Damage characteristics of TC4 flyer obliquely penetrating CF/BMI laminates under high temperature environment

Abstract

In response to the urgent need for high-temperature-resistant, impact-resistant resin-based composites for the fan containment case of high thrust-to-weight ratio turbofan engines, numerical simulations were conducted for the oblique penetration of Ti- 6 Al- 4 V (TC4) flyers into CF/BMI laminates at different temperatures (200 °C and 300 °C) and variable yaw and pitch angles (0°, 10°, 20°, 30°, and 40°). A mesoscale model was established, considering the material laminate structure and surface weaving structure. The accuracy of the numerical simulation method was validated through experiments. The impact of different incident angles on the failure modes and energy absorption characteristics of the composite laminates at high temperatures were analyzed. The results indicate that, in terms of failure modes, under oblique penetration conditions, the failure modes of the laminate primarily include laminate cracking, shear plugging, fiber tensile fracture, and resin cracking. When the yaw angle is larger, local stresses cause cracking on the back of the target, mainly due to local shear plugging. When the pitch angle is larger, the laminate bending deformation is concentrated locally, and the overall deformation of the laminate is minimal. Shear and tensile failure occur between the fibers and resin matrix, causing the flyer to detach. The fibers on the upper side of the flyer experience deflection. As the temperature increases, the performance of the matrix is observed to decline, leading to thermal stress mismatch between the fibers and the matrix. Plastic deformation of the matrix occurs, resulting in a weakening of the interfacial bonding strength between the fibers and the matrix. Fiber bundles are found to fracture, and the phenomenon of interfacial debonding becomes more pronounced. In terms of energy absorption characteristics, as the yaw angle increases, the flyer is observed to consume more kinetic energy, and the strain energy and frictional dissipation energy of the laminate also increase. Under large-angle oblique penetration conditions, the laminate exhibits stronger impact resistance. As the pitch angle increases, the laminate kinetic energy absorption time is extended, frictional dissipation energy increases, the time for the flyer to penetrate the target is prolonged, and the remaining kinetic energy decreases. An increase in temperature leads to a reduction in the impact resistance of the laminate.