Novel Formulation of Bolt Elastic Interaction in Gasketed Joints

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Sayed A. Nassar ◽  
Xianjie Yang
Keyword(s):  
Modulus Of Elasticity ◽  
Load Distribution ◽  
Test Procedure ◽  
Interaction Model ◽  
Elastic Interaction ◽  
Numerical Results ◽  
Experimental Results ◽  
Experimental Setup ◽  
Initial Assembly

Novel formulation was proposed for studying bolt elastic interaction during the tightening of a group of fasteners in flat faced gasketed joints. The model was used for developing tightening strategies that would achieve a more uniform clamp load in the flange at initial assembly. Clamp load distribution is investigated for various tightening sequences and values for the gasket modulus of elasticity, gasket thickness, and grip length. An experimental setup and test procedure were developed to verify the numerical results produced by the elastic interaction model. Analytical and experimental results were presented and discussed.

A Novel Formulation of Elastic Interaction in Gasketed Bolted Joints

2007 ◽  
Author(s):  
Ali A. Alkelani ◽  
Sayed A. Nassar ◽  
Basil A. Housari
Keyword(s):  
Mathematical Model ◽  
Load Distribution ◽  
Elastic Interaction ◽  
Bolted Joints ◽  
Good Prediction ◽  
Proposed Model ◽  
Joint Tightening ◽  
The Mathematical Model ◽  
Bolt Spacing ◽  
Initial Assembly

A novel mathematical model is proposed for studying elastic interaction in gasketed bolted joints. The model predicts the tension changes in tightened bolts due to the subsequent tightening of other bolts in the joint. It also predicts the final clamp load distribution after the completion of joint tightening. The model is used to investigate the effect of various factors on the elastic interaction phenomenon; factors include the gasket thickness, bolt spacing, fastener preload level, and the tightening sequence of various bolts. Experimental verification is provided for the validation of the mathematical model. Experimental and analytical results are presented and discussed. The proposed model provides good prediction of the final clamp load in the joint. Moreover, the proposed model may be used to determine the level of initial bolt tension in each bolt that would be necessary to achieve the desired level of uniform clamp load in the joint at initial assembly.

Formulation of Elastic Interaction Between Bolts During the Tightening of Flat-Face Gasketed Joints

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Ali A. Alkelani ◽  
Sayed A. Nassar ◽  
Basil A. Housari
Keyword(s):  
Mathematical Model ◽  
Load Distribution ◽  
Elastic Interaction ◽  
Bolted Joints ◽  
Good Prediction ◽  
Proposed Model ◽  
Joint Tightening ◽  
The Mathematical Model ◽  
Bolt Spacing ◽  
Initial Assembly

A novel mathematical model is proposed for studying elastic interaction in gasketed bolted joints. The model predicts the tension changes in tightened bolts due to the subsequent tightening of other bolts in the joint. It also predicts the final clamp load distribution after the completion of joint tightening. The model is used to investigate the effect of various factors on the elastic interaction phenomenon; factors include the gasket thickness, bolt spacing, fastener preload level, and tightening sequence of various bolts. Experimental verification is provided for the validation of the mathematical model. Experimental and analytical results are presented and discussed. The proposed model provides a good prediction of the final clamp load in the joint. Moreover, the proposed model may be used to determine the level of initial bolt tension in each bolt that would be necessary to achieve the desired level of uniform clamp load in the joint at the initial assembly.

Simulation of a Free Standing Riser Model and Validation With Experimental Results

2014 ◽  
Author(s):  
Marcio Yamamoto ◽  
Sotaro Masanobu ◽  
Satoru Takano ◽  
Shigeo Kanada ◽  
Tomo Fujiwara ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Previous Experiment ◽  
Numerical Results ◽  
Experimental Results ◽  
Previous Article ◽  
Scale Model ◽  
Analysis Software ◽  
Free Standing ◽  
Reduced Scale

In this article, we present the numerical analysis of a Free Standing Riser. The numerical simulation was carried out using a commercial riser analysis software suit. The numerical model’s dimensions were the same of a 1/70 reduced scale model deployed in a previous experiment. The numerical results were compared with experimental results presented in a previous article [1]. Discussion about the model and limitations of the numerical analysis is included.

Load Distribution of Parallel Springs With Random Length and Stiffness

1987 ◽  
Vol 109 (4) ◽  
pp. 402-406 ◽  
Author(s):  
Go¨ran Gerbert ◽  
Jacques de Mare´
Keyword(s):  
Uniform Distribution ◽  
Load Distribution ◽  
Simple Formula ◽  
Mechanical Design ◽  
Numerical Results ◽  
Maximal Length ◽  
Major Influence ◽  
Length Variation ◽  
Spring Stiffness ◽  
Failure Risk

There are many applications in mechanical design where load distribution is modelled with parallel springs. Here random variation in spring length and spring stiffness is considered. Length variation is assumed to be the major influence and the case with uniform distribution is analyzed in detail. Small variations in spring stiffness are included. Numerical results are given. A simple formula is presented which gives the maximal length deviation as a function of the number of springs. The formula is based on a 10 percent failure risk which is a common number in practical mechanical design.

scholarly journals A Generalized Method for Flat Plates Impact Detection and Location

2013 ◽  
Vol 543 ◽  
pp. 171-175
Author(s):  
Jose Andrés Somolinos ◽  
Rafael Morales ◽  
Carlos Morón ◽  
Alfonso Garcia
Keyword(s):  
Signal Processing ◽  
Flat Plate ◽  
Acoustic Signal ◽  
Experimental Results ◽  
Piezoelectric Sensors ◽  
Experimental Setup ◽  
Flat Plates ◽  
Impact Detection ◽  
Timing Difference

In the last years, many analyses from acoustic signal processing have been used for different applications. In most cases, these sensor systems are based on the determination of times of flight for signals from every transducer. This paper presents a flat plate generalization method for impact detection and location over linear links or bars-based structures. The use of three piezoelectric sensors allow to achieve the position and impact time while the use of additional sensors lets cover a larger area of detection and avoid wrong timing difference measurements. An experimental setup and some experimental results are briefly presented.

On the Stresses in a Notched Strip

1952 ◽  
Vol 19 (2) ◽  
pp. 141-146
Author(s):  
Chih-Bing Ling
Keyword(s):  
Infinite System ◽  
Linear Equations ◽  
Numerical Results ◽  
Theoretical Solution ◽  
Experimental Results ◽  
System Of Linear Equations ◽  
Transverse Bending ◽  
Longitudinal Tension

Abstract In a previous paper by the author (1), a theoretical solution for a notched strip under longitudinal tension is given. The result demands the solution of an infinite system of linear equations. A considerable amount of labor is involved in solving such a system. It seems, however, that the labor can be diminished by adapting to the solution a process known as the promotion of rank. In this paper such a process is described and then applied to solve the problem of a notched strip under transverse bending. The solution of this problem seems also to be new. The numerical results obtained are compared graphically with the experimental results available.

scholarly journals Free Vibration Analysis of Fiber Metal Laminated Straight Beam

2018 ◽  
Vol 16 (1) ◽  
pp. 944-948 ◽  
Author(s):  
Sinan Maraş ◽  
Mustafa Yaman ◽  
Mehmet Fatih Şansveren ◽  
Sina Karimpour Reyhan
Keyword(s):  
Free Vibration ◽  
Vibration Analysis ◽  
High Performance ◽  
Free Vibration Analysis ◽  
Vibration Characteristics ◽  
Numerical Results ◽  
Experimental Results ◽  
Hybrid Structures ◽  
Straight Beam ◽  
Fiber Metal

AbstractIn recent years, studies on the development of new and advanced composite materials have been increasing. Among these new technological products, Fiber Metal Laminates (FML), and hybrid structures made of aluminium, carbon, glass or aramid fiber, are preferred especially in the aircraft industry due to their high performance. Therefore, free vibration analysis is necessary for the design process of such structures. In this study, the vibration characteristics of FML for clamped-free boundary conditions were investigated experimentally and numerically. Firstly, numerical results were obtained using Finite Element Method (FEM) and then these results were compared with the experimental results. It was seen that the numerical results were in good agreement with the experimental results. As the theoretical model was justified, the effects of various parameters such as number of layers, fiber orientations, and aluminium layer thickness on the in-plane vibration characteristics of the FML straight beam were analysed using FEM. Thus, most important parameters affecting the vibration characteristics of the hybrid structures were determined.

Application of Bolted Flange Joint Assembly Guidelines HPIS Z103 TR to ePTFE Sheet Gasket

2008 ◽  
Author(s):  
Hirokazu Tsuji ◽  
Yuuki Terui
Keyword(s):  
Relaxation Rate ◽  
Modulus Of Elasticity ◽  
Elastic Interaction ◽  
Flange Joint ◽  
Fiber Sheet ◽  
Force Reduction ◽  
Assembly Procedure ◽  
Bolted Flange ◽  
Application Scope ◽  
Joint Assembly

Bolt tightening guidelines HPIS Z 103 TR for flange joint assemblies have been developed to provide a simple and effective procedure to tighten flange joint bolts. This assembly procedure is applicable to compressed fiber sheet gaskets and spiral wound gaskets, but is not applicable to expanded PTFE (ePTFE) sheet gaskets for the reason that the ePTFE material has lower modulus of elasticity and higher creep/relaxation rate. In this study, expansion of the application scope of HPIS Z103 TR to ePTFE sheet gaskets is investigated. Tightening tests are conducted using flange joint specimens of JPI 4 inch and 6 inch, and all bolt forces and flange gaps are measured at each tightening step to check for uneven tightening. Uniformity of the bolt forces and flange gaps are comparable to those obtained by other types of gaskets or by tightening procedure ASME PCC-1. The influences of gasket relaxation and elastic interaction on the bolt forces are also demonstrated. As a result, flange joint assembly guidelines HPIS Z 103 TR can be considered applicable to the high-density ePTFE sheet gasket, although a post-tightening step of 1 or 2 passes is necessary to compensate for the bolt force reduction induced by gasket relaxation.

Numerical modeling of high velocity impact in sandwich panels with honeycomb core and composite skin including composite progressive damage model

2018 ◽  
Vol 22 (8) ◽  
pp. 2768-2795 ◽  
Author(s):  
Meysam Khodaei ◽  
Mojtaba Haghighi-Yazdi ◽  
Majid Safarabadi
Keyword(s):  
Numerical Model ◽  
Sandwich Panel ◽  
Material Model ◽  
Absorption Capacity ◽  
Numerical Results ◽  
Ballistic Impact ◽  
Experimental Results ◽  
Ballistic Limit ◽  
Honeycomb Core ◽  
Damage Initiation

In this paper, a numerical model is developed to simulate the ballistic impact of a projectile on a sandwich panel with honeycomb core and composite skin. To this end, a suitable material model for the aluminum honeycomb core is used taking the strain-rate dependent properties into account. To validate the ballistic impact of the projectile on the honeycomb core, numerical results are compared with the experimental results available in literature and ballistic limit velocities are predicted with good accuracy. Moreover, to achieve composite skin material model, a VUMAT subroutine including damage initiation based on Hashin’s seven failure criteria and damage evolution based on MLT approach modulus degradation is used. To validate the composite material model VUMAT subroutine, the ballistic limit velocities of the projectile impact on the composite laminates are predicted similar to the numerical results presented by other researchers. Next, the numerical model of the sandwich panel ballistic impact at different velocities is compared with the available experimental results in literature, and energy absorption capacity of the sandwich panel is predicted accurately. In addition, the numerical model simulated the sandwich panel damage mechanisms in different stages similar to empirical observations. Also, the composite skin damages are investigated based on different criteria damage contours.

The effects of grooved rubber blocks on stick–slip and wear behaviours

2018 ◽  
Vol 233 (11) ◽  
pp. 2939-2954 ◽  
Author(s):  
Xiao Cui Wang ◽  
Ji Liang Mo ◽  
Huajiang Ouyang ◽  
Xiao Dong Lu ◽  
Bo Huang ◽  
...  
Keyword(s):  
Relative Velocity ◽  
Surface Modifications ◽  
Experimental Results ◽  
Brake Disc ◽  
Experimental Setup ◽  
Brake Pad ◽  
Stick Slip ◽  
Elastic Rubber ◽  
Disc Configuration ◽  
Rubber Block

This work presents an experimental and theoretical combined study of the effects of the elastic rubber blocks with different surface modifications on the friction-induced stick–slip oscillation and wear of a brake pad sample in sliding contact with an automobile brake disc. The experiments are conducted on the customized experimental setup in a pad-on-disc configuration. The experimental results show that (1) the friction system with the plain rubber block still exhibits visible stick–slip oscillation, but the intensity of the stick–slip oscillation is reduced to a certain degree compared with the Original friction system (without rubber block); (2) the grooved rubber blocks display a better ability to reduce the stick–slip oscillation compared with the plain rubber block; (3) the rubber blocks with a vertical groove (perpendicular to the relative velocity) or a horizontal groove (parallel to the relative velocity) or a diagonal groove (45° inclined to the relative velocity) on their surfaces can suppress the stick–slip oscillation more effectively with various degrees of success. The experimental results also reveal the varying effects of the different rubber blocks on wear. To explain the experimental phenomenon reasonably, a theoretical analysis is conducted to investigate the effects of different rubber blocks on both stick–slip oscillation and wear using ABAQUS. Furthermore, the analysis of the contact pressure on the pad interfaces and the deformation of the rubber blocks are studied to provide a possible explanation of the experimental results.

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