金属复合屋面板用硬质聚氨酯泡沫的力学性能

Mechanical Properties of Rigid Polyurethane Foam Used in Metal Composite Roof Panels

针对金属复合屋面板用硬质聚氨酯泡沫材料分别进行了发泡方向和涂层方向的拉伸、压缩力学性能试验,对各向基本力学参数进行了测定.结果表明:硬质聚氨酯泡沫材料在发泡方向和涂层方向的拉伸和压缩力学性能不相同,不能简单看作为各向同性材料.在拉伸情况下,硬质聚氨酯泡沫材料呈脆性破坏,但压缩时存在明显屈服平台且无明显破坏特征.硬质聚氨酯泡沫材料发泡方向与涂层方向的力学参数差异明显,其发泡方向的拉、压弹性模量仅约为涂层方向的1/2,拉伸极限强度及压缩屈服强度也都明显低于涂层方向.根据试验数据,建议了适用于硬质聚氨酯泡沫的横观各向同性本构模型并对主要参数进行了拟合.

For the rigid polyurethane foam used in metal composite roof panels, tensile and compression tests were carried out in its foaming and coating directions respectively, and basic mechanical parameters in those characteristic directions were obtained. The results reveal that the rigid polyurethane foam cannot be regarded as isotropic material due to the differences of the tensile and compressive behaviors between the foaming direction and the coating direction. Brittle fracture occurs in the tensile testing. However, there are yield platform and lack of damage in the compressive case. The mechanical parameters of the rigid pol- yurethane foam in the foaming direction and the coating direction are also different. The tensile and com- pressive elastic moduli in the foaming direction are only half of those in the coating direction, while the tensile ultimate strength and compression yield strength in the foaming direction are also less than that in the coating direction. Based on the data in test, a transversely isotropic constitutive model suitable for the rigid polyurethane foam is suggested and main parameters of the model are fitted in the end.