Approaches to understand and predict the influence of rapid heat-up on degradation and strength of carbon fibre polymer matrix composites

Abstract

This study focuses on understanding and prediction of short-term thermal degradation of polymer matrix composites. One sided irradiation of two commercial composites (HexPly® 8552/IM7 and M18-1/G939) is carried out on specimens of various thickness (2, 4, 6 mm) at different heat fluxes (50 and 80 kW/m2) for various exposure times prior to ignition. The aim is to correlate the amount of the applied thermal energy with the heat damage and the residual mechanical strength. Among the two primary components of each matrix the epoxy resin is observed to degrade faster than the thermoplastic under thermal load, as measured by IR spectroscopy. A correlation is achieved between the interlaminar shear strengths and the relative amount of the residual matrix components. The interlaminar shear strengths and degradation processes are assessed in dependence of the applied energy per volume. The derived relationships and a chemometric analysis of IR spectra, can be used to rapidly estimate mechanical properties, as well as other properties of specimens with unknown thermal preload. Degradation processes are discussed in detail.

Thermoplastic Pultrusion: A Review

“…Long-term aging of composite material at a temperature below melting causes a change in glass transition temperature and strength [ 247 , 248 ]. During short-term aging, thermoplastic composite is sharply heated to thermal decomposition temperature; thus, rapid decrease in tensile and interlaminar shear strength is observed [ 249 , 250 ]. Apart from debonding and cracks, delamination and fiber failures can occur [ 251 , 252 ].…”

Time to failure modeling of carbon fiber reinforced polymer composites subject to simultaneous tension and one-sided heat flux

“…1 However, polymer composite properties are heavily dependent upon the environment in which they operate and thus are susceptible to degradation at high temperatures and when exposed to fire. 1–38 Therefore, accurate thermal property characterization and behavior modeling for composites is critically important.…”

“…One typical focus of this research is on the resultant mechanical properties following high temperature exposure. 1–9 The effects of thermal degradation are also observed by measuring physical changes such as mass loss, delamination, or material surface deformation. 10–16 Further studies have focused on cyclic thermal loading 17,18 and accelerated thermal aging of composites.…”

Effects of simultaneous compression and one-sided heat flux on the time to failure of carbon fiber-reinforced polymer composites

“…One typical focus of this research is on the resultant mechanical properties following high-temperature exposure. 1–7 The effects of thermal degradation are also observed by measuring physical changes such as mass loss, delamination, or material surface deformation. 8–12 Further studies have focused on cyclic thermal loading 13,14 and accelerated thermal aging of composites, 15 each revealing different effects of thermal degradation.…”

“…However, polymer properties are highly susceptible to degradation at high temperatures, posing significant disadvantages in extreme environments. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] This is especially important within structural applications where materials can be exposed to fire while supporting simultaneous mechanical loads. In these cases, components can fail as the thermal load reduces the mechanical properties of the material over time.…”