研究了液晶高弹体材料在力-热-光耦合作用下的力学行为，获得了三维本构关系与力-序-指向矢相互作用的热力学平衡条件，建立了梁、板等典型结构光致弯曲的控制方程，通过近似解析求解、级数解和数值模拟计算了其弯曲行为，分析了其弯曲机理、变化规律及影响因素。结果表明光照会使结构沿光照方向产生梯度变化的应变和弹性模量，应变的梯度变化使结构弯曲，模量的梯度变化加剧了弯曲的非线性行为。弯曲的结构中应力分布与经典弯曲的线性分布相差很大，并与光强、结构参数和材料常数密切相关。热与光的作用相互耦合，不同温度下光照的影响不同，而光致异构化又会产生热。对力-序-指向矢耦合作用的分析表明，与温度和光一样，力也会改变序参量，诱发液晶相变，还会导致指向矢的旋转，引起微结构（液晶畴）的变化。这与我们对形状记忆合金应力诱发马氏体相变过程微结构演化的实验观察有许多相似之处。还分析了多层结构的热力学行为，对其弯曲行为和应力分布与材料和几何常数的关系建立了解析模型，找出了影响规律。.本项目已初步弄清了该类材料在多场耦合下的力学行为，建立了合理的本构模型和典型结构的控制方程，获得了解析与数值求解的工具，这为其工程应用打下了基础。

The mechnical-thermal-optical coupling effect is studied. Three dimensional constitutive equations and the mechanical-order-director coupling euqations are obtained through thermodynamical analysis. The control equations for the light induced bending of beams and plates are obtained. Analytical and series solutions as well as numerical simulations are utilized to analyze the mechanism of optical bending. The results show that upon light illumination, the materials will contract gradually along the propagation direction of light and at the same time, the elastic modulus will be changed. The gradually changing contraction resulted in the bending and varying modulus make the bending even more nonlinear. Very different from the linear distribution in normal bending, the stress distribution is highly nonlinear in optical bending. It was found that the thermal-optical coupling is particularly strong, optical bending is affected by the temperature and photoisomerization process will produce heat as well. Mechanical force can change the order parameter and rotate the director, thus induce nematic-isotropic phase transitions and change the microstructures (domains) of liquid crystal elastomers. This has many similarities as the microstructure evolution we have observed experimentally in stress induced martensitic transformations in shape memory alloys. Multilayered structures are analyzed as well due to its potential applications for optical controled devices. The bending and stress distributions are studied through analytical models. The effect of the material and geometrical parameters on the mechanical behavior are analyzed..The above study has clarified the multi-fields coupling behavior of liquid crystal elastomers. The three dimensional contitutive relations and the control equations for the optical bending of beams and plates are proposed. The calculation tools are obtained. The works should also be very useful for the applications of such materials.

研究了液晶高弹体材料在力-热-光耦合作用下的力学行为，获得了三维本构关系与力-序-指向矢相互作用的热力学平衡条件，建立了梁、板等典型结构光致弯曲的控制方程，通过近似解析求解、级数解和数值模拟计算了其弯曲行为，分析了其弯曲机理、变化规律及影响因素。结果表明光照会使结构沿光照方向产生梯度变化的应变和弹性模量，应变的梯度变化使结构弯曲，模量的梯度变化加剧了弯曲的非线性行为。弯曲的结构中应力分布与经典弯曲的线性分布相差很大，并与光强、结构参数和材料常数密切相关。热与光的作用相互耦合，不同温度下光照的影响不同，而光致异构化又会产生热。对力-序-指向矢耦合作用的分析表明，与温度和光一样，力也会改变序参量，诱发液晶相变，还会导致指向矢的旋转，引起微结构（液晶畴）的变化。这与我们对形状记忆合金应力诱发马氏体相变过程微结构演化的实验观察有许多相似之处。还分析了多层结构的热力学行为，对其弯曲行为和应力分布与材料和几何常数的关系建立了解析模型，找出了影响规律。本项目已初步弄清了该类材料在多场耦合下的力学行为，建立了合理的本构模型和典型结构的控制方程，获得了解析与数值求解的工具，这为其工程应用打下了基础。