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2. PHD Thesis / Tesis PHD
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Title:	Progressive Failure Characteristics Of Woven Natural Silk Epoxy Composite Tube In Quasi-Static Compression
Authors:	Rahim Ataollah Eshkoor (P47073)
Supervisor:	Che Husna Azhari, Prof
Keywords:	Woven Natural Silk Progressive Failure Characteristics Composite Tube In Quasi-Static Compression Composite materials
Issue Date:	9-Sep-2013
Description:	This study focussed on the crashworthiness characteristics of woven natural silk epoxy composite square tubes energy-absorbers when subjected to quasi-static axial compression. The square tube which simulate the body of the passenger car were in the form of square cross-sections with the dimension of 80 mm x 80 mm and a radius curvature of 5 mm. External trigger mechanism in order to induce progressive failure to the specimens has been selected to be employed in axial quasi-static compression test of woven natural silk epoxy composite tubes. In this study variables were the length of the tubes 50 mm, 80 mm and 120 mm respectively and the thicknesses of the walls, consisting of laminates of silk epoxy with 12, 24 and 30 plies, corresponding to equivalent wall thicknesses of 1.7 mm, 3.4 mm and 4.2 mm respectively. The parameters measured were the total absorbed energy (Etotal), and the crush force efficiency (CFE). The Etotal is the measure of the amount of energy that the structure can absorb during a collision and thus is a measure of its strength, while CFE gives a quantitative indication of the mode of failure of the composites. The mode of failure was observed using photography. Under the quasi static axial compression tests all the specimens exhibited progressive failure. In this study the specimens failed in local buckling except the 12 layers tube with 120 mm length size. Results showed that the highest values of Etotal were obtained for the specimens with 30 silk/epoxy laminates and 120 mm length size which is the same as previous study in attribute to number of laminates and length size but the amount of absorbed energy in this study is greater than the attained one in previous study. The maximum value for CFE obtained in specimen with 30 layer silk epoxy laminates and 50 mm length size was equal to 0.52. This value is 1.7 times greater than what was achieved in previous study. The results imply that trigger plays significant role in energy absorption capacity and failure mode of the composite tubes. The failure morphology of tubes showed that the high friction sliding of tube against metal plates and trigger, delamination, tear at the corners and at the intersection of tube and trigger are the main mechanisms which contributed in the process of energy absorption. The test parameters obtained experimentally were simulated using MSC Dytran a non-linear finite element explicit analysis software implemented to the simulation since this mimics the characteristics of the behaviour of the crashworthiness. The results from the finite element analysis were validated against the experimental results and a good agreement was observed. This agreement builds confidence in the future use of non-linear finite element for the design of silk epoxy composite structure subjected to crash loading in energy-absorbing applications such as in the automotive as well as in the aircraft industries.,PhD
Pages:	148
Call Number:	TA418.9.C6 .E764 2013 3
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

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