• Wisnom, Michael
• Jalalvand, Meisam
• Fotouhi, Mohammad
• Prato, Alessia

Abstract

Low velocity impacts on composite laminates can cause a significant amount of delamination that is oftenreferredtoasbarelyvisibleimpactdamage(BVID).Thisdamagecancausesignificant degradation of structural properties, especially the compressive strength after impact. The aim of this workwastoutilisethinplycarbon/glasshybridlaminatestoactivatenewtypesofdamage mechanismsunderindentation(quasi-staticimpact)thataremoregradualandeasiertodetect. Therefore, 3 different types of hybrid composite plates fabricated from novel hybrid architectures of thin ply high modulus carbon (HS40) and standard thickness S-glass laminates were investigated. For comparison,alaminatecontainingonlyS-glassplieswasinvestigatedaswell. Theinvestigated specimens were interrupted at different load-levels and a detailed assessment of the damage evolution was carried out using X-ray Computed Tomography (CT). For all the hybrid configurations, a larger damage area was observed mostly under the indenter and the delaminations were smaller in the middle plies compared to the upper plies. In contrast, for the Glass laminates the delaminations were larger in the middle plies compared to the upper plies. For the hybrid laminates, the percentage of the first load dropintheglobalload–displacementcurveswaslowerwhereasthepercentageofthestiffness reduction after thefirst loaddrop washigher, compared tothe Glasslaminate. Overall thehybrid results showed some different damage mechanisms, i.e. carbon ply fibre fracture and delamination undertheindenter,withagradualfailurebehaviourandlessdamagetotheinnerlayers.The degradation mechanisms were visually detectable from the indented face from the early stage of the loading for some of the hybrid configurations, which can act as impact damage indicator. <br/>

Topics

• impedance spectroscopy
• Carbon
• tomography
• glass
• glass
• laser emission spectroscopy
• strength
• composite