Influence of various damage mechanisms on the low‐velocity impact response of composite laminates

Abstract This study exhibits the effect of different damage mechanisms on the mechanical behavior of composite laminates subjected to low‐velocity impact load. To achieve this, seven low‐velocity impact energies were applied to laminates with five different thicknesses and four unique stacking sequences. The extent of damage was quantitatively evaluated through contact measurements and ultrasonic C‐scan techniques. Numerical simulations, showing good agreement with experimental results, characterized the distribution and evolution of damage within the laminates. The findings reveal that when matrix and delamination damage are predominant, the dent depth increases slowly and is visually invisible, while the delamination area expands almost linearly. Conversely, When fiber damage prevails, the laminate absorbs more energy, leading to rapid increases in dent depth, the appearance of visible cracks, and the occurrence of sharp fluctuations with multiple peaks in contact force and displacement curves. Nonetheless, the delamination area and projection tend to be stable and unchanged. Furthermore, alterations in thickness and stacking sequence directly affect the damage characteristics and energy absorption properties. This research offers valuable theoretical insights and serves as a reference for enhancing the comprehension of the failure mechanism of laminates and optimizing their performance. Highlights Demonstrate the utility of dent depth in identifying changes in damage mechanisms. Evaluate the delamination damage of laminates after impacts by ultrasonic C‐scan techniques. Reveal the regulation of impact response parameters for different damage mechanisms. Investigate the effect of variation in thickness on damage characteristics and energy absorption. Evaluate the impact resistance of laminates with different stacking sequences.