Modal Testing and Finite Element Analysis of a Battery Rack for Seismic Applications

2005 ◽  
Vol 48 (1) ◽  
pp. 94-102 ◽  
Author(s):  
Elzbieta Berak

One of the most challenging aspects of reliability testing in the telecommunication industry is earthquake resistance testing. Cabinet systems, battery racks, equipment racks, and distribution frames are considered compliant with Network Equipment-Building System (NEBSTM) criteria for surviving earthquake conditions if test results indicate (1) the maximum deflection of the top of the structure does not exceed 7.6 cm (3 in.), (2) there are no permanent deformations or structural damage, and (3) the equipment or batteries remain functional (as defined in NEBS Requirements: Physical Protection, Specification GR-73 Issue 2). Based on seismic test results of a large population of telecom enclosures, it is accepted that a system always passes the seismic test if its fundamental natural frequency is at least 6 Hz. It is costly to produce and configure enclosures and conduct seismic qualification testing. To minimize the risk of telecom system failure, a modal finite element analysis (FEA) of the system should first be performed. Numerical results of the FEA should then be verified with experimental resonance search data generated by modal testing or sine sweep testing, combined with static pull testing where applicable. The resonance search results will determine the need for seismic testing (seismic analysis) prior to seismic qualification testing. This paper elaborates on key aspects of the static pull test method supported by the test results for a cabinet framework and a configured cabinet relative to the seismic test results. The paper also discusses sine sweep testing of a battery cabinet and results of two modal test methods used on the corresponding battery rack. Finally, this paper describes modal FEA of the same battery rack anchored to a concrete pad supported by a polystyrene plastic foam sheet and explains the correlation of the numerical results with the experimental modal analysis results. The correlated model serves as the baseline model for analyzing other battery racks and equipment cabinets configured with batteries.

Author(s):  
Youngik Yoo ◽  
Kyounghong Kim ◽  
Kyongbo Eom ◽  
Seongki Lee ◽  
Jongsung Yoo

Spent nuclear fuel (SNF) integrity evaluation related to its handling and transportation for mid-/long-term dry storage is a regulatory requirement. Especially, a drop event is the most fatal failure mode among regulatory conditions. For SNF drop accidents, it is required that the mechanical integrity of the SNF be evaluated using test results or analytic methodologies. The SNF mechanical test, however, takes much time and cost, and there are safety issues related to the release of radioactive materials. Thus, finite element analysis is used as an alternative to the experimental test method to solve this problem. In this study, a three dimensional (3D) finite element model was developed using ABAQUS software to simulate the structural behaviors of a fresh fuel assembly (FA) prior to applying SNF properties because of a lack of SNF test results. Static and dynamic mechanical behaviors were simulated with this model and compared with the fresh FA test results. The analysis results are in good agreement with the test results. Therefore, the analysis model consistent with the test results will be applied to the evaluation of the FA drop integrity reflecting the specific SNF characteristics.


2011 ◽  
Vol 243-249 ◽  
pp. 1461-1465
Author(s):  
Chuan Min Zhang ◽  
Chao He Chen ◽  
Ye Fan Chen

The paper makes an analysis of the reinforced concrete beams with exterior FRP Shell in Finite Element, and compares it with the test results. The results show that, by means of this model, mechanical properties of reinforced concrete beams with exterior FRP shell can be predicted better. However, the larger the load, the larger deviation between calculated values and test values. Hence, if more accurate calculation is required, issues of contact interface between the reinforced concrete beams and the FRP shell should be taken into consideration.


2020 ◽  
Vol 12 (5) ◽  
pp. 168781402091868
Author(s):  
Shuang Jing ◽  
Anle Mu ◽  
Yi Zhou ◽  
Ling Xie

The seal is the key part of the cone bit. To reduce the failure probability, a new seal was designed and studied. The sealing performance and structure optimization of the X-O composite seal was analyzed and compared by finite-element analysis. The stress and contact pressure were analyzed to establish the main structural parameters that affect sealing performance and the direction of the structural optimization. By optimizing these structural parameters, including the height, and the radial and axial arc radii, an optimized structure is obtained. The results show that (1) the X-O composite seal can meet the seal requirement, the excessive height of the X seal ring is the root cause of the uneven distribution of stress, pressure, and distortion. (2) A new seal structure is obtained, the distribution of pressure and stress is reasonable and even, and the values of stress and pressure are reduced to avoid distortion and reduce the wear. Finally, the field test results of the X-O composite seal of cone bit showed that the service life of the bit bearing increased by 16% on average and the drilling efficiency increased by 11% on average compared with the original cone bit with the O seal ring.


2014 ◽  
Vol 580-583 ◽  
pp. 2134-2140
Author(s):  
Jian Zhang ◽  
Jian Feng Zhai ◽  
Xian Mei Wang ◽  
Jie Chen

Two-Dimensional finite element analysis was used to investigate the performance of seawall construction over weak subgrade soil using artificial base layer material consisted of cemented sand cushion comprising geosynthetics materials. Two types of base layer materials pure sand and cemented sand comprising husk rich ash and two types of geosynthetics materials geogrid and geotextile were used. Constitutive models were used to represent different materials in numerical analysis. The competence of two-dimensional numerical analysis was compared with experimental results. Numerical results showed a superior harmony with the experimental results. Finite element analysis model proved to be a great tool to determine the parameters that are difficult to measure in laboratory experiments. In addition, finite element analysis has the benefit of cost and time saving when compared to experimental investigation work. Numerical results showed strain induced in geosynthetics eliminated beyond a distance approximately equal six times of footing width.


Author(s):  
Liangyao Yu ◽  
Liangxu Ma ◽  
Jian Song

This paper presents a new approach to the design, testing and analysis of a magnetorheological brake which uses a multi-path magnetic circuit to satisfy the braking demand of vehicles. In contrast with a general braking system, an automotive brake exhibits an outstanding performance for high torques and long reaction times. We use a proposed power-law model and finite element analysis to obtain the magnetorheological braking performance for a high shear rate and a high-intensity magnetic field. Finite element analysis with different structures is adopted to determine the parameters of the magnetorheological braking and the layout of the magnetic circuits. An integrated prototype is also fabricated and tested. The test results show that the brake torque is relatively high, and the torque can be accurately controlled by the input current. The reaction time is less than 100 ms. We also analyse the experimental results and use these as the basis for fabricating a full-sized prototype. The full-sized prototype generally exhibits a high torque capacity and a fast dynamic response, thereby validating the feasible application of magnetorheological fluids in automotive braking.


2011 ◽  
Vol 474-476 ◽  
pp. 807-810 ◽  
Author(s):  
Xiao Cong He

This paper deals with the effects of bending and boundary condition on the stress distribution of a single-lap adhesive joint under tension using the three-dimensional finite element analysis technique. The numerical results obtained from the finite element analysis show that both the left and right hand regions of the adhesive layer are subjected to high stresses. The numerical results also show that most of the extreme stresses occur at interface which is between the adhesive and the upper adherend. It is clear that the stresses are concentrated near the left and right free ends of the adhesive layer while the centre region of the adhesive layer is mostly stress-free. It is also clear that the stress state in this case is mainly dominated by the normal stress components.


2013 ◽  
Vol 275-277 ◽  
pp. 1359-1363 ◽  
Author(s):  
Jeong Soo Kim ◽  
Moon Kyum Kim

Owing to strong nonlinearity of shotcrete and difficulty of determining the equivalent material properties of steel-shotcrete composites for numerical analysis, methods are required to estimate nonlinear behavior of steel-shotcrete composite in the computational aspect efficiently. In this study, the behavior of steel-shotcrete composites, main primary supports in the NATM tunnel, are estimated by finite element method using the fiber beam-column element. The numerical results are compared with results of uniaxial and flexural test. Results of comparison show that finite element analysis of using fiber beam-column element can be an efficient tool of estimating the steel-shotcrete composite as the primary support in the NATM tunnel.


2012 ◽  
Vol 24 (1) ◽  
pp. 49-60 ◽  
Author(s):  
Bintang Yang ◽  
Tianxiang Chen ◽  
Guang Meng ◽  
Zhiqiang Feng ◽  
Jie Jiang ◽  
...  

In this research, a novel safety escape device based on magnetorheological fluid and permanent magnet is designed, manufactured, and tested. The safety escape device with magnetorheological fluid and permanent magnet can provide an increasing braking torque for a falling object by increasing the magnetic field intensity at the magnetorheological fluid. Such increase is realized by mechanically altering the magnetic circuit of the device when the object is falling. As a result, the falling object accelerates first and then decelerates to stop in the end. Finite element analysis is used to determine some of the specifications of the safety escape device for larger braking torque and smaller size. Finite element analysis results are also used for theoretical study and establishment of the dynamic model of the safety escape device. A prototype is realized and tested finally. The experimental test results show that the operation of the prototype conforms to the prediction by the dynamic model and validates the feasible application of magnetorheological fluids in developing falling devices.


Sign in / Sign up

Export Citation Format

Share Document