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Full-Text Articles in Mechanical Engineering
Experimental And Fem Study Of Thermal Cycling Induced Microcracking In Carbon/Epoxy Triaxial Braided Composites, Chao Zhang, Wieslaw Binienda, Gregory Morscher, Richard Martin, Lee Kohlman
Experimental And Fem Study Of Thermal Cycling Induced Microcracking In Carbon/Epoxy Triaxial Braided Composites, Chao Zhang, Wieslaw Binienda, Gregory Morscher, Richard Martin, Lee Kohlman
Wieslaw K. Binienda
The microcrack distribution and mass change in T700s/PR520 and T700s/3502 carbon/epoxy braided composites exposed to thermal cycling was evaluated experimentally. Acoustic emission was utilized to record the crack initiation and propagation under cyclic thermal loading between −55 °C and 120 °C. Transverse microcrack morphology was investigated using X-ray computed tomography. The differing performance of two kinds of composites was discovered and analyzed. Based on the observations of microcrack formation, a meso-mechanical finite element model was developed to obtain the resultant mechanical properties. The simulation results exhibited a decrease in strength and stiffness with increasing crack density. Strength and stiffness reduction …
Experimental And Fem Study Of Thermal Cycling Induced Microcracking In Carbon/Epoxy Triaxial Braided Composites, Chao Zhang, Wieslaw Binienda, Gregory Morscher, Richard Martin, Lee Kohlman
Experimental And Fem Study Of Thermal Cycling Induced Microcracking In Carbon/Epoxy Triaxial Braided Composites, Chao Zhang, Wieslaw Binienda, Gregory Morscher, Richard Martin, Lee Kohlman
Dr. Gregory N. Morscher
The microcrack distribution and mass change in T700s/PR520 and T700s/3502 carbon/epoxy braided composites exposed to thermal cycling was evaluated experimentally. Acoustic emission was utilized to record the crack initiation and propagation under cyclic thermal loading between −55 °C and 120 °C. Transverse microcrack morphology was investigated using X-ray computed tomography. The differing performance of two kinds of composites was discovered and analyzed. Based on the observations of microcrack formation, a meso-mechanical finite element model was developed to obtain the resultant mechanical properties. The simulation results exhibited a decrease in strength and stiffness with increasing crack density. Strength and stiffness reduction …
Understanding Effectiveness Of Stitching In Suppression Of Impact Damage: An Empirical Delamination Reduction Trend For Stitched Composites, Kwek Tan, N. Watanabe, Y. Iwahori, T. Ishikawa
Understanding Effectiveness Of Stitching In Suppression Of Impact Damage: An Empirical Delamination Reduction Trend For Stitched Composites, Kwek Tan, N. Watanabe, Y. Iwahori, T. Ishikawa
Dr. Kwek-Tze Tan
In this paper, a novel empirical trend has been identified to understand the delamination reduction in stitched composites subjected to impact loading. This empirical-based Delamination Reduction Trend (DRT) is developed based on an extensive series of low-velocity impact tests using specimens of different laminate thicknesses, stitch densities and stitch thread linear (mass) densities, subjected over a range of impact energy levels. The DRT simply relates two parameters: normalized delamination area (DelamNorm) and stitch fiber volume fraction (Vft), to characterize the effectiveness of stitching in impact damage suppression. DRT evidently shows a bi-linear behavior: first, …
Effect Of Stitch Density And Stitch Thread Thickness On Low-Velocity Impact Damage Of Stitched Composites, Kwek Tan, N. Watanabe, Y. Iwahori
Effect Of Stitch Density And Stitch Thread Thickness On Low-Velocity Impact Damage Of Stitched Composites, Kwek Tan, N. Watanabe, Y. Iwahori
Dr. Kwek-Tze Tan
Effect of stitch density and stitch thread thickness on low-velocity impact damage of stitched composites is investigated experimentally. Physical examination on damage surfaces shows that stitches perform as crack initiators, as well as crack arrestors. Longer matrix cracks are observed in densely-stitched composites, in contrast to isolated matrix cracks found in moderately-stitched composites. Ultrasonic C-scan evidently compares the delamination areas and concludes that specimens with higher stitch density and thread thickness are more capable of impeding delamination growth by effectively bridging delamination cracks. Load–time curves reveal that the onset of delamination is not influenced by stitch density and thread thickness. …
Effect Of Stitch Density And Stitch Thread Thickness On Compression After Impact Strength And Response Of Stitched Composites, Kwek Tan, N. Watanabe, Y. Iwahori, T. Ishikawa
Effect Of Stitch Density And Stitch Thread Thickness On Compression After Impact Strength And Response Of Stitched Composites, Kwek Tan, N. Watanabe, Y. Iwahori, T. Ishikawa
Dr. Kwek-Tze Tan
In this paper, the damage failure and behaviour of stitched composites under compression after impact (CAI) loading are experimentally investigated. This study focuses on the effect of stitch density and stitch thread thickness on the CAI strength and response of laminated composites reinforced by through-thickness stitching. Experimental findings show that stitched composites have higher CAI failure load and displacement, which corresponds to higher energy absorption during CAI damage, mainly attributed to greater energy consumption by stitch fibre rupture. The coupling relationships between CAI strength, impact energy, stitch density and stitch thread thickness are also revealed. It is understood that the …