This article studies the application of fiber Bragg grating sensors in damage monitoring of sandwich composite L-joints, which aims to reveal the interface damage between the GFRP skin and the foam core. Fiber Bragg grating sensors have been arranged based on numerical results. The ultimate load and failure location via numerical modelling have been experimentally verified. Strains measured by fiber Bragg grating sensors have shown anomalies with load increased, indicating the onset and propagation of damage. Based on the damage-induced strain anomalies, four stages have been addressed to reveal the emergence, accumulation and propagation of damage during the loading process. Measurements by numerical simulation and surface mounted strain gauges have been found to be less sensitive to internal damage, proving the great significance of embedding fiber Bragg grating sensors to monitor interface damages of sandwich L-joint.

To demonstrate how cognitive well-being effectively occurs, this study examines the interactive effects of relational energy on cognitive well-being. Based on conservation of resource (COR) theory, this study expands understanding of the relationship between leader relational energy and employee cognitive well-being, using 245 employees as the sample in the experiment of exploring the mediation role of work absorption. Meanwhile, the significance of co-worker relational energy is highlighted as a key boundary condition for effective leader relational energy. The results of a three-wave time study in China showed that employee work absorption played a mediating role between leader relational energy and employee cognitive well-being. In addition, co-worker relational energy moderated the relationship between leadership relational energy and work absorption. This study provides novel insights into management practice for leaders to improve employee cognitive well-being.

Against the backdrop of an aging global population and the increasing pressure of medical care expenditures for seniors, this paper used a fuzzy regression discontinuity (FRD) model to explore the effects of retirement on the self-assessed health and objective physical and mental health of older people. Using survey data from the China Health and Retirement Longitudinal Study (CHARLS), our model addresses some relevant academic controversies. Our sample was comprised of male respondents from government agencies, enterprises, and public institutions. The research explored the impact of retirement on lifestyle habits and included an in-depth analysis of the mechanism through which retirement influences different aspects of health. The results show that: (1) Retirement does not have any significant impact on objective health, including depression and self-care ability, but it does cause a notable decline in subjective health assessment. (2) Retirement shortened the sleep time of respondents, which may account for lower scores on subjective health self-evaluations, but it did not lead to any noticeable improvement in habits which are harmful to health, such as smoking and drinking. (3) Marriage can help alleviate the problems of depression and smoking among older people, and education has a somewhat broader positive effect on their health and lifestyles; however, neither factor helps to improve the sleep problems of older people. Therefore, this paper recommends that efforts should be made to both optimize retirement policies and seek further ways to improve the health of the retired population.

This paper studies the compressive failure behavior of pw-GFRP (plain-woven glass fiber reinforced polymer) sandwich composite L-joints for ships. Six L-joint specimens were subjected to ultimate compressive tests, which show that damage and stiffness degradation started much earlier than any visible signs. A modified fiber kinking criterion is developed for the compressive failure of pw-GFRP layup structure. Moreover, a hybrid stiffness degradation model is applied to simulate the damage progression. The criterion and the degradation model are implemented in simulation through Abaqus user coding. The simulation results are compared with other existing theories, and the proposed criterion is validated by the similar damage initiation time. The combination of the proposed criterion and hybrid degradation model demonstrates a clear advantage over conventional methods in predicting the compressive damage evolution and ultimate failure behavior of the L-joint structure.