Experimental and numerical studies on an energy piled wall: The effect of thermally activated pile spacing

2012 ◽

Author(s):

Fan Yang ◽

Nan Lei ◽

Xiaolin Chen ◽

Jiaping Yang

Keyword(s):

Operating Temperature ◽

Finite Element Models ◽

Rotational Angle ◽

Confined Polymers ◽

New Device ◽

Thermally Activated ◽

Numerical Studies ◽

Central Platform ◽

Composite Microstructure ◽

Thermally Actuated

In this paper, design modeling of an in-plane rotary microactuator with electro-thermal unimorph is conducted. The electro-thermal unimorph is made of confined polymers consisting of a silicon skeleton filled with SU-8 photoresist. Due to the effect of thermal expansion mismatch between silicon and SU-8, the composite unimorph bends laterally when thermally activated. Numerical studies are carried out to investigate the effects of the silicon/SU-8 composite microstructure on the unimorph deflection. Unimorph dimensions are optimized to generate a large displacement at the cantilever tip. The microactuator device is comprised of four identical unimorphs and a suspended central platform. When thermally actuated, the displaced unimorphs can rotate the central platform bi-directionally in the platform plane. Finite element models of the microactuator device are built to investigate the device performance. A new device layout with a detached central platform structure is proposed to increase the rotational angle while maintaining a reasonable operating temperature. Our results show that the optimized microactuator can achieve a rotational angle of 4 degrees under a small actuating voltage input of 1V.

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Experimental and Numerical Studies on High-Pressure Composite Cylinders Subjected to Localized and Engulfing Fire

Journal of Pressure Vessel Technology ◽

10.1115/1.4024705 ◽

2013 ◽

Vol 135 (5) ◽

Cited By ~ 2

Author(s):

Jinyang Zheng ◽

Kesheng Ou ◽

Zhengli Hua ◽

Yongzhi Zhao ◽

Jun Hu ◽

...

Keyword(s):

High Pressure ◽

Exposure Time ◽

Three Dimensional ◽

Fire Exposure ◽

Composite Cylinder ◽

Activation Time ◽

Compressed Natural Gas ◽

Thermally Activated ◽

Numerical Studies ◽

Composite Cylinders

Vehicle fires may lead to on-board high-pressure composite cylinders experiencing a term of localized and engulfing fire. During this period, the composite cylinder would be degraded and even burst before pressure relief device (PRD) could be activated to release internal high-pressure gas. In this paper, experimental investigation for such cylinders subjected to localized and engulfing fire was conducted on an aluminum liner composite cylinder filled with hydrogen. A three-dimensional computational fluid dynamics (CFD) model is developed to study the key factors influencing PRD activation time. The effects of hydrogen and compressed natural gas (CNG) as filling media, cylinder pressure and localized fire exposure time are analyzed in detail. The experimental results showed that pressure and temperature of internal gas rose very slowly during the localized fire. In addition, Hydrogen and CNG as filling media with different pressures have weak influence on the activation time of thermally activated PRD (TPRD), but have significant effect on the activation time of pressure-activated PRD (PPRD). TPRD can respond more quickly to protect the hydrogen composite cylinder than PPRD. PRD activation time increases as the localized fire exposure time is extended.

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