The Experts below are selected from a list of 52563 Experts worldwide ranked by ideXlab platform
Yiu-wing Mai - One of the best experts on this subject based on the ideXlab platform.
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effect of fibre matrix adhesion on Residual Strength of notched composite laminates
Composites Part A-applied Science and Manufacturing, 1998Co-Authors: Akbar Afaghikhatibi, Glyn Lawcock, Yiu-wing MaiAbstract:Effects of fibre/matrix adhesion and Residual Strength of notched polymer matrix composite laminates (PMCLs) and fibre reinforced metal laminates (FRMLs) were investigated. Two different levels of adhesion between fibre and matrix were achieved by using the same carbon fibres with or without surface treatments. After conducting short-beam shear and transverse tension tests for fibre/matrix interface characterisation, Residual Strength tests were performed for PMCLs and FRMLs containing a circular hole/sharp notch for the two composite systems. It was found that laminates with poor interfacial adhesion between fibre and matrix exhibit higher Residual Strength than those with strong fibre/matrix adhesion. Major failure mechanisms and modes in two composite systems were studied using SEM fractography. The effective crack growth model (ECGM) was also applied to simulate the Residual Strength and damage growth of notched composite laminates with different fibre/matrix adhesion. Predictions from the ECGM were well correlated with experimental data.
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A statistical model of Residual Strength and fatigue life of composite laminates
Composites Science and Technology, 1995Co-Authors: Xiaoxue Diao, Yiu-wing MaiAbstract:A statistical model for the prediction of Residual Strength and fatigue life of composite laminates has been developed on the basis of the statistical nature of fatigue damage and the concept of a representative volume for damage evolution. The representative volume consists of a critical element which defines failure and Residual Strength and a subcritical element that describes stress distributions associated with progressive damage accumulation. The statistical equation of Residual Strength evolution is first established and the density distribution function of the Residual Strength is then derived from the static Strength distribution. The Residual Strength and the fatigue life of composite laminates can be determined from the knowledge of these equations together with a stress redistribution factor which controls the global stiffness reduction. Comparisons of experimental data with theoretical predictions for glass/epoxy unidirectional and cross-plied laminates show good agreement, thus confirming the usefulness of the model.
Tuo Huang - One of the best experts on this subject based on the ideXlab platform.
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nonlinear fatigue damage model of asphalt mixture based on dynamic modulus and Residual Strength decay
Materials, 2019Co-Authors: Hongfu Liu, Xinyu Yang, Chengdong Xia, Jianlong Zheng, Tuo HuangAbstract:In order to describe the fatigue damage state of asphalt mixture more reasonably, direct tensile tests of the fatigue and the Residual Strength under stress levels of 1.00 MPa, 0.50 MPa and 0.25 MPa with five parallel tests were carried out. The trabecular specimens of AC-13C asphalt mixture (25 cm × 5 cm × 5 cm) were manufactured with Styrene-Butadiene-Styrene (SBS) modified asphalt, aggregate basalt and limestone mineral filler. The optimum asphalt-aggregate ratio was 5.2%. The dynamic modulus decay and the Residual Strength decay were termed as the damage variables to evaluate the fatigue damage process of asphalt mixtures, respectively. Based on the test results, the decay patterns of the dynamic modulus and the Residual Strength during fatigue tests under different stress states were revealed, and the model and the parameters of fatigue damage according to the corresponding decay patterns were obtained. Then, based on the assumption that the Residual Strength and dynamic modulus depend on the same damage state, the relationship between the two damage definitions was given, and the Residual Strength-dynamic modulus coupled model was established. The results showed that the Residual Strength-dynamic modulus coupled model could better describe the fatigue damage evolution law of asphalt mixture, and the parameter of this coupled model could be obtained by less Residual Strength tests. A modified formula for calculating the damage variables associated with Residual Strength and dynamic modulus was proposed based on the relationship between two kinds of damage variables.
Hongfu Liu - One of the best experts on this subject based on the ideXlab platform.
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nonlinear fatigue damage model of asphalt mixture based on dynamic modulus and Residual Strength decay
Materials, 2019Co-Authors: Hongfu Liu, Xinyu Yang, Chengdong Xia, Jianlong Zheng, Tuo HuangAbstract:In order to describe the fatigue damage state of asphalt mixture more reasonably, direct tensile tests of the fatigue and the Residual Strength under stress levels of 1.00 MPa, 0.50 MPa and 0.25 MPa with five parallel tests were carried out. The trabecular specimens of AC-13C asphalt mixture (25 cm × 5 cm × 5 cm) were manufactured with Styrene-Butadiene-Styrene (SBS) modified asphalt, aggregate basalt and limestone mineral filler. The optimum asphalt-aggregate ratio was 5.2%. The dynamic modulus decay and the Residual Strength decay were termed as the damage variables to evaluate the fatigue damage process of asphalt mixtures, respectively. Based on the test results, the decay patterns of the dynamic modulus and the Residual Strength during fatigue tests under different stress states were revealed, and the model and the parameters of fatigue damage according to the corresponding decay patterns were obtained. Then, based on the assumption that the Residual Strength and dynamic modulus depend on the same damage state, the relationship between the two damage definitions was given, and the Residual Strength-dynamic modulus coupled model was established. The results showed that the Residual Strength-dynamic modulus coupled model could better describe the fatigue damage evolution law of asphalt mixture, and the parameter of this coupled model could be obtained by less Residual Strength tests. A modified formula for calculating the damage variables associated with Residual Strength and dynamic modulus was proposed based on the relationship between two kinds of damage variables.
Sp G Pantelakis - One of the best experts on this subject based on the ideXlab platform.
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fatigue damage accumulation and Residual Strength assessment of cfrp laminates
Composite Structures, 2004Co-Authors: K I Tserpes, P Papanikos, G Labeas, Sp G PantelakisAbstract:The method of progressive damage modelling has been used to assess fatigue damage accumulation and Residual Strength of carbon-fibre reinforced plastic (CFRP) laminates under fully reversed cyclic loading (R=σmin/σmax=−1). The accumulation of different damage modes has been assessed, as a function of number of cycles, using a three-dimensional fatigue progressive damage model (FPDM). The Residual Strength of the CFRP laminates has been assessed through the combined use of the FPDM with a static three-dimensional progressive damage model (PDM). By simulating the experimental procedure, the FPDM has been applied up to certain number of cycles, to estimate the accumulated fatigue damage and then, the static PDM has been applied (quasi-static tensile loading) to predict final tensile failure of the laminates, which corresponds to the Residual Strength of the laminate, after it has been exposed at the specific cycles. The models comprised the components of stress analysis performed using finite elements, failure analysis performed using polynomial stress-based failure criteria and material property degradation performed using degradation rules. The analysis has been validated experimentally (a) by assuming a laminate free of internal defects, and (b) by considering the initial defects, which were determined experimentally for certain laminates. The analysis has resulted in an accurate simulation of the experimentally determined fatigue damage accumulation and Residual Strength.
Jenn-ming Yang - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Residual Strength of notched fiber metal laminates
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2007Co-Authors: Y. Tan, Jenn-ming YangAbstract:Fiber metal laminates (FML) are a family of hybrid materials consisting of alternating layers of thin metal sheets and fiber-reinforced epoxy prepregs. In contrast to aluminum alloys, the presence of notches in FML causes significant Strength reductions. The objective of this study was to evaluate the Residual Strength of fiber-reinforced metal laminates with a circular open hole. Mechanical testing was performed to determine the unnotched tensile properties and notched Strength of bi-directionally reinforced fiber metal laminates. The influence of specimen dimension and notch size on Residual Strength and notch sensitivity of fiber metal laminates was investigated. A modified point stress criterion was introduced to predict the Residual Strength of fiber metal laminates with open hole. An excellent agreement between experimental results and model prediction was obtained. The Residual Strength predicted from this modified model also correlated very well with the experimental data in the literature for various other types of fiber metal laminates. A computer simulation based on finite element method was performed to study stress concentration and stress concentration around notch. Failure modes, damage initiation and progression of notched fiber metal laminates are also characterized and discussed.
