scholarly journals Study of the Lifetime Testing of Spherical Rubber Isolators

2021 ◽  
Vol 11 (15) ◽  
pp. 6667
Author(s):  
Hao Li ◽  
Chengliang Yang ◽  
Shaoxin Wang ◽  
Ping Su ◽  
Xingyun Zhang ◽  
...  

This study aims to identify the fatigue lifetime of a thin-walled hollow spherical rubber isolator subjected to harmonic and random vibrations. Firstly, the nonlinear characteristics of the rubber materials are tested and analyzed through vibration experiments. The relationship among the nonlinear stiffness, nonlinear damping, and relative displacement amplitude is established. Secondly, an accelerated lifetime experiment under random excitation is carried out. The correlation between the root-mean-squared acceleration response of the random vibration system and the stiffness attenuation of the rubber isolator is established and modeled. A lifetime prediction method for rubber isolators is proposed based on the model. Finally, the influence of different loads on the lifetime of the rubber isolator is investigated. These methods provide an additional rationale for the further theoretical research and practical engineering application of rubber damping systems.

2012 ◽  
Vol 446-449 ◽  
pp. 1432-1436
Author(s):  
Suo Wang

In order to predict tunnel surrounding rock pressure, this paper puts forward a series of dynamic numerical simulative model on the tunnel excavation. According to the change of rock damage in the construction program, it adjusts dynamically the mechanical material parameters of surrounding rock. So the model achieves the purpose which is controlling and simulating the process of tunnel progressive damage. In accordance with the numerical simulative results, it analyzes the relationship between the rock parameters with the plastic strain, radial displacement. Then this paper proposes a prediction method of tunnel surrounding rock pressure based on the theory of the progressive damage and method of characteristic curve. Finally, it compares the pressure on the numerical simulative models with on the site date, and it proves that the prediction method has practical engineering value.


2011 ◽  
Vol 105-107 ◽  
pp. 20-23 ◽  
Author(s):  
Yan Guo Zhou ◽  
Wen Zhong Qu ◽  
Li Xiao

The hysteresis dynamic behavior of metal rubber mathematically modeled with a practical method is studied, and the method of parameter separated identification is presented with details. Parameters of the model are identified with the test data of metal rubber, from which the theoretical loops are reconstructed, and the mechanism of the nonlinear damping behavior of the metal rubber is investigated. The theoretical loops and the experimental one are close to each other with satisfactory accuracy. The result shows that with the simple mathematical form and the satisfactory precision, the mixed damping model can be used effectively in practical engineering. This study provides a practical and effective method in modeling and the parameter identification of the metal rubber isolator.


2014 ◽  
Vol 945-949 ◽  
pp. 261-265
Author(s):  
Yan Su Hu ◽  
Ang Gao ◽  
De Jun Mu

The high-speed Flat Sewing Machine is the most widely used macaronis full-automation Sewing Machine. The sewing tasks are intermittent which leads to a frequent actuation and long operating time of the magnetic valve. It puts higher requirements on the magnetic valve. Based on this problem, this paper adopt the RDC Clamped Circuit to reduce the turn-off loss and suppress the drain voltage of MOSFET rising. First analyze the turn-off loss of RDC circuit and the PWM characteristics, and then deduce the relationship between the parameters of RDC circuit and the controller by theoretical calculation. Finally, the experiments prove the validity and effectiveness of the method, and also offer a theoretical foundation for the practical engineering application.


2015 ◽  
Vol 741 ◽  
pp. 411-415
Author(s):  
Shu Zheng Shi ◽  
Shao Lei Wang ◽  
Ming Xing Song ◽  
Zhen Zhen Huo

Based on nonlinear damping and stiffness consideration between not only work rolls but also back-up roll and body frame, five times frequency flutter model of rolling mill was built according to actual structure of rolling mill, which followed by simulation analysis. Some theoretical guidance can be provided for practical engineering application.


2018 ◽  
Vol 207 ◽  
pp. 04007
Author(s):  
Lei Sun ◽  
Lin Tao ◽  
Yonghui xie ◽  
Yuanjian Dang ◽  
Yongqing Wang

The S-CO2 Brayton cycle system has many characteristics such as low cost and compact structure, and is one of the hotspots in the fields of waste heat utilization, new energy and so on. In this paper, a mathematical model of the S-CO2 simple Brayton cycle is constructed, and the cyclic characteristics are analysed. The relationship between the component parameters of the system and the calculation parameters of the cycle such as the cycle efficiency and the output net work are obtained under the design conditions. Meanwhile, calculation models of turbine and compressor under off-design conditions are established, and the characteristics of the whole cycle are analyzed. Thus, the characteristics of off-design conditions of the simple cycle are obtained. This study provides some reference for the related research of the S-CO2 Brayton cycle and the practical engineering application.


2012 ◽  
Vol 614-615 ◽  
pp. 1069-1074
Author(s):  
Jun He ◽  
Xu Na Liu ◽  
Li Ping Chen

To meet power customers’ satisfaction is the essential responsibilities of utilities. Considering the property of customer’s satisfaction degree, an analytical interval assessment method of voltage sag is proposed. The customer satisfaction degree is presented by interval number corresponding to the voltage tolerance for the tested equipment installed at the customer side. Based on the determination function derived from the relationship between the voltage magnitude and the length of fault line in the power system, critical fault positions are determined through analytical iterative algorithm. By the variation of satisfaction degree within a given interval, the interval sag frequency is calculated. Moreover, the quantitative sag frequency is determined by the help of the interval sag frequency. The proposed method is applied to a five-bus system and IEEE 30-bus testing system. The simulation results comparing with existing methods have shown that this method is credible and suitable for the practical engineering application.


Author(s):  
Natalia Popova

The concept of Europeanization has become quite fashionable in EU studies in recent years. It is often used for the analysis of the relations between the EU and non-member states. The aim of the article is to examine the possibilities of its application in explaining the relationship between the EU and Ukraine. The structure of the article is as follows: firstly, the concept of Europeanization is defined considering such two disputable issues as distinguishing among concepts of Europeanization and European integration as well as Europeanization and EU-ization. Next, the evolution of the theoretical research of Europeanization and definition of this concept are analyzed. Two main mechanisms of Europeanization (conditionality and socialization) are examined. The author considers main approaches to the analysis of the "external" Europeanization emphasizing the concept of "external governance". Three groups of factors which influence the effectiveness of Europeanization are briefly analyzed. And finally, the peculiarities of application of the Europeanization concept to the Ukraine-EU relations are outlined. Keywords: EU, Ukraine, Europeanization, EU-ization, ‘external’ Europeanization, conditionality, socialization, concept of ‘external governance’


2021 ◽  
pp. 1-13
Author(s):  
Hajar Boutmaghzoute ◽  
Karim Moustaghfir

BACKGROUND: This study builds on the little guidance in the existing literature to analyze the relationship between employee-oriented CSR actions and employee retention in a business context, while using Freeman stakeholders’ model as a theoretical research framework. This research also aims to shed light on significant behavioral factors facilitating the relationship between CSR endeavors and turnover rate. OBJECTIVE: This paper builds on the existing research gap in the literature and suggests that behavioral factors, including job satisfaction, organizational identification, and motivation facilitate the relationship between employee-oriented CSR actions and employee retention, which contributes to laying the foundations of a theoretical framework that has the potential to advance both theoretical and practitioner debates and disentangle the complexity of such a relationship, while offering strategically-focused development venues in CSR and HRM fields. METHODS: This research uses a single case study design to ensure an in-depth and detailed analysis of the phenomenon under scrutiny, while relying on a triangulation methodology for data collection, including a questionnaire used as exploratory approach, interviews to generate explanatory data, and archival data to bring confirmatory insights. Data analysis followed the procedures of a deductive approach. RESULTS: The research results show a positive relationship between employee-oriented CSR actions and employee retention, while demonstrating the facilitating role of job satisfaction, organizational identification, and motivation in moderating such a relationship. The findings also stress the importance of framing CSR interventions within the organization’s strategy and goals, while ensuring employee participation in such decision making processes to maximize the effect of CSR interventions on employee commitment and reduce turnover. CONCLUSIONS: This research has the potential to better clarify the nature of the relationship involving CSR interventions, from an employee perspective, retention, and turnover, while laying the foundations of a theoretical framework linking such constructs and other behavioral factors that underpin and support such a relationship. Building on the study’s findings and assumptions, future research is needed to gain a more comprehensive understanding of how HR-related CSR actions affect behavioral performance dimensions, resulting in employee commitment and retention. Future research should also consider multiple case study, multicultural, and ethnographic approaches for the sake of generalizability and theory building.


2019 ◽  
Vol 43 (4) ◽  
pp. 535-543 ◽  
Author(s):  
Shunxin Cao ◽  
Ruijun Zhang ◽  
Shuohua Zhang ◽  
Shuai Qiao ◽  
Dongsheng Cong ◽  
...  

Interaction and wear between wheel and rail become increasingly serious with the increase in elevator speed and load. Uneven roller surface, eccentricity of rollers, and the looseness of rail brackets result in serious vibration problems of high-speed and super-high-speed elevators. Therefore, the forced vibration differential equation representing elevator guide rails is established based on Bernoulli–Euler theory, and the vibration equation of the elevator guide shoes and the car is constructed using the Darren Bell principle. Then, the coupled vibration model of guide rail, guide shoes, and car can be obtained using the relationship of force and relative displacement among these components. The roller–rail parameters are introduced into the established coupled vibration model using the model equivalent method. Then, the influence of roller–rail parameters on the horizontal vibration of super-high-speed elevator cars is investigated. Roller eccentricity and the vibration acceleration of the car present a linear correlation, with the amplitude of the car vibration acceleration increasing with the eccentricity of the roller. A nonlinear relationship exists between the surface roughness of the roller and the vibration acceleration of the car. Increased continuous loosening of the guide rail results in severe vibration of the car at the loose position of the support.


Sign in / Sign up

Export Citation Format

Share Document