Haijie Wang, Xintian Liu, Que Wu, Xiaolan Wang and Yansong Wang
The purpose of this paper is to obtain a more accurate fatigue life of structures by introducing the surface roughness into fatigue life prediction model.
Abstract
Purpose
The purpose of this paper is to obtain a more accurate fatigue life of structures by introducing the surface roughness into fatigue life prediction model.
Design/methodology/approach
Based on the fatigue life prediction model with surface roughness correction, the shock absorber cylinder is taken as an example to verify the feasibility of the improved method. Based on the load of the shock absorber cylinder during driving, fatigue experiments are performed under longitudinal and lateral forces, respectively. Then, the fatigue life predicted by the modified model is compared with that predicted by the traditional model.
Findings
By comparing with the test results, considering the influence of mean stress, the Manson method is more accurate in life prediction. Then, the modified Manson-Coffin and Manson method with surface roughness is more accurate in life prediction under longitudinal force and lateral forces, respectively. This verifies the feasibility of the improved method with the surface roughness.
Originality/value
The research on the influence of surface roughness on fatigue life can lay the technical foundation for the life prediction of products and have great significance to the quality evaluation of products.
Details
Keywords
Haiyan Ge, Xintian Liu, Yu Fang, Haijie Wang, Xu Wang and Minghui Zhang
The purpose of this paper is to introduce error ellipse into the bootstrap method to improve the reliability of small samples and the credibility of the S-N curve.
Abstract
Purpose
The purpose of this paper is to introduce error ellipse into the bootstrap method to improve the reliability of small samples and the credibility of the S-N curve.
Design/methodology/approach
Based on the bootstrap method and the reliability of the original samples, two error ellipse models are proposed. The error ellipse model reasonably predicts that the discrete law of expanded virtual samples obeys two-dimensional normal distribution.
Findings
By comparing parameters obtained by the bootstrap method, improved bootstrap method (normal distribution) and error ellipse methods, it is found that the error ellipse method achieves the expansion of sampling range and shortens the confidence interval, which improves the accuracy of the estimation of parameters with small samples. Through case analysis, it is proved that the tangent error ellipse method is feasible, and the series of S-N curves is reasonable by the tangent error ellipse method.
Originality/value
The error ellipse methods can lay a technical foundation for life prediction of products and have a progressive significance for the quality evaluation of products.
Details
Keywords
Haijie Wang, Jianrui Zhang, Bo Li and Fuzhen Xuan
By incorporating the defect feature information, an ML-based linkage between defects and fatigue life unaffected by the time scale is developed, the primary focus is to…
Abstract
Purpose
By incorporating the defect feature information, an ML-based linkage between defects and fatigue life unaffected by the time scale is developed, the primary focus is to quantitatively assess and elucidate the impact of different defect features on fatigue life.
Design/methodology/approach
A machine learning (ML) framework is proposed to predict the fatigue life of LPBF-built Hastelloy X utilizing microstructural defects identified through nondestructive detection prior to fatigue testing. The proposed method combines nondestructive micro-computerized tomography (micro-CT) technique to comprehensively analyze the size, location, morphology and distribution of the defects.
Findings
In the test set, SVM-based fatigue life prediction exhibits the highest accuracy. Regarding the defect information, the defect size significantly affects fatigue life, and the diameter of the circumscribed sphere of the largest defect has a critical effect on fatigue life.
Originality/value
This comprehensive approach provides valuable insights into the fatigue mechanism of structural materials in defective states, offering a novel perspective for better understanding the influence of defects on fatigue performance.
Details
Keywords
Xintian Liu, Jiazhi Liu, Haijie Wang and Xiaobing Yang
To improve the accuracy of parameter prediction for small-sample data, considering the existence of error in samples, the error circle is introduced to analyze original samples.
Abstract
Purpose
To improve the accuracy of parameter prediction for small-sample data, considering the existence of error in samples, the error circle is introduced to analyze original samples.
Design/methodology/approach
The influence of surface roughness on fatigue life is discussed. The error circle can treat the original samples and extend the single sample, which reduces the influence of the sample error.
Findings
The S-N curve obtained by the error circle method is more reliable; the S-N curve of the Bootstrap method is more reliable than that of the Maximum Likelihood Estimation (MLE) method.
Originality/value
The parameter distribution and characteristics are statistically obtained based on the surface roughness, surface roughness factor and intercept constant. The original sample is studied by an error circle and discussed using the Bootstrap and MLE methods to obtain corresponding S-N curves. It provides a more trustworthy basis for predicting the useful life of products.
Details
Keywords
Jun Huang, Haijie Mo and Tianshu Zhang
This paper takes the Shanghai-Shenzhen-Hong Kong Stock Connect as a quasi-natural experiment and investigates the impact of capital market liberalization on the corporate debt…
Abstract
Purpose
This paper takes the Shanghai-Shenzhen-Hong Kong Stock Connect as a quasi-natural experiment and investigates the impact of capital market liberalization on the corporate debt maturity structure. It also aims to provide some policy implications for corporate debt financing and further liberalization of the capital market in China.
Design/methodology/approach
Employing the exogenous event of Shanghai-Shenzhen-Hong Kong Stock Connect and using the data of Chinese A-share firms from 2010 to 2020, this study constructs a difference-in-differences model to examine the relationship between capital market liberalization and corporate debt maturity structure. To validate the results, this study performed several robustness tests, including the parallel test, the placebo test, the Heckman two-stage regression and the propensity score matching.
Findings
This paper finds that capital market liberalization has significantly increased the proportion of long-term debt of target firms. Further analyses suggest that the impact of capital market liberalization on the debt maturity structure is more pronounced for firms with lower management ownership and non-Big 4 audit. Channel tests show that capital market liberalization improves firms’ information environment and curbs self-interested management behavior.
Originality/value
This research provides empirical evidence for the consequences of capital market liberalization and enriches the literature on the determinants of corporate debt maturity structure. Further this study makes a reference for regulators and financial institutions to improve corporate financing through the governance role of capital market liberalization.
Details
Keywords
Haijie Yu, Haijun Wei, Daping Zhou, Jingming Li and Hong Liu
This study aims to reconstruct the frictional vibration signal from noise and characterize the running-in process by frictional vibration.
Abstract
Purpose
This study aims to reconstruct the frictional vibration signal from noise and characterize the running-in process by frictional vibration.
Design/methodology/approach
There is a strong correlation between tangential frictional vibration and normal frictional vibration. On this basis, a new frictional vibration reconstruction method combining cross-correlation analysis with ensemble empirical mode decomposition (EEMD) was proposed. Moreover, the concept of information entropy of friction vibration is introduced to characterize the running-in process.
Findings
Compared with the wavelet packet method, the tangential friction vibration and the normal friction vibration reconstructed by the method presented in this paper have a stronger correlation. More importantly, during the running-in process, the information entropy of friction vibration gradually decreases until the equilibrium point is reached, which is the same as the changing trend of friction coefficient, indicating that the information entropy of friction vibration can be used to characterize the running-in process.
Practical implications
The study reveals that the application EEMD method is an appropriate approach to reconstruct frictional vibration and the information entropy of friction vibration represents the running-in process. Based on these results, a condition monitoring system can be established to automatically evaluate the running-in state of mechanical parts.
Originality/value
The EEMD method was applied to reconstruct the frictional vibration. Furthermore, the information entropy of friction vibration was used to analysis the running-in process.
Details
Keywords
Haijie Huang, Changjiang Lyu and Xiaowen Zhu
The purpose of this paper is to study the effect of second generation involvement on corporate innovation in Chinese family firms.
Abstract
Purpose
The purpose of this paper is to study the effect of second generation involvement on corporate innovation in Chinese family firms.
Design/methodology/approach
Based on the manually collected sample of listed Chinese family firms from 2003 to 2014, the study empirically examines the impact of second generation involvement on corporate innovation. The authors apply a difference-in-differences research design and a Heckman two-stage least squares regression to relieve the endogeneity concerns.
Findings
The research finds a positive relationship between second generation involvement and corporate innovation. This effect is more pronounced among the firms appointing second generation family members with overseas training experience and firms with weak external monitoring. Further analysis shows that the curtailment of related party transactions and the improvement of accounting information quality are important channels.
Practical implications
The findings provide several practical implications for Chinese family firms to survive the succession process and maintain competitive advantages across generations.
Originality/value
First, this study is helpful to understand the strategies adopted by family firms to maintain their long-term competitiveness and pursue continuing growth across generations. Second, the findings are also consistent with the transfer cost hypothesis of Fan et al. (2012) and Bennedsen et al. (2015). Finally, the findings imply that second generation involvement has a substitutive effect for external monitoring mechanisms.