Compression after impact & vibrational analysis of aramid-basalt/epoxy interply composites under hygrothermal conditions

With the application of composites in various industries viz. aerospace, automobile, defence and marine, it becomes essential to carry out the Compression After Impact (CAI) and vibration tests to study their behavior in different environmental conditions. This study investigates the significance of CAI and damping characteristics of the aramid-basalt/epoxy interply composites under different hygrothermal conditions. In this examination, laminates were exposed to three different ageing conditions, namely, ambient (ageing in distilled water at 25°C), sub-zero (ageing in distilled water at −10°C), and humid (ageing in an environmental chamber maintained at 40°C and 60% relative humidity) for a duration of 180 days. Moisture saturated specimens were subjected to low velocity impacts (LVI) of 10 J and 15 J energy levels using drop weight impact method. CAI test was carried out on post impact specimens to analyze the residual compressive strengths. Furthermore, impact hammer and impedance tube tests were also conducted to compute the damping properties and sound transmission loss (dB) of the specimens. The results were compared with the pristine samples to analyze the effect of hygrothermal conditions on the CAI and vibrational properties. The results indicated that the moisture has a detrimental effect on the compressive residual strength, natural frequency, and sound transmission loss of the specimens. The Scanning Electron Microscopy (SEM) of fractured CAI specimens displayed the occurrence of various types of damages such as fiber fractures, delamination, matrix fractures, etc as the primary reason for failure of the specimens.