The Experts below are selected from a list of 177 Experts worldwide ranked by ideXlab platform
Tomonaga Okabe - One of the best experts on this subject based on the ideXlab platform.
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Microstructure-dependent Fatigue Damage Process in short fiber reinforced plastics
International Journal of Solids and Structures, 2010Co-Authors: Masaaki Nishikawa, Tomonaga OkabeAbstract:This paper proposes a numerical model of the Fatigue Damage Process in short fiber-reinforced plastics. In the Fatigue fracture of these composites, the microcracks in the polymer matrix increase with Fatigue cycles and dominate the Fatigue Damage Process. Therefore the matrix crack was modeled by the continuum Damage mechanics approach while considering the microscopic Fatigue Damage Process in the polymer matrix based on a Kachanov-type Damage-evolution law. We applied the model to addressing the Fatigue-cycle experiments of short glass-fiber reinforced polycarbonate conducted by Ha et al. The simulated results agreed well with the experimental results. Moreover, the simulation revealed that the dependence of the Damage accumulation on the fiber orientation remarkably changes the Fatigue life of the short glass-fiber reinforced plastics.
Martin Fehlbier - One of the best experts on this subject based on the ideXlab platform.
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on the role of internal defects in the Fatigue Damage Process of a cast al si cu alloy
International Journal of Fatigue, 2018Co-Authors: Angelika Bruecknerfoit, M Luetje, I Bacaicoa, A Geisert, Marcel Wicke, Martin FehlbierAbstract:Abstract The effect of shrinkage pores and gas pores on the Fatigue Process of a secondary Al-Si-Cu-Fe alloy was analyzed by micro-computed tomography and scanning electron microscopy. Repeated CT-scans were performed in order to study the Damage accumulation Process. It was found that there are basically three different failure scenarios. In the first one, lifetime is determined by cracking of the dendritic branches bridging extended pores. This Damage Process will happen even at moderate load levels as these material bridges are exposed to high local loads. Lifetime in the second case is dominated by crack initiation from complex shaped gas pores followed by a short period of stable crack growth. Crack coalescence then becomes very likely, and failure is imminent. Finally, a two-stage crack growth Process was observed for complex shaped shrinkage: fracture of the material bridges is followed by a phase of stable crack extension with the Fatigue crack starting from one or several branches of the shrinkage pore. Estimate of the crack growth rate agree with previous results from the literature and confirm that the internal cracks grow much faster than expected long crack vacuum tests.
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on the role of internal defects in the Fatigue Damage Process of a cast al si cu alloy
Procedia structural integrity, 2017Co-Authors: Angelika Bruecknerfoit, M Luetje, I Bacaicoa, A Geisert, Martin FehlbierAbstract:Abstract The effect of different types of defects on the Fatigue properties of a secondary Al-Si-Cu-Fe alloy was analyzed by micro-computed tomography and scanning electron microscopy. It was found that extended pores typically occurring at unfavourable cooling conditions possess several regions of similar stress concentration and hence multiple crack initiation is very likely. On the other hand, the Fe-rich inclusions may form impressive clusters and can contribute significantly to deteriorating the tensile properties of the material. However, they do not directly influence the Fatigue properties in as cast specimens, as they are virtually absent in the casting skin. However, they may be relevant in pore formation as CT scans show that large pores can be enclosed in the cavities of the iron inclusion clusters.
Masaaki Nishikawa - One of the best experts on this subject based on the ideXlab platform.
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Microstructure-dependent Fatigue Damage Process in short fiber reinforced plastics
International Journal of Solids and Structures, 2010Co-Authors: Masaaki Nishikawa, Tomonaga OkabeAbstract:This paper proposes a numerical model of the Fatigue Damage Process in short fiber-reinforced plastics. In the Fatigue fracture of these composites, the microcracks in the polymer matrix increase with Fatigue cycles and dominate the Fatigue Damage Process. Therefore the matrix crack was modeled by the continuum Damage mechanics approach while considering the microscopic Fatigue Damage Process in the polymer matrix based on a Kachanov-type Damage-evolution law. We applied the model to addressing the Fatigue-cycle experiments of short glass-fiber reinforced polycarbonate conducted by Ha et al. The simulated results agreed well with the experimental results. Moreover, the simulation revealed that the dependence of the Damage accumulation on the fiber orientation remarkably changes the Fatigue life of the short glass-fiber reinforced plastics.
Wang Zhenlin - One of the best experts on this subject based on the ideXlab platform.
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a new approach to low cycle Fatigue Damage based on exhaustion of static toughness and dissipation of cyclic plastic strain energy during Fatigue
International Journal of Fatigue, 2001Co-Authors: Ye Duyi, Wang ZhenlinAbstract:Experimental results show that the static toughness synthesizing both strength and plasticity of a material is a mechanical property parameter sensitive to the Fatigue Damage Process. The reduction of the static toughness in the Fatigue Damage Process indicates the progressive exhaustion of the ability to absorb energy inherent in the material due to Fatigue Damage evolution, which is associated directly with the irreversible Process of energy dissipation of Fatigue failure. Based on the exhaustion of the static toughness and dissipation of the plastic strain energy during Fatigue failure, a Damage variable that is consistent with the Fatigue Damage mechanism, sensitive to the Fatigue Damage Process and can be measured with a simple experimental procedure is defined in this paper. A corresponding Fatigue Damage evolution equation is derived by connecting the Damage variable with the static toughness exhaustion during Fatigue, which is further examined in both theory and experiment. A Fatigue Damage accumulation formula that has the capacity of predicting the load sequencing effect correctly and can be applied very conveniently in engineering practice is further deduced by using equivalent-loading postulate. A comparison of experimental data with the predictions shows excellent agreement for two-stage cyclic tests.
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.
