Finite Element Study of Double-Gasket Bolted Joint Connection for Different Gaskets and Bolt Torques

2017 ◽  
Author(s):  
Reza Ghafouri-Azar ◽  
Rosha Banan ◽  
Miodrag (Mike) Stojakovic
Keyword(s):  
Finite Element ◽  
Bolted Joints ◽  
Analysis Tool ◽  
Fe Model ◽  
Fe Modeling ◽  
Bolted Joint ◽  
Modeling And Analysis ◽  
Joint Connection ◽  
Size Type ◽  
The Right

In order to understand the behavior of bolted joints and select a right size, type and gasket load combination, a detailed analysis tool is very helpful. However, the modeling and analysis of a bolted joint connection is a complicated, complex process; particularly if multiple parts are considered in the Finite Element (FE) modeling. Analysis results are often sensitive to bolt pre-torque, gasket type, gasket thickness and other challenges of Finite Element (FE) modeling. In addition, often credible and reliable gasket deflection-load data are not readily available. The bolted joint under study was a double-gasket joint with inner gasket leakoff. The joint has leaked on several occasions, sometimes after several years of service due to warmup/cooldown cycling and sometimes immediately after installation and pressurization. A 3-D FE model was developed for assembly of tubesheet, bolt, two inner and outer gaskets, and vessel cover. Different cases were studied by changing gasket load-deflections for different gasket materials, gasket thicknesses and bolt loads. The outcome of the analyses was used to predict the behavior of bolted joints and understand the root cause of leakage. The results provided guidance for choosing the right combination of bolt pre-torque and gasket type.

Representation of bolted joints in a structure using finite element modelling and model updating

2020 ◽  
Vol 14 (3) ◽  
pp. 7141-7151 ◽  
Author(s):  
R. Omar ◽  
M. N. Abdul Rani ◽  
M. A. Yunus
Keyword(s):  
Finite Element ◽  
Dynamic Behaviour ◽  
Model Updating ◽  
Complex Structure ◽  
Bolted Joints ◽  
Model Parameters ◽  
Fe Model ◽  
Bolted Joint ◽  
Fe Modelling ◽  
Joint Structure

Efficient and accurate finite element (FE) modelling of bolted joints is essential for increasing confidence in the investigation of structural vibrations. However, modelling of bolted joints for the investigation is often found to be very challenging. This paper proposes an appropriate FE representation of bolted joints for the prediction of the dynamic behaviour of a bolted joint structure. Two different FE models of the bolted joint structure with two different FE element connectors, which are CBEAM and CBUSH, representing the bolted joints are developed. Modal updating is used to correlate the two FE models with the experimental model. The dynamic behaviour of the two FE models is compared with experimental modal analysis to evaluate and determine the most appropriate FE model of the bolted joint structure. The comparison reveals that the CBUSH element connectors based FE model has a greater capability in representing the bolted joints with 86 percent accuracy and greater efficiency in updating the model parameters. The proposed modelling technique will be useful in the modelling of a complex structure with a large number of bolted joints.

Accurate Evaluation of Bolt and Clamped Members Stiffnesses Of Bolted Joints

2021 ◽  
Author(s):  
Rashique Iftekhar Rousseau ◽  
Abdel-Hakim Bouzid ◽  
Zijian Zhao
Keyword(s):  
Finite Element ◽  
Joint Stiffness ◽  
Element Model ◽  
Fe Analysis ◽  
Bolted Joints ◽  
Analytical Models ◽  
Fe Modeling ◽  
Bolted Joint ◽  
A New Technique ◽  
External Loads

Abstract The axial stiffnesses of the bolt and clamped members of bolted joints are of great importance when considering their integrity and capacity to withstand external loads and resist relaxation due to creep. There are many techniques to calculate the stiffnesses of the joint elements using finite element (FE) modeling, but most of them are based on the displacement of nodes that are selected arbitrarily; therefore, leading to inaccurate values of joint stiffness. This work suggests a new method to estimate the stiffnesses of the bolt and clamped members using FE analysis and compares the results with the FE methods developed earlier and also with the existing analytical models. A new methodology including an axisymmetric finite element model of the bolted joint is proposed in which the bolts of different sizes ranging from M6 to M36 are considered for the analysis to generalize the proposed approach. The equivalent bolt length that includes the contribution of the thickness of the bolt head and the bolt nominal diameter to the bolt stiffness is carefully investigated. An equivalent bolt length that accounts for the flexibility of the bolt head is proposed in the calculation of the bolt stiffness and a new technique to accurately determine the stiffness of clamped members are detailed.

Parametric modeling and updating for bolted joints of aeroengine casings

2016 ◽  
Vol 230 (16) ◽  
pp. 2940-2951 ◽  
Author(s):  
Xue Zhai ◽  
Cheng-Wei Fei ◽  
Jian-Jun Wang ◽  
Xing-Yu Yao
Keyword(s):  
Thin Layer ◽  
Model Updating ◽  
Parametric Modeling ◽  
Bolted Joints ◽  
Maximum Relative Error ◽  
Fe Model ◽  
Fe Modeling ◽  
Bolted Joint ◽  
Static Stiffness ◽  
Fe Model Updating

To establish accurate finite element (FE) model of bolted joint structures of aeroengine stator system (casings), this work implements the parametric FE modeling and updating of bolted joints of aeroengine stator system with multi-characteristic responses (multi-object). Firstly, the parametric FE modeling approach of bolted joint structure was developed based on the thin layer element method. And then the FE model updating thought of aeroengine stator system was developed based on the probabilistic analysis method. Finally, the parametric modeling and updating of the bolted joints of aeroengine stator system with multi-characteristic responses was completed by the optimization iteration calculation of objective function based on the proposed methods and the static stiffness testing data. Through the parametric modeling of bolted joint structures based on the thin layer method, the complexity of FE model of aeroengine casings with many bolted joint structures is reduced. As shown in the FE model updating of casings with multi-characteristic responses analysis, the static stiffness from the updated model are very close to the test data, in which the maximum relative error decreases to 3.9% from 30.52% and the others are less than 3%, so that the design precision of aeroengine stator system with the many and wide variety of bolted joints gets a great improvement. Moreover, the proposed methods of parametric modeling and model updating for multi-characteristic responses are validated to be effective in the simulation and equivalent of the mechanical characteristics of bolted joints in complex systems like aeroengine stator system.

Finite Element Modeling of Self-Loosening of Bolted Joints

2004 ◽  
Author(s):  
Ming Zhang ◽  
Yanyao Jiang ◽  
Chu-Hwa Lee
Keyword(s):  
Finite Element ◽  
Contact Pressure ◽  
Bending Moment ◽  
Shear Loading ◽  
Transverse Load ◽  
Fe Model ◽  
Bolted Joint ◽  
Cyclic Bending ◽  
Second Stage ◽  
Cyclic Bending Moment

A three-dimensional finite element (FE) model with the consideration of the helix angle of the threads was developed to simulate the second stage self-loosening of a bolted joint. The second stage self-loosening refers to the graduate reduction in clamping force due to the back-off of the nut. The simulations were conducted for two plates jointed by a bolt and a nut and the joint was subjected to transverse or shear loading. An M12×1.75 bolt was used. The application of the preload was simulated by using an orthogonal temperature expansion method. FE simulations were conducted for several loading conditions with different preloads and relative displacements between the two clamped plates. It was found that due to the application of the cyclic transverse load, micro-slip occurred between the contacting surfaces of the engaged threads of the bolt and the nut. In addition, a cyclic bending moment was introduced on the bolted joint. The cyclic bending moment resulted in an oscillation of the contact pressure on the contacting surfaces of the engaged threads. The micro-slip between the engaged threads and the variation of the contact pressure were identified to be the major mechanisms responsible for the self-loosening of a bolted joint. Simplified finite element models were developed that confirmed the mechanisms discovered. The major self-loosening behavior of a bolted joint can be properly reproduced with the FE model developed. The results obtained agree quantitatively with the experimental observations.

Multidirection Validation of a Finite Element 50th Percentile Male Hybrid III Anthropomorphic Test Device for Spaceflight Applications

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Derek A. Jones ◽  
James P. Gaewsky ◽  
Mona Saffarzadeh ◽  
Jacob B. Putnam ◽  
Ashley A. Weaver ◽  
...  
Keyword(s):  
Finite Element ◽  
Injury Risk ◽  
Fe Model ◽  
Fe Modeling ◽  
Test Device ◽  
Qualitative And Quantitative ◽  
Hybrid Iii ◽  
Physical Tests ◽  
Quantitative Results ◽  
Male Hybrid

The use of anthropomorphic test devices (ATDs) for calculating injury risk of occupants in spaceflight scenarios is crucial for ensuring the safety of crewmembers. Finite element (FE) modeling of ATDs reduces cost and time in the design process. The objective of this study was to validate a Hybrid III ATD FE model using a multidirection test matrix for future spaceflight configurations. Twenty-five Hybrid III physical tests were simulated using a 50th percentile male Hybrid III FE model. The sled acceleration pulses were approximately half-sine shaped, and can be described as a combination of peak acceleration and time to reach peak (rise time). The range of peak accelerations was 10–20 G, and the rise times were 30–110 ms. Test directions were frontal (−GX), rear (GX), vertical (GZ), and lateral (GY). Simulation responses were compared to physical tests using the correlation and analysis (CORA) method. Correlations were very good to excellent and the order of best average response by direction was −GX (0.916±0.054), GZ (0.841±0.117), GX (0.792±0.145), and finally GY (0.775±0.078). Qualitative and quantitative results demonstrated the model replicated the physical ATD well and can be used for future spaceflight configuration modeling and simulation.

scholarly journals Nonlinear Axial Stiffness Characteristics of Axisymmetric Bolted Joints

1990 ◽  
Vol 112 (3) ◽  
pp. 442-449 ◽  
Author(s):  
I. R. Grosse ◽  
L. D. Mitchell
Keyword(s):  
Finite Element ◽  
Linear Theory ◽  
Design Theory ◽  
Joint Stiffness ◽  
Bolted Joints ◽  
Axial Stiffness ◽  
Outer Diameter ◽  
Bolted Joint ◽  
Element Analysis ◽  
Stiffness Characteristics

A critical assessment of the current design theory for bolted joints which is based on a linear, one-dimensional stiffness analysis is presented. A detailed nonlinear finite element analysis of a bolted joint conforming to ANSI standards was performed. The finite element results revealed that the joint stiffness is highly dependent on the magnitude of the applied load. The joint stiffness changes continuously from extremely high for small applied loads to the bolt stiffness during large applied loads, contrary to the constant joint stiffness of the linear theory. The linear theory is shown to be inadequate in characterizing the joint stiffness. The significance of the results in terms of the failure of bolted joints is discussed. A number of sensitivity studies were carried out to assess the effect of various parameters on the axial joint stiffness. The results revealed that bending and rotation of the joint members, interfacial friction, and the bolt/nut threading significantly influence the axial stiffness characteristics of the bolted joint. The two-dimensional, axisymmetric finite element model includes bilinear gap elements to model the interfaces. Special orthotropic elements were used to model the bolt/nut thread interaction. A free-body-diagram approach was taken by applying loads to the outer diameter of the joint model which correspond to internal, uniformly distributed line-shear and line-moment loads in the joint. A number of convergence studies were performed to validate the solution.

Automotive Glass Exciter Technology for Acoustic Application

2014 ◽  
Author(s):  
Babak Ebrahimi ◽  
Amir Khajepour ◽  
Todd Deaville
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Experimental Studies ◽  
Element Model ◽  
Fe Model ◽  
Component Level ◽  
Modeling And Analysis ◽  
Electric Actuator ◽  
Conventional Systems ◽  
Fine Tune

This paper discusses the modeling and analysis of a novel audio subwoofer system for automotive applications using the automobile windshield glass. The use of a piezo-electric actuator coupled with a mechanical amplifier linked to a large glass panel provides a highly efficient method of producing sound. The proposed subwoofer system has the advantage over existing conventional systems of not only reducing the weight of the automobile, but also a significant power savings resulting in an increase of expected fuel economy. Among various design challenges, the glass-sealing design is of huge importance, as it affects the system dynamic response and so the output sound characteristics. The main goal in this manuscript is to evaluate different glass-sealing design configurations by providing a comprehensive Finite Element model of the system. To do so, a comprehensive, yet simplified FE model is developed, and experimental studies are performed in the component level to fine-tune and verify the model. Harmonic response of the system for each sealing configuration design is obtained in the frequency range of 0–200 Hz, and the results are compared and discussed. The finite element model is also beneficial in preliminary design of other components as well as the exciter placement, and predicting the performance of the overall system.

Effect of Bolted Joints on Shock Propagation Across Structures Under Medium Impact Loading

2019 ◽  
Author(s):  
Pouya Shojaei ◽  
Mohamed Trabia ◽  
Brendan O’Toole
Keyword(s):  
Impact Loading ◽  
Shear Failure ◽  
Bolted Joints ◽  
Shock Propagation ◽  
Computational Techniques ◽  
Fe Model ◽  
Bolted Joint ◽  
Acceleration Signal ◽  
Shock Impact ◽  
Static Conditions

Abstract A bolted joint is one of the most common fastening techniques. While the behavior of bolted joints under static or quasi-static conditions is well documented, their behavior under shock/impact loading is not well-understood. In many applications, where a bolted joint connects a sensitive component to the rest of a structure, it is important to interpret shock propagation through the bolted joints. This problem is further complicated owing to the fact that a bolted joint exhibits multiple types of nonlinearities, due to the interaction between the bolts and clamped parts, thread friction between the shank and nut, pre-tension, damping characteristics, and interference with the hole. This study was focused on developing computational techniques for understanding shock propagation through a bolted joint. As a case study, the behavior of a bolted joint within a two-component cylindrical structure subjected to impact loading was considered. A finite element (FE) model of the fixture was developed. Two different approaches were considered. The first one modeled the bolt assembly as one part. The second model had the bolt and nut as separate parts. In this model, the tie contact between the bolt shank and the nut was defined using a shear failure criterion. Both models included bolt pre-tension. The two models were compared based on energy balance, acceleration signal, and displacement at the base of the fixture. The results indicated that the model with the separate bolt and nut resulted in a more realistic performance.

Study of bolted joint axial stiffness using finite element analyses, experimental tests, and analytical calculations

2020 ◽  
Vol 234 (23) ◽  
pp. 4671-4681
Author(s):  
Raphael Calazans Cardoso ◽  
Brenno Lima Nascimento ◽  
Felipe de Freitas Thompson ◽  
Sandro Griza
Keyword(s):  
Finite Element ◽  
Analytical Method ◽  
High Reliability ◽  
Experimental Tests ◽  
Bolted Joints ◽  
Axial Stiffness ◽  
Bolted Joint ◽  
Finite Element Analyses ◽  
Load Distributions ◽  
Reliable Design

The bolted joints sizing procedures shall adequately match the conditions imposed on the joint in service, to ensure high reliability designs. Therefore, this study aims to analyze the load distributions on the bolt when applying external load on bolted joints. Finite element and extensometry analyses as well as analytical calculations were performed in order to compare the magnitude of the joint overall stiffness, with respect to several available theories. The results acquired through the analytical method prescribed in the VDI 2230 standard as well as the finite element and extensometry analyses obtained great accordance. These results indicate that VDI 2230 standard adequately represents the mechanical behavior of the joint and should be used as a guideline for the reliable design of bolted joints subjected to the loading conditions of the present paper.

Nonlinear Behavior of Preloaded Bolted Joints Under a Cyclic Separating Load

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Xianjie Yang ◽  
Sayed A. Nassar ◽  
Zhijun Wu ◽  
Aidong Meng
Keyword(s):  
Finite Element ◽  
Deformation Behavior ◽  
Nonlinear Behavior ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Element Analysis ◽  
Linear Elastic ◽  
Plastic Deformation Behavior ◽  
Service Load ◽  
Joint Material

The nonlinear plastic deformation behavior of a clamped bolted joint model under a separating service load is investigated using analytical, finite element, and experimental techniques. An elastic-plastic model is used for the bolt material while the joint material remains in the linear elastic range. Both the analytical and finite element analysis (FEA) models investigate the variation in the tension of a preloaded bolt due to a separating service load that acts with an offset from the bolt center. Experimental verification is provided for both the analytical and finite element results on the bolt tension variation, clamp load variation and the clamp load loss caused by the incremental plastic bolt elongation under cyclic separating force.

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