TY - JOUR T1 - Study of Residual Tensile Strength in Drilled Composite Laminates by Acoustic Emission TT - پایش استحکام کاهش یافته قطعات کامپوزیتی سوراخ شده توسط روش آکوستیک امیشن JF - mdrsjrns JO - mdrsjrns VL - 13 IS - 15 UR - http://mme.modares.ac.ir/article-15-6011-en.html Y1 - 2014 SP - 169 EP - 183 KW - Drilling KW - Composite Materials KW - residual strength KW - Acoustic emission KW - Wavelet Analysis N2 - Drilling of composite materials is one of the major processes in the manufacturing and assembly of sub-component. However, drilling of composite laminates can cause several damages such as degradation in residual tensile strength. In this study, effects of cutting speed, feed rate and drill angle on residual tensile strength of drilled laminates has been investigated. For this purpose, the Taguchi method was employed for three factors at three levels. Acoustic emission signals and wavelet analysis are used to monitor residual tensile strength. The experimental results indicated that the feed rate has the most significant effect. Based on time-frequency analysis of AE signals, it was found that AE signals with frequency ranges of (62.5-125), (250-312.5) and (312.5-375) KHz were generated from matrix cracking, fiber slipping and fiber breakage respectively. M3 ER -