PTFE膜材力学性能及抗力不定性分析

Mechanical Properties and Resistance Uncertainty of PTFE Membrane Material

关键词:  PTFE（聚四氟乙烯）膜材  破坏机理  抗力不定性  损伤

Key words:  PTFE membrane material  failure mechanism  resistance uncertainty  damage

摘要:

对PTFE膜材的基本力学性能进行了试验研究，分析了膜材的拉伸破坏机理；进行了膜材的抗力不定性分析，研究了循环拉伸、温度、损伤、接缝连接、人工加速老化等对PTFE膜材拉伸性能的影响规律.结果表明：膜材的经向断裂延伸率小于纬向断裂延伸率，经向抗拉强度略大于纬向抗拉强度；随着温度的升高，膜材拉伸强度逐渐减小；不同温度下搭接膜材接缝拉伸强度能够达到母材拉伸强度的90%以上；损伤膜材的拉伸强度有明显的折减，折减程度同取样位置、折叠次数有直接关系；循环应力幅较大时，经循环拉伸后的膜材拉伸曲线更接近线性；人工加速老化使膜材的拉伸强度有一定程度的折减，但并不明显.

Abstract:

A series of tests were carried out to study the mechanical properties of PTFE membrane material. The tensile failure mechanisms of PTFE membrane material were discussed, and the resistance uncertainty of PTFE membrane material was analyzed. The effects of cyclic tensile, temperature, damage, welding connection, artificial accelerated aging on the material tensile properties were studied. Results show that the strain at break in warp is less than that in weft and the tensile strength in warp is slightly higher than the tensile strength in weft. With temperature increasing, the tensile strength of membrane material decreases. The tensile strength of seams of welding membrane material can achieve 90% of that of base material. There is significant reduction of tensile strength, of which the degree is related to the sample position and folding times. When the stress amplitude of cyclic tensile tests is higher, the tensile curves of PTFE membrane material after cyclic tensile tend to be linear. The accelerated aging can lead to the decreasing to PTFE membrane material tensile strength, of which the degree is not obvious.