排序方式: 共有34条查询结果,搜索用时 15 毫秒
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通过ANSYS软件二次开发将MJS随动强化模型嵌入到执行程序.利用有限元方法,对受面内循环弯矩的内压斜接管结构进行循环塑性分析.计算结果表明,在一定载荷作用下,斜接管根部的锐角侧有较大的塑性应变累积,且塑性应变区域随加载次数增加而增大.分析发现,最大棘轮应变点的棘轮应变沿多个方向发生,第一主应变方向位于纵向对称面内,棘... 相似文献
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多轴棘轮加载时轴向加载的恒定应力、剪切应变幅对轴向棘轮应变和疲劳寿命有很大的影响.考虑棘轮效应影响的Coffin模型将棘轮效应与循环部分相结合来计算疲劳寿命,预测结果较好,绝大部分预测结果分布在2倍分散带内. 相似文献
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The effect of thermal cycling on the state of residual stress in thermoviscoelastic polymeric materials bonded to stiff elastic substrates was investigated using numerical techniques, including finite element methods. The work explored the relationship between a cyclic temperature environment, temperature-dependent viscoelastic behavior of polymers, and thermal stresses induced in a bimaterial system. Due to the complexity of developing a closed-form solution for a system with time- and temperature-dependent material properties, and time-varying temperature and coupled boundary conditions, numerical techniques were used to acquire approximate solutions.
The results indicate that residual stresses in an elastic-viscoelastic bimaterial system incrementally shift over time when subjected to thermal cycling. Potentially damaging tensile axial and peel stresses develop over time as a result of viscoelastic response to thermal stresses induced in the polymeric layer. The applied strain energy release rate at the ends of layered or sandwich specimens is shown to increase as axial stress develops. The rate of these changes is dependent upon the thermal cycling profile and the adhesive's thermo-mechancial response. Discussion of the results focuses on the possiblility that the increasing tensile residual stresses induced in an adhesive bond subjected by thermal cycling may lead to damage and debonding, thus reducing bond durability. 相似文献
The results indicate that residual stresses in an elastic-viscoelastic bimaterial system incrementally shift over time when subjected to thermal cycling. Potentially damaging tensile axial and peel stresses develop over time as a result of viscoelastic response to thermal stresses induced in the polymeric layer. The applied strain energy release rate at the ends of layered or sandwich specimens is shown to increase as axial stress develops. The rate of these changes is dependent upon the thermal cycling profile and the adhesive's thermo-mechancial response. Discussion of the results focuses on the possiblility that the increasing tensile residual stresses induced in an adhesive bond subjected by thermal cycling may lead to damage and debonding, thus reducing bond durability. 相似文献
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Experimental observations are reported for the non-proportional multiaxial transformation ratchetting of super-elastic NiTi shape memory alloy performed under the stress-controlled cyclic tension–torsion loading conditions and at room temperature. The effect of axial mean stress on the evolutions of transformation ratchetting strain and dissipation energy per cycle during the cyclic tests is discussed firstly; and then the dependence of multiaxial transformation ratchetting on the different non-proportionally loading paths (e.g., linear, square, hourglass-typed, butterfly-typed, rhombic and octagonal paths) is investigated. The results show that the multiaxial transformation ratchetting occurs mainly in the axial direction because only the non-zero axial mean stress is used and the mean shear stress is set to be zero in the all prescribed multiaxial loading paths; and the axial peak and valley strains increase with the increasing axial mean stress and also depend significantly on the shapes of loading paths. Comparison with the corresponding uniaxial ones illustrates that the multiaxial stress states are more helpful to promote the development of transformation ratchetting, especially for the non-proportional ones. 相似文献
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Y. ZHU G. KANG J. DING M. ZHU 《Fatigue & Fracture of Engineering Materials & Structures》2013,36(2):127-138
Based on the finite element simulation, the crack nucleation location and failure life of bending fretting fatigue are analysed and predicted for LZ50 axle steel, respectively. In the simulation, a simplified two‐dimensional finite element model with an equivalent normal force is proposed and the role of ratchetting is also considered by using a new cyclic elastoplastic constitutive model. The crack nucleation location and fatigue life are finally predicted by Smith–Watson–Topper (SWT) critical plane criteria referring to the finite element calculation. It is shown that the predicted results are in fairly good agreement with the experimental ones. 相似文献
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Haofeng Chen Alan R. S. Ponter 《International journal for numerical methods in engineering》2006,68(1):13-32
On the basis of the previously proposed Linear Matching Method (LMM), a new LMM model and its corresponding numerical procedure are developed in this paper to allow for the evaluation of plastic, creep and ratchet strains of structures subjected to a general load condition in the steady cyclic state. The constant and varying residual stress fields associated with differing mechanisms are obtained as well as the steady cyclic stress state of the whole component for further structural design and assessment. The total strain range for use in fatigue assessment, including the effect of creep and plastic strains, is obtained. A typical example of 3D holed plate subjected to cyclic thermal load and constant mechanical load is analysed here in detail to verify the applicability of the proposed numerical technique. The LMM results in the paper are compared with those obtained by ABAQUS step‐by‐step inelastic analyses. This comparison demonstrates that the LMM has both the advantage of programming method and the capacity to be implemented easily within a commercial finite element code, in this case ABAQUS. The LMM provides a general‐purpose technique for the evaluation of creep/fatigue interaction in the steady cyclic state. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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