Researcher(s)
- Hayden Marquard, Chemical Engineering, University of Delaware
Faculty Mentor(s)
- Sagar Doshi, University of Delaware Center for Composite Materials, University of Delaware
Abstract
Epoxy resin-based composites are used in the automotive industry due to their low weight, strength, and resistance to environmental conditions. When impacted, delamination occurs leading to stiffness loss and degradation of mechanical properties. To improve resistance to interlaminar failures in the composite, interlayer toughening is utilized to reduce shear stresses through decoupling of plies increasing delamination resistance. At extreme ends of the operating temperature range (-55°C and 76°C), the mechanical properties of current interlayer toughening materials change, leading to deterioration in performance. At -55°C, the interlayer loses ductility as it is below the glass transition temperature and an adhesive failure is observed. At high temperatures, the interlayer fails due to softening.
This study investigates the use of different interlayers by evaluating the peel strength. The environmental conditions follow that of the definition by the DoD MIL-STD-810G. Tests are performed showing extreme temperature and baseline performances for the interlayers. Failure modes and mechanisms are studied by evaluating the failed specimens using microscopy. The durability and damage tolerance of epoxy resin-based composites can be improved by optimizing processing conditions, characterizing different interlayer materials, and determining an improved interlayer at extreme operating temperature conditions.