Numerical simulation of mechanical behaviour of wood under complex stress
Numerical simulation of mechanical behaviour of wood under complex stress
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发表时间：
2011
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通讯作者：
Pan Jing-long
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作者：
Pan Jing-long
建立了适用于结构有限元模拟的木材本构模型，该模型中木材为正交各向异性弹性体，具有不同的压缩和拉伸强度;木材在拉伸或剪切下表现出脆性破坏，用正交各向异性对称理论描述了弹性应力与应变的关系，用Yamada-Sun准则来判断木材在压缩和应变下的屈服。木材在拉伸和剪切中的软化。应变-通过引入损伤因子和弹性应变能，建立了木材软化模型，根据塑性一致性条件，由屈服函数推导出流动法则，通过控制屈服面从初始屈服面过渡到屈服面，模拟了木材横纹压缩的应变硬化和二次应变硬化，得到了木材软化的力学模型。编制了用户自定义子程序VUMAT，将木材的本构模型导入ABAQUS，建立了木材的压缩和拉伸（包括拉伸和压缩）的有限元模型，通过与试验结果和Hankinson强度理论的比较，验证了木材本构关系和有限元模型的正确性。
A constitutive model of wood suitable for FE modeling of the structures was developed.In the model,wood is orthotropically elastic with different strengths in compression and tension;wood exhibits brittle failure under tension or shear,but yields under compression.The orthotropic symmetry theory was employed to express the relationship between elastic stress and strain.Yamada-Sun criterion was used to judge yield of wood in compression and strain-softening of wood in tension and shear.The strain-softening model of wood was established by introducing the damage factor and the elastic strain energy.The flow rule was derived by yield function according to plastic consistency condition.The strain hardening and the secondary strain hardening of compression perpendicular to grain were modeled by controlling the transition of yield surface from initial yield surface to ultimate yield surface.A user-defined subroutine VUMAT was encoded to include the material constitutive model of wood into ABAQUS,and two FE models were developed to simulate the behaviour of wood in compression and tension,including tension and compression at angle to grain.The constitutive relationship and the FE model were validated by comparison of the numerical results with experimental results and Hankinson strength theory of wood.