人造结石的静动态巴西劈裂试验研究

Study on Static and Dynamic Brazilian Splitting Test of Artificial Stones

为探讨人造结石在不同条件下的力学性能,制备了不同配比(硬度、孔隙率、粉水比、蛋白含量)的牙科石膏试样(人造结石),对其开展准静态巴西劈裂试验,并利用φ40 mm分离式霍普金森压杆进行动态加载,结合高速相机、数字图像相关等测试方法观察试样在劈裂过程中的破坏过程以及应变场演化规律,获得应变时程曲线。试验结果表明:人造结石的准静态拉伸强度与硬度、粉水比成正比,与孔隙率成反比,而蛋白质含量对拉伸强度的影响不大,但会影响其韧脆性。在动态加载下,人造结石试样具有明显的应变率强化效应,拉伸强度动态增强因子与应变率对数之间呈线性增长关系。研究方法为人造结石的力学特性研究提供了一种有效的实验方法和分析手段。

This article aims to explore the mechanical properties of artificial stones under different conditions.Firstly,dental plaster samples with different ratios(hardness,porosity,powder-to-water ratio,and protein content)were prepared as artificial stones to study the splitting behavior.Secondly,quasi-static Brazilian splitting test were conducted on artificial stones.Finally,aφ40 mm split Hopkinson pressure bar(SHPB)was used for dynamic loading,combined with high-speed cameras,digital image correlation(DIC)and other testing methods to observe the damage process during sample splitting and the evolution law of the strain field,and then obtain the strain time history curve of the sample was obtained.Test results show that the quasi-static tensile strength of artificial stones is directly proportional to the hardness and powder-towater ratio,and inversely proportional to the porosity.And the protein content has little effect on the tensile strength of the material,but it does affect its ductility and brittleness.Under dynamic loading,the artificial stone specimen has an obvious strain rate strengthening effect.There is a linearly increasing relationship between the dynamic enhancement factor for tensile strength and the logarithm of the strain rate.This article provides an effective test method and analysis technique for studying the mechanical properties of artificial stones.