Haixu Yang, Feng Zhu, Haibiao Wang, Liang Yu and Ming Shi
The purpose of this paper is to describe the structure of nonlinear dampers and the dynamic equations, and nonlinear realization principles and optimize the parameters of…
Abstract
Purpose
The purpose of this paper is to describe the structure of nonlinear dampers and the dynamic equations, and nonlinear realization principles and optimize the parameters of nonlinear dampers. Using the finite element method to analyze the seismic performance of the frame structure with shock absorber.
Design/methodology/approach
The nonlinear shock absorber was installed in a six-storey reinforced concrete frame structure to study its seismic performance. The main structure was designed according to the eight degree seismic fortification intensity, and the time history dynamic analysis was carried out by Abaqus finite element software. EL-Centro, Taft and Wenchuan seismic record were selected to analyze the seismic response of the structure under different magnitudes and different acceleration peaks.
Findings
Through the principle study and parameter analysis of the nonlinear shock absorber, combined with the finite element simulation results, the shock absorption performance and shock absorption effect of the nonlinear energy sink (NES) nonlinear shock absorber are given as follows: first, the damping of the NES shock absorber is satisfied, and the linear spring stiffness and nonlinear stiffness of the shock absorber are based on the relationship k1=kn×kl2, so that the spring design length is fixed, and the linear stiffness of the shock absorber can be obtained. The nonlinear shock absorber has the characteristics of high rigidity and frequency bandwidth, so that the frequency is infinitely close to the frequency of the main structure, and when the mass of the shock absorber satisfies between 0.056 and 1, a good shock absorption effect can be obtained, and the reinforced concrete with the shock absorber is obtained. The frame structure can effectively reduce the seismic response, increase the natural vibration period of the structure and reduce the damage loss of the structure. Second, the spacer and each additional shock absorber have a small difference in shock absorption effect. After the shock absorber parameters are accurately calculated, the number of installations does not affect the shock absorption effect of the structure. Therefore, the shock absorber is properly constructed and accurately calculated. Parameters can reduce costs.
Originality/value
New shock absorbers reduce earthquake-induced damage to buildings.
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Haixu Bao, Chunhsien Wang and Ronggen Tao
This study aims to explore the relationship between geographic search and business model innovation and proposed a contingent framework to focus on how governmental networking and…
Abstract
Purpose
This study aims to explore the relationship between geographic search and business model innovation and proposed a contingent framework to focus on how governmental networking and environment turbulence are interdependent moderate the relationship between geographic search and business model innovation.
Design/methodology/approach
A large-scale questionnaire survey was carried out among the firms in three high-tech parks of the Pearl River Delta, with a total of 287 firms as empirical samples. Hypotheses are tested using ordinary least squares analyzes on hierarchical multiple regression to find out how geographic search can drive business model innovation generations.
Findings
The empirical results showed that the more frequent geographic search is, the more favorable it is for firms to generate innovative business models, and firms may be more effective in geographic searching and business model innovation with better governmental networking. However, the above relationship may be weakened if the environment turbulence in emerging markets is further considered. It was argued that firms must take into account both the positive effects of governmental networking and the negative effects of environmental turbulence in conducting a geographic search for external knowledge resources to generate innovative business models. The study results showed how and why governmental networking can be a key catalyst for firms to generate innovative business models.
Research limitations/implications
This study contributes to the business model innovation literature by documenting the large-scale survey evidence that confirms the practicality of geographic search in the business model innovation generations. The findings advance previous studies in the business model innovation by identifying the moderating roles of governmental network and environment turbulence that predict business model innovation behaviors in the emerging market.
Practical implications
The results indicate that the geographic search can be easily operationalized for external resources acquisitions by managers in generating business model innovation. This has applications for external resource acquisitions on the basis of business model innovation in the emerging China market. In addition, to facilitate the business model innovation generations, the focus should be on critical contingency factors; on the one hand, to promote the continued use of external resources, the focus should be on enhancing benefits such as governmental networking.
Originality/value
The findings extend existing theory in three ways as the original value. First, the results show that geographic search is an important driver of business model innovation generations in an emerging market context. Second, this study is the first to take organizational learning and open innovation perspective to examine geographic search as a boundary-spanning search of external resources in business model innovation generations. Third, this study also explores the moderator role of governmental network and environmental turbulence on how to strengthen or impair the geographic search and business model innovation generations.
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Haixu Bao, Haizhen (Jane) Wang and Chenglin Sun
The purpose of this paper is to explore how middle managers respond to the career challenges caused by environmental regulation. In particular, this paper examines whether…
Abstract
Purpose
The purpose of this paper is to explore how middle managers respond to the career challenges caused by environmental regulation. In particular, this paper examines whether environmental regulation strength is positively related to middle managers’ openness toward change, and whether middle managers’ openness toward change is positively related to proactive behavior. Furthermore, the moderating role of top managers’ bottom-line mentality in these two relationships is examined.
Design/methodology/approach
Cross-sectional survey research (n=155) was conducted. During a training program, data were collected from 155 middle managers from a listed company that manufactures primary products. With these data the authors examined the main relationship and also explored the moderating effect of top managers’ bottom-line mentality.
Findings
Analysis of the findings indicates that perceived environmental regulation strength influences middle managers’ openness toward change and consequently their proactive behavior. In addition, top managers’ bottom-line mentality moderates both the link between environmental regulation strength and openness toward change and the link between openness toward change and proactive behavior.
Originality/value
The findings of this study reveal how environmental regulation induces middle managers’ proactive behavior, and the influence of top managers’ mentality on how middle managers respond to environmental regulation both cognitively and behaviorally.
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Yufeng Guo, Chuang Zhang, Lei Qi, Haixu Yu, Suzhen Liu and Liang Jin
The purpose of this study is to develop an electromagnetic loading method for online measurement of the acoustoelastic coefficients and bus bar plane stress.
Abstract
Purpose
The purpose of this study is to develop an electromagnetic loading method for online measurement of the acoustoelastic coefficients and bus bar plane stress.
Design/methodology/approach
A method based on the combination of electromagnetic loading and the acoustoelastic effect is proposed to realize online measurement of acoustoelastic coefficients and plane stress. Electromagnetic loading is performed on the bus bar specimen, and the acoustoelastic coefficients and the bus bar plane stress are obtained by the ultrasonic method. An electromagnetic loading experimental platform is designed to provide electromagnetic force to the metal plate, including an electromagnetic loading module, an ultrasonic testing module and a stress simulation module.
Findings
The feasibility of the proposed electromagnetic loading method is proved by verification experiments. The acoustoelastic coefficients and plane stress measured using the electromagnetic loading method are more accurate than those measured using the traditional method.
Originality/value
The proposed electromagnetic loading method provides a new study perspective and enables more accurate measurement of the acoustoelastic coefficients and plane stress. The study provides an important basis for evaluating the operation status of electrical equipment.
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Yanfu Wang, Xin Wang and Lifei Liu
Lapping is a vital flattening process to improve the quality of processed semiconductor wafers such as single-crystal sapphire wafers. This study aims to optimise the lapping…
Abstract
Purpose
Lapping is a vital flattening process to improve the quality of processed semiconductor wafers such as single-crystal sapphire wafers. This study aims to optimise the lapping process of the fixed-abrasive lapping plate of sapphire wafers with good overall performance [i.e. high material removal rate (MRR), small surface roughness (Ra) of the wafers after lapping and small lapping plate wear ratio (η)].
Design/methodology/approach
The influence of process parameters such as lapping time, abrasive size, abrasive concentration, lapping pressure and lapping speed on MRR, Ra and η of lapping-processed sapphire wafers was studied, and the results were combined with experimental data to establish a regression model. The multi-evaluation index optimisation problem was transformed into a single-index optimisation problem via an entropy method and the grey relational analysis (GRA) to comprehensively evaluate the performance of each parameter.
Findings
The results revealed that lapping time, abrasive size, abrasive concentration, lapping pressure and lapping speed had different influence degrees on MRR, Ra and η. Among these parameters, lapping time, lapping speed and abrasive size had the most significant effects on MRR, Ra and η, and the established regression equations predicted the response values of MRR, Ra and η to be 99.56%, 99.51% and 93.88% and the relative errors between the predicted and actual measured values were <12%, respectively. With increased lapping time, MRR, Ra and η gradually decreased. With increased abrasive size, MRR increased nearly linearly, whereas Ra and η initially decreased but subsequently increased. With an increase in abrasive concentration, MRR, Ra and η initially increased but subsequently decreased. With increased lapping pressure, MRR and η increased nearly linearly and continuously, whereas Ra decreased nearly linearly and continuously. With increased lapping speed, Ra initially decreased sharply but subsequently increased gradually, whereas η initially increased sharply but subsequently decreased gradually; however, the change in MRR was not significant. Comparing the optimised results obtained via the analysis of influence law, the parameters optimised via the entropy method and GRA were used to obtain sapphire wafers lapping with an MRR of 4.26 µm/min, Ra of 0.141 µm and η of 25.08, and the lapping effect was significantly improved.
Originality/value
Therefore, GRA can provide new ideas for ultra-precision processing and process optimisation of semiconductor materials such as sapphire wafers.