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为提高飞行器的适坠性能,对二维三轴编织复合材料机身隔框的冲击动力学特性进行研究。基于连续介质损伤力学建立了机身隔框在冲击载荷作用下的有限元模型。该模型根据不可逆热力学理论并结合Weibull分布建立损伤扩张准则,采用Hashin失效准则确定损伤阈值函数。在迭代过程中,剪应力与正应力相互耦合,且分别考虑材料在纵向和横向的损伤破坏。在此基础上研究了材料参数变化对机身隔框冲击动力学性能的影响,并对各种情况下的瞬态动力学特征和能量吸收特性进行对比分析。数值结果表明该有限元模型能够准确求解编织复合材料机身隔框的非线性瞬态动力学问题,载荷峰值和吸收的能量分别与试验结果相差1.5%和4.7%,且纵向的弹性模量和压缩强度等材料参数对机身隔框的冲击动力学响应影响较大。
In order to improve the fitness of the aircraft, the impact dynamics of two-dimensional three-axis braided composite fuselage frame was studied. Based on the continuum damage mechanics, the finite element model of the fuselage frame under impact load is established. According to the theory of irreversible thermodynamics and Weibull distribution, this model establishes the damage expansion criterion, and uses the Hashin failure criterion to determine the damage threshold function. During the iteration, shear stress and normal stress are coupled with each other, and the damage damage of the material in the longitudinal and transverse directions are considered separately. On this basis, the impact of material parameters on the impact dynamic properties of the fuselage frame was studied, and the transient dynamic characteristics and energy absorption characteristics under different conditions were compared and analyzed. The numerical results show that the finite element model can accurately solve the nonlinear transient dynamics of the bulkhead of woven composite materials. The peak load and absorbed energy differ by 1.5% and 4.7% respectively from the experimental results. The longitudinal modulus of elasticity and Compressive strength and other material parameters on the impact of the bulkhead impact dynamics greater impact.