Volume 12: Processing and Engineering Applications of Novel Materials, 2010
A new class of thermal microactuators, Z-shaped thermal actuator, is introduced in comparison wit... more A new class of thermal microactuators, Z-shaped thermal actuator, is introduced in comparison with the well-established V-shaped thermal actuator. Though they share many features in common, Z-shaped thermal actuator offers several advantages: compatibility with anisotropic etching, smaller feature size, larger displacement, and larger variety of stiffness and output force. While the Z-shaped thermal actuator was modeled analytically and verified by multiphysics finite element analysis (FEA), the beam width and length of the central beam were identified as the major design parameters in tuning the device displacement, stiffness, stability and output force. Experimental measurements were taken on three arrays of Z-shaped thermal actuator with variable parameters. Results agreed well with the finite element analysis. The development of Z-shaped thermal actuator is applicable in simultaneous sensing and actuating applications. During the quasi-static test of individual Z-shaped thermal ...
Monotonic tensile tests are conducted on seven different Glare grades of fiber metal laminates. I... more Monotonic tensile tests are conducted on seven different Glare grades of fiber metal laminates. In-situ stress–strain curves of glass/epoxy laminate interleaved in Glare 2(3/2) are exposed with the application of metal volume fraction method using the stress–strain curves of Glare 2(3/2) and Aluminum 2024-T3 in unidirectional and transverse directions. The strain–stress curves of cross-ply Glares are predicted by the modification of this method with an empirical parameter and a second parameter considering the relative glass/epoxy laminate thickness ratios of Glare grades. Modified metal volume fraction method presented in this study can be used as a preliminary estimation of stress–strain curves of multiple possible fiber metal laminate configurations without testing.
This article was published in the above mentioned Springer issue. The material, including all por... more This article was published in the above mentioned Springer issue. The material, including all portions thereof, is protected by copyright; all rights are held exclusively by Springer Science + Business Media. The material is for personal use only; commercial use is not permitted. Unauthorized reproduction, transfer and/or use may be a violation of criminal as well as civil law. Abstract Impact responses and damage of various fiber-metal laminates were studied using a drop-weight instrument with the post-impact damage characteristics being evaluated through ultrasonic and mechanical sectioning techniques. The first severe failure induced by the low-velocity drop-weight impact occurred as delamination between the aluminum and fiber-epoxy layers at the non-impact side. It was followed by a visible shear crack in the outer aluminum layer on the non-impact face. Through-thickness shear cracks in the aluminum sheets and severe damage in the fiber laminated layers (including delamination between adjacent fiber-epoxy laminae with different fiber orientations) developed under higher energy impacts. The impact properties of fiber-metal laminates varied with different constituent materials and fiber orientations. Since it was punched through easily, the aramid-fiber reinforced fiber-metal laminates (ARALL) offered poorer impact resistance than the glass-fiber reinforced fiber-metal laminates (GLARE). Tougher and more ductile aluminum alloys improved the impact resistance. GLARE made of cross-ply prepregs provided better impact resistance than GLARE with unidirectional plies. Keywords Drop-weight (low-velocity) impact. Fiber-metal laminates (GLARE and ARALL). Ultrasound
Volume 12: Processing and Engineering Applications of Novel Materials, 2010
A new class of thermal microactuators, Z-shaped thermal actuator, is introduced in comparison wit... more A new class of thermal microactuators, Z-shaped thermal actuator, is introduced in comparison with the well-established V-shaped thermal actuator. Though they share many features in common, Z-shaped thermal actuator offers several advantages: compatibility with anisotropic etching, smaller feature size, larger displacement, and larger variety of stiffness and output force. While the Z-shaped thermal actuator was modeled analytically and verified by multiphysics finite element analysis (FEA), the beam width and length of the central beam were identified as the major design parameters in tuning the device displacement, stiffness, stability and output force. Experimental measurements were taken on three arrays of Z-shaped thermal actuator with variable parameters. Results agreed well with the finite element analysis. The development of Z-shaped thermal actuator is applicable in simultaneous sensing and actuating applications. During the quasi-static test of individual Z-shaped thermal ...
Monotonic tensile tests are conducted on seven different Glare grades of fiber metal laminates. I... more Monotonic tensile tests are conducted on seven different Glare grades of fiber metal laminates. In-situ stress–strain curves of glass/epoxy laminate interleaved in Glare 2(3/2) are exposed with the application of metal volume fraction method using the stress–strain curves of Glare 2(3/2) and Aluminum 2024-T3 in unidirectional and transverse directions. The strain–stress curves of cross-ply Glares are predicted by the modification of this method with an empirical parameter and a second parameter considering the relative glass/epoxy laminate thickness ratios of Glare grades. Modified metal volume fraction method presented in this study can be used as a preliminary estimation of stress–strain curves of multiple possible fiber metal laminate configurations without testing.
This article was published in the above mentioned Springer issue. The material, including all por... more This article was published in the above mentioned Springer issue. The material, including all portions thereof, is protected by copyright; all rights are held exclusively by Springer Science + Business Media. The material is for personal use only; commercial use is not permitted. Unauthorized reproduction, transfer and/or use may be a violation of criminal as well as civil law. Abstract Impact responses and damage of various fiber-metal laminates were studied using a drop-weight instrument with the post-impact damage characteristics being evaluated through ultrasonic and mechanical sectioning techniques. The first severe failure induced by the low-velocity drop-weight impact occurred as delamination between the aluminum and fiber-epoxy layers at the non-impact side. It was followed by a visible shear crack in the outer aluminum layer on the non-impact face. Through-thickness shear cracks in the aluminum sheets and severe damage in the fiber laminated layers (including delamination between adjacent fiber-epoxy laminae with different fiber orientations) developed under higher energy impacts. The impact properties of fiber-metal laminates varied with different constituent materials and fiber orientations. Since it was punched through easily, the aramid-fiber reinforced fiber-metal laminates (ARALL) offered poorer impact resistance than the glass-fiber reinforced fiber-metal laminates (GLARE). Tougher and more ductile aluminum alloys improved the impact resistance. GLARE made of cross-ply prepregs provided better impact resistance than GLARE with unidirectional plies. Keywords Drop-weight (low-velocity) impact. Fiber-metal laminates (GLARE and ARALL). Ultrasound
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