纺织物下垂变形数值计算

利用共旋技术提出了一个高柔性梁(布条)大位移大转动计算模型,通过把纺织物沿经向和纬向离散成许多布条,建立了纺织物下垂变形模型,模型仅使用了节点平移自由度而没有使用转动自由度,并采用了一种单元应变能积分格式,模型考虑了纺织物面内拉伸、面内剪切以及弯曲;提出了一种控制单步全Newton-Raphson迭代格式步长的方法来确保得到控制方程组的收敛解.数值算例表明模型能够较精确地预测纺织物的最终下垂形状.

DRAPE DEFORMATION ANALYSIS OF WOVEN FABRIC

By using the co rotational technique, a numerical model is proposed to simulate large displacement and large rotation deformations of initially straight flexible beams, or fabric strips. By discertizing fabric sheet into many fabric strips lying in the warp and weft directions, a fabric drape deformation analysis model is then developed. Only the nodal translation d.o.f.s are assumed in the model, and the rotational d.o.f.s are not required. A new element integration scheme is used. The effects of in plane stretch, in plane shear and the bending of the fabric are all taken into account in the model. A technique which can control the iteration step length of the single step full Newton Raphson method is presented to get the converged solution. Numerical examples show that the model can predict the drape deformation of fabric sheet with good accuracy.