具有双压缩应力平台硅橡胶泡沫材料的构筑及压缩特性研究

The damping protection of weapons system plays an important role in assuring the stability of weapons system in process of flight and the availability of strategic damage.In the pretightening contanted damping structure, the silicone rubber foams don’t obviously exhibit a good platform of compressive stress，which leads to the range of mechanical self-adaption restricted. Despite the fact that the platform of hierarchical structure in silicone rubber foams is of great importance to prevent invalidating weapons system because of the stress overload, the special structure hasn’t been obtained by the existing methods. In this project, designed as a special structure, the silicone rubber matrix is composed of the micropore and the layered orientation of the alternating multilayered structure. The problem that the silicone rubber foams don’t have the obvious platform of compressive stress because of the small Young’s modulus of elasticity will be solved by means of microcellular structure. When external force parallels to the layered orientation of the alternating multilayered structure, the compressive property of foam materials will appear in the non foaming structure. The silicone rubber foams with the double platform of compressive stress will be achieved with the acid of the above characteristic. The novel the compressive platform structure will avoid the failure of damping protection resulting from the stress overload. Meanwhile, not only will the effect of the microstructure on the compressive property be discovered, but also the evolving mechanics in the process of compression will be structured. To provide a theory for the design of damping materials in weapons system, the characterization of the macroscopic property and the finite element computation will applied. Hence, the work will show an important theoretical meaning and value in engineering use.

武器系统的减振防护对确保其飞行过程的稳定性和战略毁伤的有效性具有重要的作用。在预紧接触式减振结构中所使用的硅橡胶泡沫材料存在压缩应力平台不明显导致力学自适应范围受限，以及现有方法难以构筑分级结构的压缩应力平台来防止应力过载导致武器系统失效的问题。本项目拟在硅橡胶基体中设计一种微孔和交替多层的层状取向并存的结构，利用微孔结构来改善泡壁抗弯强度，以克服基体因杨氏弹性模量小导致压缩平台不明显的问题，并利用交替多层的层状取向结构在外力平行于层状界面时可呈现出类似泡沫材料的压缩特性，来实现具有双压缩应力平台硅橡胶泡沫材料的构筑。这种全新的压缩应力平台结构可避免系统因应力过载（第二个平台）导致减振防护失效的弊端。同时，结合宏观性能表征和有限元等计算模拟，揭示这种微观结构影响压缩性能的规律和建立压缩过程中的演变机制模型，为武器系统用减振材料的设计和构筑提供理论依据，具有重要的理论意义和工程应用价值。

本项目主要致力于通过硅橡胶泡孔结构的调控来实现具有双压缩应力平台硅橡胶泡沫材料的构筑。主要研究内容和结果如下：.1.针对硅橡胶交联度与scCO2的吸附和解吸附匹配关系研究，发现scCO2在硅橡胶基体中扩散行为属于动态平衡过程，scCO2在硅橡胶基体中的扩散系数大约在10-7m2/s，其比在热塑性基体中的扩散系数高3到4个数量级。.2.针对scCO2对硅橡胶硫化性能的影响研究，发现有机硅橡胶经过scCO2饱和前后的硫化过程均表现出自催化反应的特征。且scCO2溶解于硅橡胶基体中，溶解量随饱和条件的变化而改变，且Ea随着饱和条件越苛刻而逐渐减小。.3.针对硅橡胶泡沫材料泡孔结构设计与调控研究，发现POSS粒子对硅橡胶硫化具有阻碍作用。POSS粒子的引入起到了异相成核作用，其能够进一步降低成核能垒，进而导致泡孔孔径的降低和泡孔密度的增加。在scCO2制备微孔硅橡胶泡沫过程中发现，泡孔的生长过程有别于热塑性泡沫材料，即泡孔结构是在回缩过程中完成定型。.4.针对多级剪切或拉伸过程对交替多层硅橡胶形态的影响研究，发现利用白炭黑补强体系对硅橡胶泡沫材料泡孔结构的影响，成功构筑了基于交替多层泡孔结构的微孔硅橡胶泡沫材料，并发现沉淀法白炭黑补强的硅橡胶基体材料具有更高的基体强度，使得泡孔回缩能力更强，导致其泡孔尺寸减小。利用调控硅橡胶基体弹塑性通过对两种硅橡胶基体弹塑性调控，实现了泡沫/实体交替层状硅橡胶泡沫材料的构筑。.5.针对泡孔结构对硅橡胶泡沫材料压缩性能的影响研究，发现硅橡胶泡孔结构的微小化能够提升硅橡胶泡沫的压缩性能。利用有限元模拟计算发现，泡孔结构的微孔化能够给泡壁提供更高的反向支持力，从而可提高其压缩性能。交替多层微孔硅橡胶泡沫材料在压缩过程中能够产生两个压缩平台区。其第一个平台来至于弱硅橡胶基体泡孔结构在受力状态因泡孔塌陷而产生，而第二平台来至于强硅橡胶基体泡孔结构在受力状态因泡孔塌陷而产生。