基于ABAQUS的木材本构模型及试验验证

CONSTITUTIVE MODEL OF WOOD BASED ON ABAQUS AND ITS TEST VERIFICATION

  • 摘要: 层板胶合木的制作流程决定了其材料性能与组胚粘结的层板木材的力学性能有着密切联系。基于木材材性试验,以樟子松为研究对象,建立了便于工程应用的木材本构模型。在弹性阶段,将木材应力-应变关系按正交各向异性及横观各向同性建模;选择Yamada-Sun强度准则及简化的Hashin强度准则作为木材屈服的判定依据;以正则化假设和一致性条件描述木材塑性发展的流动法则,采用弹塑性回退映射算法,将应力点约束在屈服面上;通过引入连续损伤因子,对应力折减模拟木材在拉、剪作用下发生脆性破坏;采用Ziegler随动硬化模型,控制屈服面的转移实现木材受压屈服后的应变硬化。编写用户材料子程序将木材本构模型嵌入ABAQUS中,并开展了胶合木梁柱节点试验与精细化有限元数值分析,试验结果与模拟结果吻合良好。分析结果表明:清材小试件材性试验和胶合木梁柱节点转动试验有限元模型可以有效地描述木材受压硬化、拉剪损伤演化,及节点受力非线性行为,验证了该文建立的木材本构模型的有效性。

     

    Abstract: The manufacturing process of glulam determines that its material properties are closely related to the laminated wood. Based on wood material test, the Mongolian pine was used as the research object. This paper established a material constitutive model for numerical analysis of wood, which is convenient for engineering applications. In elastic phase, the stress-strain relationship of wood was modeled as orthotropic and transversely isotropic. Yamada-Sun criterion and modified Hashin criteria were used for judging the yield of wood. The flow rule describing plastic development of wood was derived according to regularization hypothesis and consistency condition. The stress point was constrained on the yield surface by using the return mapping algorithm. The continuous damage factor was introduced to reduce the stress to simulate the brittle failure of wood under tension and shear. Strain hardening under compression after the yield of wood was modeled by controlling the transition of yield surface based on Ziegler kinematic hardening model. A user-defined subroutine including the material constitutive model of wood was implemented into ABAQUS. Experimental study and refined finite element analysis on the performance of beam-column glulam joints were carried out. The FEM analysis is in good agreement with the experimental results. Analysis results show that the finite element models of material test on small clear specimens of wood and rotation test on beam-column glulam joint can effectively describe the hardening under compression and damage evolution under tension and shear of wood, as well as the nonlinear behavior of joint, which verifies the constitutive model of wood proposed in this paper.

     

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