基于三维重构的泡沫混凝土静动态性能研究

Foam concrete has superior performance due to being lightweight, thermal isolative, sound absorptive and vibration reducing. Its designable parameters and easy replacement after damage make it a promising material. However, foam concrete application in structural and protective engineering is limited to some extent due to lacking of thorough understanding of its static and dynamic performance. In this project, CT scanning is applied to generate high accuracy geometry model, and 3D printing is employed to fabricate foam gypsum and epoxy specimens with the geometry model. A series of deliberately designed tests will be conducted to decouple the key factors governing the compressive strength, from which a more realistic compressive strength model of foam concrete will be established. Split Hopkinson pressure bar, high speed direct compression, Taylor bar and shock tube tests will be conducted to investigate the dynamic response, energy absorption, and load transfer of foam concrete subjected to dynamic loads with a wide spectrum of strain rate. Furthermore, the effect of gradient on dynamic performance of foam concrete will be examined, which leads to optimized design in protective engineering. The outcomes of this project will deepen the understanding of static and dynamic performance of foam concrete, and pave the way for its applications in protective engineering, which has important significance in terms of both scientific merit and engineering application.

泡沫混凝土具有轻质、隔热、吸声、减震等优异性能。其各项参数可设计，损坏后可快速替换等优点，具有广泛的应用前景。由于对其静动态性能研究不够透彻，泡沫混凝土在结构防护领域的应用受到一定限制。本项目基于三维重构，应用CT扫描对泡沫混凝土进行精细化建模，3D打印一系列具有相同三维重构几何特征的泡沫石膏和泡沫树脂，设计试验对决定其压缩强度的因素进行解耦分析，建立更加符合实际的泡沫混凝土压缩强度模型。在此基础上开展霍普金森压杆、高速直接压缩、泰勒杆和激波管试验，配合数字图像相关技术对泡沫混凝土在不同应变率下的动态响应、能量吸收和载荷传递进行研究。进一步研究梯度对泡沫混凝土动态性能的影响并进行针对防护工程应用的优化设计。研究成果将加深对泡沫混凝土静动态性能的理解，为其在防护工程领域的应用奠定坚实基础，具有重要科学意义与工程实用价值。

泡沫混凝土因具有密度低、造价低、吸能优异的特点，在结构防护领域，内含泡沫混凝吸能层的牺牲挂板具有广阔的应用前景。为了更深入地研究泡沫混凝土的静动态力学性能及吸能性能，本项目采用试验研究，数值计算和理论分析等手段，得到了以下研究结论：（1）泡沫混凝土密度增加会提高峰值应力，但会减小压实应变，因此比吸能会先升高后降低；（2）应变率效应随着泡沫混凝土的密度升高而越发显著；（3）玄武岩纤维能有效提高泡沫混凝土的抗拉强度及极限拉应变，但对抗压强度和吸能能力作用不明显。（4）CT扫描泡沫混凝土内部孔隙结构发现内部孔隙形状接近于球形，且孔隙直径基本呈现正态分布。（5）基于泡沫混凝土内部孔隙分布，所建立的细观模型能有有效预测其力学行为。（6）提出的梯度泡沫混凝土材料形式通过逐级变形，分级吸能的方式实现结构结构防护的目的。上述研究成果将加深对泡沫混凝土静动态性能的理解，为其在防护工程领域的广泛应用，具有重要科学意义与工程实用价值。