Study of Reactor Internal Bolt Behaviors Under Lateral Loads

2017 ◽  
Author(s):  
Yong-Jian Gao ◽  
Shao-Dong Feng ◽  
Qing Yu ◽  
Bing-Bing Chen ◽  
Shao-Xuan Lin ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Cantilever Beam ◽  
Lateral Load ◽  
Test Results ◽  
Lateral Loads ◽  
Stress Calculation ◽  
Thermal Movement ◽  
Bolt Stress ◽  
Beam Mode

In calculating the bolt stresses under lateral loads, such as caused by the differential thermal movement between two components — problems often found in the reactor internal design, the boundary condition of the bolt is usually conservatively assumed to be in a guided-cantilever beam mode, i.e., the bolt head is not allowed to rotate. In reality, the bolt head could rotate to a certain degree and, furthermore, the bolt head could slip, a form of loosening, under the lateral loads. A series of lateral load-deflection tests was conducted on bolts of different sizes and different lengths, with different preloads, to study the bolt behaviors, including when the bolts start to slip and what is the effect of preloading on the slippage. Furthermore, finite element studies were conducted to correlate the test results to find the proper boundary condition to be used in the bolt stress calculation.

Study of Alternative Assembly Patterns Using Finite Element Analysis and Lab Tests

2018 ◽  
Author(s):  
Gong H. Jung ◽  
Wesley Pudwill ◽  
Elysia J. Sheu
Keyword(s):  
Finite Element ◽  
Elastic Interaction ◽  
Element Model ◽  
Potential Method ◽  
Test Results ◽  
Element Analysis ◽  
Fea Model ◽  
Assembly Method ◽  
Bolt Stress ◽  
Lab Test

A total of 24 lab tests were performed to evaluate two different joint assembly patterns (legacy and an alternative pattern), two lubricant types (Nickel based and Moly-Disulphide based), and two types of torque wrenches (Hydraulic and Pneumatic). Bolt stress was measured during assembly using load indicating bolts (SPC4). Assembly time was also measured since alternative assembly patterns have been recognized as a potential method for improving assembly efficiency without negatively impacting bolt pre-load scatter. In order to understand the bolt stress distribution in both of the legacy and alternative assembly patterns, a finite element model was developed to simulate wrench sequences specified by ASME PCC-1. The FEA model included the effect of elastic interaction of the bolts and flange. The FEA results indicate similar behavior when compared to the lab test results, and the FEA study was extended to two other alternative assembly patterns. This paper summarizes the results of the FEA and lab tests on a 24” NPS Class 300 flange and may provide validation and supporting information for users who are considering the use of a more efficient assembly method such as the alternative assembly patterns presented in ASME PCC-1.

Study on Safety of the Fastener Tubular Steel Scaffolding

2011 ◽  
Vol 368-373 ◽  
pp. 771-776 ◽  
Author(s):  
Chang Ming Hu ◽  
Fang Fang Song ◽  
Xiao Zhou Fan
Keyword(s):  
Finite Element ◽  
Initial Imperfection ◽  
Full Scale ◽  
Scale Model ◽  
Test Results ◽  
Lateral Loads ◽  
Safety Control ◽  
Research Results ◽  
Initial Imperfections ◽  
Finite Element Software

Based on analysis of five different conditions’ full scale model tests of the fastener tubular steel scaffolding, the paper introduces that notional lateral loads can imitate the effect which generalized imperfections of the falsework(initial imperfections, node semi-rigid and so on) give the bracket’s stability capacity. According to the finite element software ANSYS, the falseworks’ stability capacities of different conditions have been imitated and analysed, Analysis results compare with test results. The final result indicates that it is reasonable that notional lateral loads in certain scope can imitate generalized initial imperfection. Research results can be used for on-site t technical personnels’ design and safety control.

scholarly journals Structural behaviour of insulated foam-timber panels under gravity and lateral loading

2021 ◽  
Author(s):  
Hassan Abbasi
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Lateral Load ◽  
Expanded Polystyrene ◽  
Load Test ◽  
Residential Construction ◽  
Test Results ◽  
Cyclic Lateral Load ◽  
Modification Factor ◽  
Experimental Findings

A Structural Insulated Panel (SIP) is a structural element of expanded polystyrene insulation (EPS) core sandwiched between two oriented-strand boards (OSB). This research proposes SIPs in low-rise residential construction (i.e. houses and low-residential building), replacing the traditional conventional joist floors and stud walls. This research investigates (i) developing expressions for flexural, compression, monotonic racking and cyclic lateral load capacities of SIPs as compared to the joist/stud wall construction. In this study, the proposed design of SIPs was based on (i) generally established theory for analysis, (ii) assessment of full-scale SIP panels by a loading tester, and (iii) computer modeling using the finite-element modeling. The research program included (i) testing SIP walls in axial compression and bending, (ii) racking and cyclic testing on SIP shear walls, (iii) development of finite-element computer models of the tested SIP panels and verifying those using experimental findings, (iv) correlation between experimental findings and design equations for strength and serviceability available in the literature and wood design Standards. Modification factors of these equations were developed to allow structural engineers to design SIP panels in residential construction more economically reliably. Experimental results showed that SIP panels are being “as good as” the conventional wood-framing of identical sizes, with respect to flexural, compressive, racking and cyclic loading. Also, results showed SIP walls have a greater ability to dissipate energy under racking and cyclic loading that the stud wall system. Therefore, SIP walls can be used so efficient in seismic zones. Based on cyclic lateral load test results, the values of ductility-related force modification factor (Rd) for stud wall, short SIP wall and long SIP wall were calculated as 8%, 22% and 14% lower than the NBCC required value for anchored wall (Rd = 3.0), respectively. In addition cyclic lateral load test results showed that the values of over-strength-related force modification factor (Ro) for stud wall, short SIP wall and long SIP wall were observed to be 17%, 20% and 14% higher than the recommended value of NBCC (Ro = 1.7) for anchored wall, respectively. So, it is concluded that the over-strength factor indicates a confident reserve of resistance in interconnected wall segments.

scholarly journals Structural behaviour of insulated foam-timber panels under gravity and lateral loading

2021 ◽  
Author(s):  
Hassan Abbasi
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Lateral Load ◽  
Expanded Polystyrene ◽  
Load Test ◽  
Residential Construction ◽  
Test Results ◽  
Cyclic Lateral Load ◽  
Modification Factor ◽  
Experimental Findings

A Structural Insulated Panel (SIP) is a structural element of expanded polystyrene insulation (EPS) core sandwiched between two oriented-strand boards (OSB). This research proposes SIPs in low-rise residential construction (i.e. houses and low-residential building), replacing the traditional conventional joist floors and stud walls. This research investigates (i) developing expressions for flexural, compression, monotonic racking and cyclic lateral load capacities of SIPs as compared to the joist/stud wall construction. In this study, the proposed design of SIPs was based on (i) generally established theory for analysis, (ii) assessment of full-scale SIP panels by a loading tester, and (iii) computer modeling using the finite-element modeling. The research program included (i) testing SIP walls in axial compression and bending, (ii) racking and cyclic testing on SIP shear walls, (iii) development of finite-element computer models of the tested SIP panels and verifying those using experimental findings, (iv) correlation between experimental findings and design equations for strength and serviceability available in the literature and wood design Standards. Modification factors of these equations were developed to allow structural engineers to design SIP panels in residential construction more economically reliably. Experimental results showed that SIP panels are being “as good as” the conventional wood-framing of identical sizes, with respect to flexural, compressive, racking and cyclic loading. Also, results showed SIP walls have a greater ability to dissipate energy under racking and cyclic loading that the stud wall system. Therefore, SIP walls can be used so efficient in seismic zones. Based on cyclic lateral load test results, the values of ductility-related force modification factor (Rd) for stud wall, short SIP wall and long SIP wall were calculated as 8%, 22% and 14% lower than the NBCC required value for anchored wall (Rd = 3.0), respectively. In addition cyclic lateral load test results showed that the values of over-strength-related force modification factor (Ro) for stud wall, short SIP wall and long SIP wall were observed to be 17%, 20% and 14% higher than the recommended value of NBCC (Ro = 1.7) for anchored wall, respectively. So, it is concluded that the over-strength factor indicates a confident reserve of resistance in interconnected wall segments.

Prediction of Tread Pattern Wear by an Explicit Finite Element Model3

2007 ◽  
Vol 35 (4) ◽  
pp. 276-299 ◽  
Author(s):  
J. C. Cho ◽  
B. C. Jung
Keyword(s):  
Finite Element ◽  
Wear Rate ◽  
Tangential Stress ◽  
Rate Equation ◽  
Constitutive Equations ◽  
Slip Velocity ◽  
Test Results ◽  
Explicit Finite Element ◽  
Driving Condition ◽  
Driving Conditions

Abstract Tread pattern wear is predicted by using an explicit finite element model (FEM) and compared with the indoor drum test results under a set of actual driving conditions. One pattern is used to determine the wear rate equation, which is composed of slip velocity and tangential stress under a single driving condition. Two other patterns with the same size (225/45ZR17) and profile are used to be simulated and compared with the indoor wear test results under the actual driving conditions. As a study on the rubber wear rate equation, trial wear rates are assumed by several constitutive equations and each trial wear rate is integrated along time to yield the total accumulated wear under a selected single cornering condition. The trial constitutive equations are defined by independently varying each exponent of slip velocity and tangential stress. The integrated results are compared with the indoor test results, and the best matching constitutive equation for wear is selected for the following wear simulation of two other patterns under actual driving conditions. Tens of thousands of driving conditions of a tire are categorized into a small number of simplified conditions by a suggested simplification procedure which considers the driving condition frequency and weighting function. Both of these simplified conditions and the original actual conditions are tested on the indoor drum test machines. The two results can be regarded to be in good agreement if the deviation that exists in the data is mainly due to the difference in the test velocity. Therefore, the simplification procedure is justified. By applying the selected wear rate equation and the simplified driving conditions to the explicit FEM simulation, the simulated wear results for the two patterns show good match with the actual indoor wear results.

scholarly journals Theoretical analysis and experimental research on multi-layer elastic damping track structure

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199497
Author(s):  
Guanghui Xu ◽  
Shengkai Su ◽  
Anbin Wang ◽  
Ruolin Hu
Keyword(s):  
Finite Element ◽  
Analytical Solution ◽  
Finite Element Simulation ◽  
Reaction Force ◽  
Vibration Reduction ◽  
Vertical Direction ◽  
Propagation Path ◽  
Track Structure ◽  
Test Results ◽  
Element Simulation

The increase of axle load and train speed would cause intense wheelrail interactions, and lead to potential vibration related problems in train operation. For the low-frequency vibration reduction of a track system, a multi-layer track structure was proposed and analyzed theoretically and experimentally. Firstly, the analytical solution was derived theoretically, and followed by a parametric analysis to verify the vibration reduction performance. Then, a finite element simulation is carried out to highlight the influence of the tuned slab damper. Finally, the vibration and noise tests are performed to verify the results of the analytical solution and finite element simulation. As the finite element simulation indicates, after installation of the tuned slab damper, the peak reaction force of the foundation can be reduced by 60%, and the peak value of the vertical vibration acceleration would decrease by 50%. The vibration test results show that the insertion losses for the total vibration levels are 13.3 dB in the vertical direction and 21.7 dB in the transverse direction. The noise test results show that the data of each measurement point is smoother and smaller, and the noise in the generating position and propagation path can be reduced by 1.9 dB–5.5 dB.

scholarly journals Stiffness Estimation and Equivalence of Boundary Conditions in FEM Models

2021 ◽  
Vol 11 (4) ◽  
pp. 1482
Author(s):  
Róbert Huňady ◽  
Pavol Lengvarský ◽  
Peter Pavelka ◽  
Adam Kaľavský ◽  
Jakub Mlotek
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Boundary Conditions ◽  
Model Updating ◽  
Element Model ◽  
Computational Time ◽  
Stiffness Coefficients ◽  
First Case ◽  
Numerical Approaches

The paper deals with methods of equivalence of boundary conditions in finite element models that are based on finite element model updating technique. The proposed methods are based on the determination of the stiffness parameters in the section plate or region, where the boundary condition or the removed part of the model is replaced by the bushing connector. Two methods for determining its elastic properties are described. In the first case, the stiffness coefficients are determined by a series of static finite element analyses that are used to obtain the response of the removed part to the six basic types of loads. The second method is a combination of experimental and numerical approaches. The natural frequencies obtained by the measurement are used in finite element (FE) optimization, in which the response of the model is tuned by changing the stiffness coefficients of the bushing. Both methods provide a good estimate of the stiffness at the region where the model is replaced by an equivalent boundary condition. This increases the accuracy of the numerical model and also saves computational time and capacity due to element reduction.

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