碳纤维波纹管弯曲刚度的测量及有限元分析

Measurements and finite element analyses of the bending stiffness of laminated carbon fiber bellows

飞轮存储动能正比于其转动惯量和角速度平方,使用碳纤维复合材料可有效提高转子线速度,而通过波纹管连接圆筒的多节式飞轮转子设计,不仅便于增大转动惯量,而且考虑到波纹管弯曲刚度对转子固有频率的影响,可实现在较低转速下过临界,增大工作转速范围。该文针对渐变铺层的碳纤维波纹管,通过轴向施力法测量其静态弯曲刚度,建立对应的有限元模型,计算不同载荷下线性和考虑几何非线性的弯曲刚度,并模拟不同下铺层的弯曲刚度。研究结果表明:波纹管弯曲刚度与载荷是非线性关系,载荷较大时测量值与理论值数量级一致,弯曲刚度随铺层数增多、轴向铺层比增加而增大,且受铺层次序影响。

The kinetic energy stored in a flywheel depends on its rotational inertia and linear velocity.The use of carbon fiber composite materials can effectively improve the rotor speed and increasing the rotor length can increase its rotational inertia.Furthermore,multi-section flywheel rotors formed by connecting tubes through bellows enables the rotor to pass through critical frequencies at low speeds,which increases the working speed range.This paper studies the bending stiffnesses of variable thickness carbon fiber bellows with the static bending stiffness measured by the axial force method.A finite element model was then used to predict the linear and geometric nonlinear bending stiffness for various loads and various laminates.The research indicates that bending stiffness variation is nonlinear with the load,with the measured stiffness being of the same order of magnitude as the theoretical values for large load.The simulations also show how the thickness,angle and stacking sequence of the laminate affect the bending stiffness.