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In an attempt to increase resource efficiency and reduce carbon emissions, the development of lightweight designs in structural applications is essential. In addition, the lightweight structures often follow complex topologically optimized designs which are more suitable for the application of additive, in contrast to conventional manufacturing techniques. Within the additive manufacturing (AM) process, constituents may be combined to design and produce durable and lightweight materials with predefined mechanical, electrical, and thermal properties, while also accounting for their sustainability and recyclability. Regretfully, due to the lack of research in material behavior, the AM technology implementation in engineering applications is still limited in comparison to traditional manufacturing methods. While the potential of additively manufactured continuous fiber composites has already been recognized in the scientific community, constitutive modeling and damage resistance are seldom reported. Since fiber-reinforced composite structures are rarely designed as unidirectional (UD), this study is focused on numerical analysis of failure for multi-directionally reinforced composite laminates loaded in a uniaxial direction. Specimens are modeled and evaluated using a progressive damage model, proposing guidelines for safer design and application.

A coupled model of aeroservoelasticity and hydraulic actuator used for failure simulation is presented. The mathematical model composites rigid-body modes, elastic modes, control surface modes, unsteady aerodynamic forces and failure models (jam, loss of control (LOC), oscillatory failure, and hydraulic fluid leakage). A clear framework of coupling method of airplane aeroelastic equation and control surface dynamic equation is provided to study the impacts of surface failures on rigid-elastic motion of airplane. The coupled model is shown to be effective in evaluation of gust response in both discrete gust and continuous turbulence conditions compared with results obtained from the 3-order simplified actuator. Examples of gust load alleviation (GLA) system with LOC of ailerons are given. Results show that total loss of function of GLA system is caused by the LOC. With continuous turbulence excitation, the failure loads is several times larger than that without GLA system.