Asaoka K, Kuwayama N
Shika Rikogaku Zasshi. 1980 Apr;21(54):103-8.
Metal-ceramic composite materials as a porcelain fused to metal restoration, have been used for biomaterials. But the chief objection, to use of these materials as restorative materials, is its lack of strength, particularly tensile and shear strength. And the materials to have strong bond strength have been studied. On the other hand, the bond strength along metal-ceramic interface have usually measured by a pull out test. At the same time, the objection of the pull out test are pointed out. So, the deformation of metal-ceramic composite materials by the pull out test were simulated to use the axi-symmetric finite element method. And shear stress distribution along the interface and the principal stress distribution in ceramic were calculated. The following results were obtained. (1) Shear stress along the interface and maximum principal stresses in ceramic and in metal decrease rapidly along the interface. (2) The stress concentration factor as the case of the alloy with high Young's modulus is smaller than that of the alloy with low Young's modulus. So, the former would be stronger about the pull out test. (3) Metal-ceramic interface length is not affected for shear stress concentration. If the specimen has more than the critical interface length, the initial crack in ceramic would be occurred at the same pull out force.
金属陶瓷复合材料作为一种烤瓷熔附金属修复体，已被用作生物材料。但将这些材料用作修复材料的主要问题是其强度不足，尤其是拉伸强度和剪切强度。人们一直在研究具有强粘结强度的材料。另一方面，金属陶瓷界面的粘结强度通常通过拔出试验来测量。同时，也指出了拔出试验存在的问题。因此，采用轴对称有限元方法模拟了拔出试验中金属陶瓷复合材料的变形情况，并计算了沿界面的剪应力分布和陶瓷中的主应力分布。得到了以下结果。(1) 沿界面的剪应力以及陶瓷和金属中的最大主应力沿界面迅速减小。(2) 杨氏模量高的合金情况下的应力集中系数小于杨氏模量低的合金。因此，前者在拔出试验中会更强。(3) 金属陶瓷界面长度对剪应力集中没有影响。如果试样的界面长度超过临界界面长度，陶瓷中的初始裂纹将在相同的拔出力下出现。
