Machine learning(ML)has powerful nonlinear processing and multivariate learning capabilities,so it has been widely utilised in the fatigue field.However,most ML methods are inexplicable black-box models that are diffi...Machine learning(ML)has powerful nonlinear processing and multivariate learning capabilities,so it has been widely utilised in the fatigue field.However,most ML methods are inexplicable black-box models that are difficult to apply in engineering practice.Symbolic regression(SR)is an interpretable machine learning method for determining the optimal fitting equation for datasets.In this study,domain knowledge-guided SR was used to determine a new fatigue crack growth(FCG)rate model.Three terms of the variable subtree ofΔK,R-ratio,andΔK_(th)were obtained by analysing eight traditional semi-empirical FCG rate models.Based on the FCG rate test data from other literature,the SR model was constructed using Al-7055-T7511.It was subsequently extended to other alloys(Ti-10V-2Fe-3Al,Ti-6Al-4V,Cr-Mo-V,LC9cs,Al-6013-T651,and Al-2324-T3)using multiple linear regression.Compared with the three semi-empirical FCG rate models,the SR model yielded higher prediction accuracy.This result demonstrates the potential of domain knowledge-guided SR for building the FCG rate model.展开更多
Stress corrosion cracking (SCC) of a PZT ferroelectric ceramics in various media, such as moist atmosphere, silicon oil, methanol, water and formamide, and its anisotropy have been investigated at constant load test u...Stress corrosion cracking (SCC) of a PZT ferroelectric ceramics in various media, such as moist atmosphere, silicon oil, methanol, water and formamide, and its anisotropy have been investigated at constant load test using a single-edge notched tensile specimen. The results showed that SCC could occur in all media, and the threshold stress intensity factor of SCC in water and formamide, KISCC, revealed anisotropy. The KISCC for poling direction parallel to the crack plane, was greater than that perpendicular to the crack plane, similar to the anisotropy of fracture toughness KIC; however, the anisotropy factor of KISCC, which was =1.8 (in formamide) and 2.1 (in water), was larger than that of KIC, which is =1.4. The stress-induced 90° domain switching causes the anisotropy of KIC and KISCC, besides, the resistance of SCC also has anisotropy.展开更多
Stress corrosion cracking (SCC) of a PZT ferroelectric ceramics in various media, such as moist at-mosphere, silicon oil, methanol, water and formamide, and its anisotropy have been investigated at constant load test ...Stress corrosion cracking (SCC) of a PZT ferroelectric ceramics in various media, such as moist at-mosphere, silicon oil, methanol, water and formamide, and its anisotropy have been investigated at constant load test using a single-edge notched tensile specimen. The results showed that SCC could occur in all media, and the threshold stress intensity factor of SCC in water and formamide, KISCC, revealed anisotropy. The KISCC for poling direction parallel to the crack plane, aISCC,Kwas greater than that perpendicular to the crack plane, bISCC,K similar to the anisotropy of fracture toughness KIC; however, the anisotropy factor of KISCC, which was abISCCISCC/KK=1.8 (in formamide) and 2.1 (in water), was larger than that of KIC, which is abICIC/KK=1.4. The stress-induced 90?domain switching causes the anisotropy of KIC and KISCC, besides, the resistance of SCC also has anisotropy.展开更多
Threshold stress intensity factor of hydrogen-induced cracking (HIC), K IH, of a lead zirconate titanate ferroelectric ceramics (PZT-5) has been measured during dynamic charging with various current densities at const...Threshold stress intensity factor of hydrogen-induced cracking (HIC), K IH, of a lead zirconate titanate ferroelectric ceramics (PZT-5) has been measured during dynamic charging with various current densities at constant load using notched tensile specimens with poling direction parallel or perpendicular to the crack plane. The results show that K IH reveals anisotropy, and the threshold stress intensity factor for the specimen with poling direction parallel to the crack plane, K IH a , is greater than that perpendicular to the crack plane, K IH b , similar to the anisotropy of fracture toughness, K IC. The normalized threshold stress intensity factor of HIC, however, does not reveal anisotropy, and decreass linearly with logarithm of hydrogen concentration, C o, i.e. K IH a /K IC a =K IH b /K IC b =0.4?0.15 In C o. Therefore, the anisotropy of HIC is the same as that of the fracture toughness, and is due to the anisotropy of the stress-induced 90° domain switching.展开更多
基金Supported by Sichuan Provincial Science and Technology Program(Grant No.2022YFH0075)Opening Project of State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure(Grant No.HJGZ2021113)Independent Research Project of State Key Laboratory of Traction Power(Grant No.2022TPL_T03).
文摘Machine learning(ML)has powerful nonlinear processing and multivariate learning capabilities,so it has been widely utilised in the fatigue field.However,most ML methods are inexplicable black-box models that are difficult to apply in engineering practice.Symbolic regression(SR)is an interpretable machine learning method for determining the optimal fitting equation for datasets.In this study,domain knowledge-guided SR was used to determine a new fatigue crack growth(FCG)rate model.Three terms of the variable subtree ofΔK,R-ratio,andΔK_(th)were obtained by analysing eight traditional semi-empirical FCG rate models.Based on the FCG rate test data from other literature,the SR model was constructed using Al-7055-T7511.It was subsequently extended to other alloys(Ti-10V-2Fe-3Al,Ti-6Al-4V,Cr-Mo-V,LC9cs,Al-6013-T651,and Al-2324-T3)using multiple linear regression.Compared with the three semi-empirical FCG rate models,the SR model yielded higher prediction accuracy.This result demonstrates the potential of domain knowledge-guided SR for building the FCG rate model.
文摘Stress corrosion cracking (SCC) of a PZT ferroelectric ceramics in various media, such as moist atmosphere, silicon oil, methanol, water and formamide, and its anisotropy have been investigated at constant load test using a single-edge notched tensile specimen. The results showed that SCC could occur in all media, and the threshold stress intensity factor of SCC in water and formamide, KISCC, revealed anisotropy. The KISCC for poling direction parallel to the crack plane, was greater than that perpendicular to the crack plane, similar to the anisotropy of fracture toughness KIC; however, the anisotropy factor of KISCC, which was =1.8 (in formamide) and 2.1 (in water), was larger than that of KIC, which is =1.4. The stress-induced 90° domain switching causes the anisotropy of KIC and KISCC, besides, the resistance of SCC also has anisotropy.
文摘Stress corrosion cracking (SCC) of a PZT ferroelectric ceramics in various media, such as moist at-mosphere, silicon oil, methanol, water and formamide, and its anisotropy have been investigated at constant load test using a single-edge notched tensile specimen. The results showed that SCC could occur in all media, and the threshold stress intensity factor of SCC in water and formamide, KISCC, revealed anisotropy. The KISCC for poling direction parallel to the crack plane, aISCC,Kwas greater than that perpendicular to the crack plane, bISCC,K similar to the anisotropy of fracture toughness KIC; however, the anisotropy factor of KISCC, which was abISCCISCC/KK=1.8 (in formamide) and 2.1 (in water), was larger than that of KIC, which is abICIC/KK=1.4. The stress-induced 90?domain switching causes the anisotropy of KIC and KISCC, besides, the resistance of SCC also has anisotropy.
基金This work was supported by the Special Funds for the Major State Basic Research (G 19990650) and the National Natural Science Foundation of China (Grant No. 50131160738).
文摘Threshold stress intensity factor of hydrogen-induced cracking (HIC), K IH, of a lead zirconate titanate ferroelectric ceramics (PZT-5) has been measured during dynamic charging with various current densities at constant load using notched tensile specimens with poling direction parallel or perpendicular to the crack plane. The results show that K IH reveals anisotropy, and the threshold stress intensity factor for the specimen with poling direction parallel to the crack plane, K IH a , is greater than that perpendicular to the crack plane, K IH b , similar to the anisotropy of fracture toughness, K IC. The normalized threshold stress intensity factor of HIC, however, does not reveal anisotropy, and decreass linearly with logarithm of hydrogen concentration, C o, i.e. K IH a /K IC a =K IH b /K IC b =0.4?0.15 In C o. Therefore, the anisotropy of HIC is the same as that of the fracture toughness, and is due to the anisotropy of the stress-induced 90° domain switching.
