Effect of Temperature and Humidity on Indentation Property of Polymethacrylimide (PMI) Foam Core Sandwich Structures

摘要

Sandwich structures may experience wide range of varying temperature and humidity conditions (e.g., in aerospace and marine applications). However, effect on especially the complex polymer-based foam core materials is still rather poorly known. Therefore, influence of the temperature and humidity on the mechanical behavior of polymethacrylimide (PMI) closed cell foam core material and its sandwich structure applications are studied. Focus is on the hygrothermal effect on the deformation mechanism of PMI foam core material under quasi-static loading and consequently the effect on indentation loading behavior of sandwich structures having same core material. Elastic and plastic deformation of foam core specimens is observed under uniaxial loading and the effect of hygrothermal environment on the material properties and stress-strain behavior is studied. Simulations of the indentation loading response of foam core sandwich structure under various temperature and humidity conditions are conducted by utilizing the experimentally obtained information of the hygrothermal behavior of the foam core material. Indentation behavior of sandwich structures predicted by simulations are finally compared with experimental results to verify the effect of hygrothermal conditions. From these tests it can be seen that humidity has more significant effect than temperature on the indentation property of the sandwich structures at temperature conditions ranging from 30°C to 80 °C.