</td>
			<td rowspan="2" style="width:140px;">McMaster-Carr, USA</td>
			<td rowspan="2" style="width:129px;">6527K314, 8910K394, 8910K395, 8920K94&#160;&#160;</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">304 stainless steel U-bolt</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">8896T104</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Steel pulley</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">3099T34</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">1008 carbon steel sheets</td>
			<td style="width:140px;">McMaster-Carr, USA</td>
			<td style="width:129px;">9302T113</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Light duty swivel casters</td>
			<td style="width:140px;">Harbor Freight, USA</td>
			<td style="width:129px;">41519</td>
			<td style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="21">
			<td height="43" rowspan="2" style="height:43px;width:127px;">100-lbf Vinyl Weight Set</td>
			<td rowspan="2" style="width:140px;">Overstock.com</td>
			<td rowspan="2" style="width:129px;">11767059</td>
			<td rowspan="2" style="width:185px;">Part of testing platform</td>
		</tr>
		<tr height="22">
		</tr>
		<tr height="64">
			<td height="64" style="height:64px;width:127px;">Closed-cell polyurethane foam</td>
			<td style="width:140px;">General Plastics, USA</td>
			<td style="width:129px;">FR-3704</td>
			<td style="width:185px;">Testing samples</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Deionized water</td>
			<td style="width:140px;">Faucet, PurLab filtering system</td>
			<td style="width:129px;">N/A</td>
			<td style="width:185px;">Conditioning fluid of tank</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Torsional spring</td>
			<td style="width:140px;">Retractable Key Clip, Ebay, USA</td>
			<td style="width:129px;">Lot 10</td>
			<td style="width:185px;">Used to build string potentiometer</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">Kevlar thread</td>
			<td style="width:140px;">Cabela&#8217;s</td>
			<td style="width:129px;">IK-321909</td>
			<td style="width:185px;">Used to build string potentiometer</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:127px;">10 kOhm potentiometer</td>
			<td style="width:140px;">Ebay, USA</td>
			<td style="width:129px;">3590S-2-103L</td>
			<td style="width:185px;">Used to build string potentiometer</td>
		</tr>
		<tr height="64">
			<td height="64" style="height:64px;width:127px;">Digital multimeter</td>
			<td style="width:140px;">Harbor Freight, USA</td>
			<td style="width:129px;">98674</td>
			<td style="width:185px;">Used to take resistance measurements of string potentiometer</td>
		</tr>
	</tbody>
</table>

a testing platform for durability studies of polymers and fiber-reinforced polymer composites under concurrent hygrothermo-mechanical stimuli

서비스 조건 하에서 중합체 및 섬유 강화 고분자 복합 재료의 내구성은 강력한 설계 및 조건 기반 유지 보수를 위해 해결되어야 할 중요한 측면이다. 이들 재료는 항공기 및 선박 구조에서, 교량, 바람 터빈 블레이드, 생체 재료 및 생의학 임플란트 엔지니어링 다양한 애플리케이션에서 채용된다. 고분자는 점탄성 물질이다, 그들의 반응은 매우 비선형 따라서 예측하고 자신의에서 서비스 성능을 모니터링하기가 도전 할 수 있습니다. 여기에 제공된 실험실 규모의 테스트 플랫폼은 동시 기계적 하중 및 이들 물질에 대한 환경 조건의 영향의 조사를 지원합니다. 이 플랫폼은 낮은 비용과 사용자 친화적으로 설계되었습니다. 그 내성 물질로 인해 유체에의 서비스 노출 화학적 분해의 연구에 플랫폼이 적응합니다. 실험의 예는 독립 기포 폴리 우레탄에 RT에서 실시 하였다발포체 샘플은 궁극적 정적 하중과 건식 ~ 50 %에 해당하는 중량 로케이션. 결과는 시험 장치는 이러한 연구에 적합한 것으로 나타났다. 결과는 또한 높은 중간 점 변위 및 저급 잔여 실패 하중에 기초하여, 동시 하중 하에서 중합체의 취약성을 더 강조. 권장 사항은 시험 장치에 추가 개선을 위해 만들어집니다.

시험 장치가 성공적으로 3 점 굽힘 하에서 유체 내에 침지 시험편을 개최하고있다. 합리적인 정밀도로, 표본로드 할 수 있으며, 중간 지점 편향 변경 전위차계에서 정확한 판독 테스트. 전기 저항의 변화는 0.1 μm의 정도의 변위 분해능 결과, 유효 숫자 4로 기록 될 수있다. Hygrothermo 기계적 테스트는 공칭 치수 215mm 길이 X 24mm X 18mm의 폭, 두께, 폐쇄 - 셀 폴리 우레탄 폼의 시험편...

Watch this Scientific Journal Video about A Testing Platform for Durability Studies of Polymers and Fiber-reinforced Polymer Composites under Concurrent Hygrothermo-mechanical Stimuli at JoVE.com

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 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.

폴리머의 내구성 연구 및 동시 Hygrothermo 기계적 자극에 따라 섬유 강화 고분자 복합 재료에 대한 테스트 플랫폼

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

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13.7K 조회수.  University of California, Davis. 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.

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

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water

For aqueous based supramolecular polymers, the simultaneous control over shape, size and stability is very difficult1. At the same time, the ability to do so is highly important in view of a number of applications in functional soft matter including electronics, biomedical engineering, and sensors. In the past, successful strategies to control the size and shape of supramolecular polymers typically focused on the use of templates2,3, end cappers4 or selective solvent techniques5. 
Here we disclose a strategy based on self-assembling discotic amphiphiles that leads to the control over stack length and shape of ordered, chiral columnar aggregates. By balancing electrostatic repulsive interactions on the hydrophilic rim and attractive non-covalent forces within the hydrophobic core of the polymerizing building block, we manage to create small and discrete spherical objects6,7. Increasing the salt concentration to screen the charges induces a sphere-to-rod transition. Intriguingly, this transition is expressed in an increase of cooperativity in the temperature-dependent self-assembly mechanism, and more stable aggregates are obtained. 
For our study we select a benzene-1,3,5-tricarboxamide (BTA) core connected to a hydrophilic metal chelate via a hydrophobic, fluorinated L-phenylalanine based spacer (Scheme 1). The metal chelate selected is a Gd(III)-DTPA complex that contains two overall remaining charges per complex and necessarily two counter ions. The one-dimensional growth of the aggregate is directed by &pi;-&pi; stacking and intermolecular hydrogen bonding. However, the electrostatic, repulsive forces that arise from the charges on the Gd(III)-DTPA complex start limiting the one-dimensional growth of the BTA-based discotic once a certain size is reached. At millimolar concentrations the formed aggregate has a spherical shape and a diameter of around 5 nm as inferred from 1H-NMR spectroscopy, small angle X-ray scattering, and cryogenic transmission electron microscopy (cryo-TEM). The strength of the electrostatic repulsive interactions between molecules can be reduced by increasing the salt concentration of the buffered solutions. This screening of the charges induces a transition from spherical aggregates into elongated rods with a length &gt; 25 nm. Cryo-TEM allows to visualise the changes in shape and size. In addition, CD spectroscopy permits to derive the mechanistic details of the self-assembly processes before and after the addition of salt. Importantly, the cooperativity -a key feature that dictates the physical properties of the produced supramolecular polymers- increases dramatically upon screening the electrostatic interactions. This increase in cooperativity results in a significant increase in the molecular weight of the formed supramolecular polymers in water.

The goal of this experiment is to determine and control the size, shape and stability of self-assembled discotic amphiphiles in water. For aqueous based supramolecular polymers such level of control is very difficult. We apply a strategy using both repulsive and attractive interactions. The experimental techniques applied to characterize this system are broadly applicable.

물에 Supramolecular 폴리머의 크기, 모양과 안정성을 제어

For aqueous based supramolecular polymers, the simultaneous control over shape, size and stability is very difficult1. At the same time, the ability to do ...

연구

공학

Concurrent Quantitative Conductivity and Mechanical Properties Measurements of Organic Photovoltaic Materials using AFM

Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. Thus, understanding of spatial variations in composition as well as electrical properties of OPV materials is of paramount importance for moving PV technology forward.1,2 In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution. Currently, materials properties measurements performed using commercially available AFM-based techniques (PeakForce, conductive AFM) generally provide only qualitative information. The values for resistance as well as Young's modulus measured using our method on the prototypical ITO/PEDOT:PSS/P3HT:PC61BM system correspond well with literature data. The P3HT:PC61BM blend separates onto PC61BM-rich and P3HT-rich domains. Mechanical properties of PC61BM-rich and P3HT-rich domains are different, which allows for domain attribution on the surface of the film. Importantly, combining mechanical and electrical data allows for correlation of the domain structure on the surface of the film with electrical properties variation measured through the thickness of the film.

Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution.

동시 수량 전도성과 AFM을 사용하여 유기 태양 광 재료의 기계적 성질 측정

Organic photovoltaic  (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale  inhomogeneity of OPV materials affects performance ...

Scalable Nanohelices for Predictive Studies and Enhanced 3D Visualization

Spring-like materials are ubiquitous in nature and of interest in nanotechnology for energy harvesting, hydrogen storage, and biological sensing applications.&#160; For predictive simulations, it has become increasingly important to be able to model the structure of nanohelices accurately.&#160; To study the effect of local structure on the properties of these complex geometries one must develop realistic models.&#160; To date, software packages are rather limited in creating atomistic helical models.&#160; This work focuses on producing atomistic models of silica glass (SiO2) nanoribbons and nanosprings for molecular dynamics (MD) simulations. Using an MD model of &#8220;bulk&#8221; silica glass, two computational procedures to precisely create the shape of nanoribbons and nanosprings are presented.&#160; The first method employs the AWK programming language and open-source software to effectively carve various shapes of silica nanoribbons from the initial bulk model, using desired dimensions and parametric equations to define a helix.&#160; With this method, accurate atomistic silica nanoribbons can be generated for a range of pitch values and dimensions.&#160; The second method involves a more robust code which allows flexibility in modeling nanohelical structures.&#160; This approach utilizes a C++ code particularly written to implement pre-screening methods as well as the mathematical equations for a helix, resulting in greater precision and efficiency when creating nanospring models.&#160; Using these codes, well-defined and scalable nanoribbons and nanosprings suited for atomistic simulations can be effectively created.&#160; An added value in both open-source codes is that they can be adapted to reproduce different helical structures, independent of material.&#160; In addition, a MATLAB graphical user interface (GUI) is used to enhance learning through visualization and interaction for a general user with the atomistic helical structures.&#160; One application of these methods is the recent study of nanohelices via MD simulations for mechanical energy harvesting purposes.

Accurate modeling of nanohelical structures is important for predictive simulation studies leading to novel nanotechnology applications.&#160; Currently, software packages and codes are limited in creating atomistic helical models.&#160; We present two procedures designed to create atomistic nanohelical models for simulations, and a graphical interface to enhance research through visualization.

예측 연구 확장 Nanohelices 향상된 3D 시각화

Spring-like materials are ubiquitous in nature and of interest in nanotechnology for energy harvesting, hydrogen storage, and biological sensing ...

Ultrasonic Welding of Thermoplastic Composite Coupons for Mechanical Characterization of Welded Joints through Single Lap Shear Testing

This paper presents a novel straightforward method for ultrasonic welding of thermoplastic-composite coupons in optimum processing conditions. The ultrasonic welding process described in this paper is based on three main pillars. Firstly, flat energy directors are used for preferential heat generation at the joining interface during the welding process. A flat energy director is a neat thermoplastic resin film that is placed between the parts to be joined prior to the welding process and heats up preferentially owing to its lower compressive stiffness relative to the composite substrates. Consequently, flat energy directors provide a simple solution that does not require molding of resin protrusions on the surfaces of the composite substrates, as opposed to ultrasonic welding of unreinforced plastics. Secondly, the process data provided by the ultrasonic welder is used to rapidly define the optimum welding parameters for any thermoplastic composite material combination. Thirdly, displacement control is used in the welding process to ensure consistent quality of the welded joints. According to this method, thermoplastic-composite flat coupons are individually welded in a single lap configuration. Mechanical testing of the welded coupons allows determining the apparent lap shear strength of the joints, which is one of the properties most commonly used to quantify the strength of thermoplastic composite welded joints.

A straightforward procedure for ultrasonic welding of thermoplastic composite coupons for basic mechanical testing is described. Key characteristics of this ultrasonic welding process are the use of flat energy directors for simplified process preparation and the use of process data for the fast definition of optimum processing conditions.

단일 랩 전단 시험을 통해 용접 조인트의 기계적 특성에 대한 열가소성 복합 쿠폰의 초음파 용접

This paper presents a novel straightforward method for ultrasonic welding of thermoplastic-composite coupons in optimum processing conditions. The ...

Advanced Compositional Analysis of Nanoparticle-polymer Composites Using Direct Fluorescence Imaging

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise composition of these materials is essential, especially in the design of surface catalysts, where the surface concentration of the active component determines the activity of the material. Antimicrobial materials which utilize nanoparticles are a particular focus of this technology. Recently swell encapsulation has emerged as a technique for inserting antimicrobial nanoparticles into a host polymer matrix. Swell encapsulation provides the advantage of localizing the incorporation to the external surfaces of materials, which act as the active sites of these materials. However, quantification of this nanoparticle uptake is challenging. Previous studies explore the link between antimicrobial activity and surface concentration of the active component, but this is not directly visualized. Here we show a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of CdSe/ZnS nanoparticles can be accurately visualized through cross-sectional fluorescence imaging. Using this method, we can quantify the uptake of nanoparticles via swell encapsulation and measure the surface concentration of encapsulated particles, which is key in optimizing the activity of functional materials.

Here we present a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of cadmium selenide quantum dots can be accurately visualized through cross-sectional fluorescence imaging.

직접 형광 이미징을 사용하여 나노 입자 - 고분자 복합 재료의 고급 성분 분석

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise ...

Nanostructured Ag-zeolite Composites as Luminescence-based Humidity Sensors

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high external quantum efficiencies (EQE) and spans the whole visible spectrum. It has been recently reported that the UV excited luminescence of partially Li-exchanged sodium Linde type A zeolites [LTA(Na)] containing luminescent silver clusters can be controlled by adjusting the water content of the zeolite. These samples showed a dynamic change in their emission color from blue to green and yellow upon an increase of the hydration level of the zeolite, showing the great potential that these materials can have as luminescence-based humidity sensors at the macro and micro scale. Here, we describe the detailed procedure to fabricate a humidity sensor prototype using silver-exchanged zeolite composites. The sensor is produced by suspending the luminescent Ag-zeolites in an aqueous solution of polyethylenimine (PEI) to subsequently deposit a film of the material onto a quartz plate. The coated plate is subjected to several hydration/dehydration cycles to show the functionality of the sensing film.

A protocol for the synthesis of moisture-responsive luminescent Ag-zeolite composites is described in this report.

발광 기반 습도 센서와 같은 나노 구조 AG-제올라이트 복합

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high ...

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

The hot stamping and cold die quenching process is increasingly used to form complex shaped structural components of sheet metals. Conventional experimental approaches, such as out-of-plane and in-plane tests, are not applicable to the determination of forming limits when heating and rapid cooling processes are introduced prior to forming for tests conducted under hot stamping conditions. A novel in-plane biaxial testing system was designed and used for the determination of forming limits of sheet metals at various strain paths, temperatures, and strain rates after heating and cooling processes in a resistance heating uniaxial testing machine. The core part of the biaxial testing system is a biaxial apparatus, which transfers a uniaxial force provided by the uniaxial testing machine to a biaxial force. One type of cruciform specimen was designed and verified for the formability test of aluminum alloy 6082 using the proposed biaxial testing system. The digital image correlation (DIC) system with a high-speed camera was used for taking strain measurements of a specimen during a deformation. The aim of proposing this biaxial testing system is to enable the forming limits of an alloy to be determined at various temperatures and strain rates under hot stamping conditions.

This protocol proposes a novel biaxial testing system used on a resistance heating uniaxial tensile test machine in order to determine the forming limit diagram (FLD) of sheet metals under hot stamping conditions.

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

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.

레이저 조사 형 광열 열 분석을 이용한 구조 가열에 의한 지층 결함 국산화

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

Preparation of Aligned Steel Fiber Reinforced Cementitious Composite and Its Flexural Behavior

The aim of this work is to present an approach, inspired by the way in which a compass needle maintains a consistent orientation under the action of the Earth&#39;s magnetic field, for manufacturing a cementitious composite reinforced with aligned steel fibers. Aligned steel fiber reinforced cementitious composites (ASFRC) were prepared by applying a uniform electromagnetic field to fresh mortar containing short steel fibers, whereby the short steel fibers were driven to rotate in alignment with the magnetic field. The degree of alignment of steel fibers in hardened ASFRC was assessed both by counting steel fibers in fractured cross-sections and by X-ray computed tomography analysis. The results from the two methods show that the steel fibers in ASFRC were highly aligned while the steel fibers in non-magnetically treated composites were randomly distributed. The aligned steel fibers had a much higher reinforcing efficiency, and the composites, therefore, exhibited significantly enhanced flexural strength and toughness. The ASFRC is thus superior to SFRC in that it can withstand greater tensile stress and more effectively resist cracking.

This protocol describes an approach for manufacturing aligned steel fiber reinforced cementitious composite by applying a uniform electromagnetic field. Aligned steel fiber reinforced cementitious composite exhibits superior mechanical properties to ordinary fiber reinforced concrete.

The aim of this work is to present an approach, inspired by the way in which a compass needle maintains a consistent orientation under the action of the ...

Installation Method to Enhance Quality Control for Fiber Reinforced Polymer Spike Anchors

Fiber reinforced polymer (FRP) anchors are a promising way to enhance the performance of externally-bonded FRPs applied to existing structures, as they can delay or even prevent debonding failure. However, a major concern faced by designers is the premature failure of the anchors due to stress concentration. Poor installation quality and preparation of the clearance holes can result in stress concentration that provokes this premature failure. This paper deals with an installation method that aims to reduce the impact of the stress concentration and to provide a proper quality control of the preparation of the drill hole. The method involves three parts: the drilling and cleaning of the holes, the smoothing of the hole edges with a customized drill bit, and the installation of the anchor itself, including the impregnation of the anchor dowel and its insertion. Anchor fans (the free length of the spikes) are then bonded to the external FRP reinforcement. For the end anchorage, and in the case of reinforcements with multiple plies, it is recommended that the anchor fan be inserted between two plies to assist the stress-transfer mechanism. 
The proposed procedure is complemented with a design approach for spike anchors, based on an extensive database. It is proposed that the design follow a number of steps, namely: selection of the anchor diameter and subsequent tensile strength of the connector (that is to say, the anchor before fanning out the free end), evaluation of the reduction in the tensile strength due to bending, provision of enough embedment to prevent slippage failure, and consideration of the number and spacing of anchors for a given reinforcement. In this sense, it should be noted that further research is needed in order to obtain a general expression for the contribution of spike anchors to overall bond strength of FRP reinforcements.

This manuscript presents a method for controlling the quality of installation for spike anchors designed to delay delamination of externally bonded fiber reinforced polymers. The protocol includes the preparation of the drill hole and the insertion process. The most influential parameters on the efficiency of the anchors are discussed.

섬유에 대 한 품질 관리를 향상 시키기 위해 설치 방법 강화 폴리머 스파이크 앵커

Fiber reinforced polymer (FRP) anchors are a promising way to enhance the performance of externally-bonded FRPs applied to existing structures, as they ...