聚氨酯聚酰胺复合隔热铝合金型材抗弯性能研究

Research on the flexural performance of polyurethane polyamide composite heat-insulating aluminum alloy profiles

针对聚氨酯聚酰胺复合隔热铝合金型材(复合隔热铝合金型材)截面特点,考虑了隔热型材自身刚度对复合隔热铝合金型材截面整体力学特性的影响,得到了复合隔热铝合金型材截面等效惯性矩计算公式,并通过有限元模拟和抗弯性能试验,验证了等效截面抗弯刚度理论的适用性与合理性。结果表明:在型材整体弹性变形范围内,等效截面抗弯刚度理论计算值、试验值与有限元模拟值的一致性良好;复合隔热铝合金型材弹性模量约为1360 MPa;复合隔热铝合金型材延性较差,发生非线性变形后,型材很快发生脆性断裂;等效抗弯刚度理论仅适用于复合隔热铝合金型材线弹性阶段截面力学性能分析,对于非线性计算分析等效抗弯刚度理论不再适用。

According to the cross-sectional characteristics of polyurethane polyamide composite heat-insulated aluminum alloy profiles,the influence of the stiffness of the heat-insulated profiles on the overall mechanical properties of the composite heat-insulated aluminum alloy profiles is considered.The calculation formula of the equivalent moment of inertia of the composite heat-insulated aluminum alloy profiles is obtained,and the applicability and rationality of the theory of the bending stiffness of the equivalent cross-section are verified by finite element simulation and bending performance test.The results show that:The calculated value of the revised theoretical formula,the experimental value and the simulated value of the finite element have a pretty consistency in the range of the overall elastic deformation of the profile.The elastic modulus of the composite heat-insulated profiles is 1360 MPa.The ductility of polyurethane polyamide composite heat-insulating aluminum alloy profiles is poor,and brittle fracture occurs quickly in the profiles when nonlinear deformation happen.The equivalent bending stiffness theory is only applicable to the mechanical performance analysis of composite insulation profiles in the linear elastic stage section,and is no longer applicable for nonlinear calculation analysis.