空间索网-框架结构精度退化机理与补偿机制研究

The cable-net frame structure is an optimum design scheme for large space deployable structures. In order to assure the working surface on active service in the total lifecycle and further improve the service quality, the accuracy degradation mechanism and compensation methods have become the key problems that need to be solved urgently. Therefore, this project firstly establishes nonlinear mechanical models for the accuracy analysis of the cable-net frame structures with the viscoelastic behaviors, thermal deformation and prestress in consideration. Then, the evolvement rules of some key performance indexes including geometry, prestress and vibration power flow are systematic analyzed to reveal the structural static and dynamic response mechanism. Next, a tensegrity cable-net structure and its design method are proposed to improve the capacity of the cable-net structures to design the large-scale variable curvature reflector. A parameter matching method is investigated for the geometry and material parameters to increase the anti-environment disturbance ability. A tension-compensation spring allocation method is presented to decrease the sensibility of surface accuracy to the thermal and creep deformation. Meanwhile, a vibration suppression method is studied based on the spring’s ability to isolate and absorb vibration wave. Eventually, an experimental system of the cable-net frame structure is manufactured to verify the proposed methods through testing and evaluating its performance.

索网-框架结构是空间大型可展开结构的最佳方案之一，为了保证索网-框架结构全寿命周期的在轨精度保持能力，提高大型可展开结构服役质量，索网-框架结构精度退化机理及补偿机制已成为亟需解决的关键问题。本项目首先研究温度/应力影响下粘弹性索网-框架结构多重非线性耦合力学建模与求解方法，研究结构静态精度与动态精度演变机制。其次，提出新型张-拉网面设计和几何/材料参数匹配设计方法，从结构设计的角度，提高大跨度索网-框架结构服役期内抗环境干扰特性；提出张力补偿弹簧配置方法，解决形面对热应变和蠕变应变敏感的问题，从被动控制的角度，基于波隔离与波吸收原理，研究索网工作形面的振动抑制方法，为索网工作形面的静态与动态精度设计提供新的途径。最后，研制新型索网-框架结构实验系统，通过性能评估，验证所提出的理论与方法。

为了保证索网-框架结构全寿命周期的在轨精度保持能力，提高大型可展开结构服役质量，本项目开展了索网-框架结构精度退化机理及补偿机制研究。首先，完成了温度/应力耦合影响下构件粘弹性本构建模与测试、空间索网-框架结构多重非线性耦合力学建模与求解的研究工作，揭示了空间冷热交替环境下粘弹性构件宏观力学响应规律及结构静态精度演变机制，为空间索网-框架结构高精度设计与补偿奠定了理论基础。其次，完成了索网-框架结构动态精度退化机理、振动功率流传递特性及能量分布的研究工作，提出了谱元波动力学分析法，探索了索网-框架结构索梁耦合振动机理及振动功率流传播路径和能量分布规律。然后，完成了空间索网-框架结构高精度设计与补偿方法研究，提出了新型张-拉网面及其高精度设计方法，实现了在考虑弹性变形时结构的高精度保持，从力学松弛和力热稳定性两个角度，探究了空间索网-框架结构几何/材料参数匹配设计方法，提高了结构的工作精度、热稳定性及使用寿命。最后，建立了单元功率流主动控制方法，实现了空间索网-框架结构宽频域振动控制，在此基础上，完成了实验系统设计与平台搭建，通过实验测试与性能评估，验证了相关理论与方法。