Abstract
This study focuses on short-term thermal degradation of polymer matrix composites by one-sided impact of improvised incendiary devices (IID). Specimens of two commercial composites HexPly® 8552/IM7 and M18-1/G939 with various thicknesses (1–8 mm) are systematically investigated as well as sandwich structures thereof, applying various amounts of fire accelerant predominantly in laboratory scale fire tests. Results of preceding large-scale fire tests with IIDs justify the chosen conditions for the laboratory-scale fire tests. The aim is to correlate the amount of fire accelerant with heat damage and residual mechanical strength. Thermal damage is characterized visually and by ultrasonic testing, infrared spectroscopy, and residual interlaminar shear strength. Matrix degradation and combustion only contribute to the overall amount of released heat by the fire accelerant for thin and especially vertically aligned panels as tested by a cone calorimeter (without electrical heating), but not for horizontally orientated and thicker panels. Degradation processes are discussed in detail. Protective effects are observed for typical coatings, a copper mesh applied for protection against lightning strike, combinations thereof as well as an intumescent coating. Especially sandwich structures are prone to severe damage by assaults with IID, such as Molotov cocktails.
Highlights
Improvised incendiary devices (IID) have been used for a long time especially by terrorists, as they are cheap and easy to prepare [1,2,3,4]
This study focuses on short-term thermal degradation of Carbon fiber-reinforced polymers (CFRP) by the influence of liquid fire accelerants
It is the goal of this work to assess how CFRP structures used in defense industry are prone to failure due to assaults by improvised incendiary devices
Summary
Improvised incendiary devices (IID) have been used for a long time especially by terrorists, as they are cheap and easy to prepare [1,2,3,4]. Knowledge about the relation between input of thermal energy, degradation of the polymer matrix, and the loss of mechanical strength of composite materials is of wide interest, especially in aircraft industry. In previous studies [15,16,17] an empirical correlation was established between the degradation of the polymer matrix traced by infrared spectroscopy and the residual mechanical strength for the investigated CFRP HexPly® 8552/IM7 and M181/G939. With respect to the intumescent coating, differences of protection efficiency is compared for heat impact by irradiation and improvised fire accelerants It is the goal of this work to assess how CFRP structures used in defense industry are prone to failure due to assaults by improvised incendiary devices. The aim is to correlate the amount of applied thermal energy with heat damage, to assess detectability of the damage and to predict residual mechanical strength
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
