Papers by Keyword: Maximum Strain

Abstract: Portable bridges are very important for maintaining mobility in the aftermath of natural disaster or in the battlefield. This requirement has lead to the needs for light-weight bridging system for ease in launching, retracting, transporting, and storing. In this research, a foldable bridge with three sections of beam connected together using the hinges connection has been designed and analyzed. The bridge is constructed using sandwich Carbon Fiber Reinforced Polymer (CFRP) which consists of CFRP and Aluminum Honeycomb, as the skin and core, respectively. The uses of materials are expected will reduce the total weight of bridge without decreasing of overall performance. Failure theories of composite material such as Maximum Stress, Maximum Strain, Tsai-Wu and Tsai-Hill failure theories were selected to generate an allowable strength graph. From the graph, can be seen that, the material stresses are in the allowable stress-strain ranges, therefore, the bridge is capable of carrying the design load with sufficient safety factor.

Abstract: Fatigue lifetime prediction methodology of the vulcanized natural rubber was proposed by incorporating the finite element analysis and fatigue damage parameter determined from fatigue test. Finite element analysis of 3D dumbbell specimen of natural rubber was performed based on a hyper-elastic material model determined from the tension, compression and shear tests. Stroke controlled fatigue tests were conducted using fatigue specimens at different levels of mean strain. The Green-Lagrange strain at the critical location determined from the FEM was used for evaluating the fatigue damaged parameter of the natural rubber. It was shown that the maximum Green-Lagrange strain was proper damage parameter, taking the mean strain effects into account. Fatigue lives of the natural rubber are predicted by using the fatigue damage parameters at the critical location. Predicted fatigue lives of the natural rubber agreed fairly well the experimental fatigue lives a factor of two.