摘要
目的研究牙科陶瓷材料的力学性能并预测其在循环载荷作用下的寿命。方法采用三点弯曲法对全瓷标准试件进行动疲劳实验。利用特征参数进一步计算材料在循环载荷下作用至断裂的循环次数理论值。结果全瓷材料的三点弯曲强度、特征强度σ0和Weibull模数m分别为425.7、453.8MPa和7.4;亚临界裂纹生长参数n、A和B分别为23.1、3.4×10-15和857.2。全瓷材料的抗折强度预测值10年内下降幅度达47%。数值计算结果显示,牙科陶瓷材料在0～200N循环应力幅值作用下的疲劳寿命理论值为690447次。结论水环境和载荷速率对IPSe.maxPress标准试件的抗折强度值有影响。材料的抗折强度预测值随时间推移逐渐下降。数值计算结果可为体外实验提供校验依据,但需体外循环疲劳及有限元实验对修复体在口内服役的情况进行更精确模拟。
Objectives To investigate the mechanical properties,fatigue parameters and lifetime of IPS e.max Press material via dynamic fatigue experiments,and to obtain the lifetime under cyclic loading from equations.Methods Bar specimens were manufactured with IPS e.max Press material,and inert strength was measured via three-point bending method in silicon oil and analyzed with Weibull statistics.Dynamic fatigue experiments were performed at different stressing rates of 10 MPa/s,1 MPa/s,0.1 MPa/s and 0.05 MPa/s in artificial saliva environment to calculate the subcritical crack growth（SCG） parameters n,A and B.Strength-fracture probability-lifetime（SPT） predictions of the material were derived for a period of 10 years.Based on the SCG parameters,the theoretical number of cycles to fracture（Nf,0） was predicted and the W？觟hler diagram was drawn.Results Inert fracture strength,characteristic strength σ0 and Weibull modulus m were 425.7,453.8 MPa and 7.4 respectively.The SCG parameters n,A and B were determined as 23.1,3.4 × 10-15 and 857.2 respectively.According to the SPT diagram,the characteristic strength of IPS e.max Press was predicted to decrease by 47% after 10 years.A calculated number of cycles to failure was determined as 690 447.Conclusions Humidity and loading rate have an obvious influence on fracture strength of the IPS e.max Press specimens.Predictive fracture strength of the material decreases gradually with the lapse of time.Numerical method can serve as a complementary approach to in vitro experiment.However,cyclic fatigue experiment and finite element modeling are needed for a much more accurate simulation.
出处
《中华口腔医学研究杂志（电子版）》
CAS
2011年第1期22-25,共4页
Chinese Journal of Stomatological Research(Electronic Edition)
基金
国家自然科学基金(30872908)
中山大学重大项目培育和新兴
交叉学科研究项目(10ykjc27)
