Hysteretic Beam Finite-Element Model Including Multiaxial Yield/Capacity Surface Evolution with Degradations
Hysteretic Beam Finite-Element Model Including Multiaxial Yield/Capacity Surface Evolution with Degradations
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DOI：
10.1061/(asce)em.1943-7889.0001767
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发表时间：
2020-09-01
影响因子：
3.3
通讯作者：
Warn, G. P.
中科院分区：
文献类型：
--
作者：
Amir, M.;Papakonstantinou, K. G.;Warn, G. P.
一个多轴退化滞回模型的开发，使一致的多轴屈服/能力面退化的演变，并适当地纳入到一个有限元框架中使用滞回梁单元。退化现象中引入了对称或不对称的强度退化，刚度退化，捏功能，及其各种组合的形式在这个模型中。更具体地说，一个新的强度退化函数的开发和增强在其他现有的功能，建议模拟物理观察到的退化现象的结构元件。然后在多轴经典损伤塑性框架中采用退化函数来满足屈服/承载力面的一致性准则，从而得到一组新的多轴滞回演化方程。所提出的演化方程是专门制定的，以便他们可以无缝地纳入一个滞后有限元公式，使用适当的位移和滞后插值函数，以满足精确的平衡条件和模型分布塑性特性，从而避免任何剪切锁定效应。因此，建议的滞回有限元模型占平衡，分布塑性，退化，多轴非弹性与能力的相互作用，在一个单一的一致和统一的框架。常数系统矩阵，不需要在整个分析过程中更新，而退化和非弹性捕获通过建议的多轴滞回演化方程。一个有效的数值求解方案也被设计出来，其中的有限元模型可以明确地表示在一阶常微分方程（ODE），而不是一组复杂的微分代数方程的准静态的情况下。然后，可以使用任何标准ODE求解器直接求解所得到的方程组，而无需任何所需的线性化。数值例子和实验验证，以证明所提出的方法的性能和实用性。(c)2020年美国土木工程师协会
A multiaxial degrading hysteretic model is developed, enabling consistent multiaxial yield/capacity surface evolution with degradations, and is appropriately incorporated in a finite-element framework using hysteretic Timoshenko beam elements. Degradation phenomena are introduced in this model in the form of either symmetric or asymmetric strength degradation, stiffness degradation, pinching functions, and various combinations thereof. More specifically, a new strength degradation function is developed and enhancements in other existing functions are suggested to simulate the physically observed degradation phenomena in structural elements. The degradation functions are then employed in a multiaxial classical damage-plasticity framework to satisfy the consistency criterion of the yield/capacity surface, thereby resulting in a set of new multiaxial hysteretic evolution equations. The proposed evolution equations are specifically formulated so as they could be seamlessly incorporated into a hysteretic finite-element formulation, using appropriate displacement and hysteretic interpolation functions, to satisfy the exact equilibrium conditions and model distributed plasticity characteristics, thereby avoiding any shear locking effects. As such, the proposed hysteretic finite-element model accounts for equilibrium, distributed plasticity, degradations, and multiaxial inelasticity with capacity interactions in a single consistent and unified framework. Constant system matrices are employed that do not require updating throughout the analysis, while the degradations and inelasticity are captured through the suggested multiaxial hysteretic evolution equations. An efficient numerical solution scheme is also devised, where the finite-element model can be expressed explicitly in terms of first order ordinary differential equations (ODEs), rather than a set of complex differential-algebraic equations for quasi-static cases. The resulting system of equations can be then straightforwardly solved using any standard ODE solver, without any required linearization. Numerical illustrations and experimental verifications are provided to demonstrate the performance and utility of the suggested methodology. (c) 2020 American Society of Civil Engineers.