Measurement of Bolt Clamping Forces by Electromagnetic Vibration Method Without Disassembling Bolted Joints

2006 ◽  
Author(s):  
Toshimichi Fukuoka ◽  
Nobukuni Sugano
Keyword(s):  
Contact Pressure ◽  
Experimental Studies ◽  
Service Condition ◽  
Point Of View ◽  
Bolted Joints ◽  
Joint Interface ◽  
Bolted Joint ◽  
Plate Interface ◽  
Vibration Method ◽  
Electromagnetic Vibration

The integrity and safety of a bolted joint can be greatly guaranteed by applying and maintaining an appropriate amount of bolt preloads. However, the variation of bolt preloads inevitably occurs in the service condition due to various reasons, even if the initial bolt preloads are properly applied. Accordingly, the monitoring of bolt forces in the service condition is significantly important. From the practical point of view, it is preferably conducted without disassembling the objective bolted joint. In this paper, Electromagnetic Vibration Method is introduced for monitoring the variation of bolt preloads in the service condition, and its performance is examined by experiments using bolted joints with various geometric configurations. Electromagnetic Vibration Method estimates the magnitude of bolt preload by measuring the resonant frequencies of the bolted joint, which vary in accordance with the contact pressure of the joint interface. From the experimental studies, Electromagnetic Vibration Method was found to be effective to evaluate the bolt force with a reasonable accuracy, except for the bolted joint whose plate interface being under very high contact pressure.

scholarly journals Relaxation of contact pressure and self-loosening in dynamic bolted joints

2016 ◽  
Vol 231 (18) ◽  
pp. 3462-3475 ◽  
Author(s):  
JT Stephen ◽  
MB Marshall ◽  
R Lewis
Keyword(s):  
Contact Pressure ◽  
Early Stage ◽  
Shear Loading ◽  
Bolted Joints ◽  
Joint Interface ◽  
Shear Load ◽  
Bolted Joint ◽  
Cyclic Shear ◽  
Constant Shear ◽  
Additional Constant

Bolted joints are widely used in a variety of engineering applications where they are dynamically loaded with frequencies of vibration spread over a wide spectrum with the same general effects. When under dynamic loading, bolted joints can become loose due to a loss in clamping pressure in the joints. This vibrational loosening sometimes can cause serious problems, and in some cases can lead to fatal consequences if it remains undetected. Non-intrusive ultrasonic and image processing techniques were simultaneously used to investigate the relaxation of contact pressure and loosening of bolted joints subjected to cyclic shear loading. Three critical areas, the contact interface of the bolted component, the bolt length and the rotation of the bolt head, were monitored during loosening of the joints. The results show that loosening of bolted joints can be grouped into three stages: very rapid, rapid, and gradual loosening. The earliest stage of the loosening of bolted joints is characterised by cyclic strain ratcheting–loosening of the bolted joint during vibration without rotation of the bolt head. The higher the rate of relaxation at this early stage, the lower is the resistance of the bolted joint to vibration-induced loosening. Both the dynamic shear load and an additional constant shear load in another direction were observed to affect the rate of loosening, and at this early stage, a rise in the magnitude of the additional constant shear load increases the rate of loosening. Furthermore, the contact pressure distribution affects the rate of loosening at the bolted joint interface, as loosening increases away from area of high contact pressure.

scholarly journals Comparative Studies of the Seatings of Propulsion Plants and Auxiliary Machinery on Chocks Made of Metal and Cast of Resin Part I. Mounting on Steel Chocks

2019 ◽  
Vol 26 (4) ◽  
pp. 142-148
Author(s):  
Paweł Grudziński ◽  
Konrad Konowalski
Keyword(s):  
Comparative Analysis ◽  
Scientific Explanation ◽  
Experimental Studies ◽  
Point Of View ◽  
Bolted Joints ◽  
Engineering Practice ◽  
Bolted Joint ◽  
Science And Engineering ◽  
Analysis And Evaluation ◽  
Resin Part

Abstract This paper presents a description and the results of experimental studies of the deformation, friction and structural damping occurring in foundation bolted joints of propulsion plant components and auxiliary machinery that is rigidly mounted on sea-going ships. The rigid mounting of these devices to the ships’ structural foundations can be implemented in a traditional way, i.e. on chocks made of metal (usually of steel), or in a modern way, i.e. on chocks cast of resin, specially designed for this purpose. The main goal of this study is to perform a comparative analysis of these two solutions and to give a scientific explanation for why chocks cast of resin perform better in machinery seatings than the steel chocks traditionally used for this purpose. The paper consists of two parts. Part I presents the details of the rigid mountings of machinery to the foundations, and contains the results of experimental studies performed on a model of a foundation bolted joint with a traditional steel chock. Part II contains the results of similar studies carried out for a model of a bolted joint with a modern chock cast of resin. Next, a comparative analysis and evaluation of the results obtained for both investigated bolted joints was carried out, and conclusions were formulated to highlight important aspects of the problem from the point of view of science and engineering practice.

An investigation into contact pressure distribution in bolted joints

2014 ◽  
Vol 228 (18) ◽  
pp. 3405-3418 ◽  
Author(s):  
JT Stephen ◽  
MB Marshall ◽  
R Lewis
Keyword(s):  
Pressure Distribution ◽  
Contact Pressure ◽  
Applied Load ◽  
Plate Thickness ◽  
Operating Conditions ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Contact Pressure Distribution ◽  
Engineering Structures ◽  
Peak Value

Bolted joints are widely used in modern engineering structures and machine designs due to their low cost and reliability when correctly selected. Their integrity depends on quantitative representation of the contact pressure distribution at the interface during design. Because of the difficulty in reaching and assessing clamped interfaces with traditional experimental methods, presently bolted joint design and evaluation is based on theoretical analysis, with assumptions to quantify pressure distribution at the clamped interface, which may not represent their true operating conditions. The present work utilises a non-intrusive ultrasonic technique to investigate and quantify the pressure distribution in bolted joints. The effect of variation in plate thickness on the contact pressure distribution at bolted interfaces under varying axial loads is investigated. While it was observed that the contact pressure at the interface increases as the applied load increases, the distance from the edge of the bolt hole at which the distribution becomes stable is independent of the applied load on the bolted joint. However, the contact pressure distribution was observed to vary with the plate thickness. Although the variation in the peak value of the average contact pressure distribution in bolted joints does not depend on the plate thickness, the distance from the edge of bolt hole at which the value of the distribution becomes stable increases as the plate thickness is increased. It was also observed that the edge of the bolt head affected the position of the peak value of the contact pressure distribution at the interface, though its effect was dependent on plate thickness. Furthermore, a model based on a Weibull distribution has been proposed to fit the experimental data and a good correlation was observed.

Finite Element Simulation in the Dynamics Calculation of Bolted-Joint Interface

2012 ◽  
Vol 215-216 ◽  
pp. 1009-1012
Author(s):  
Yan Ting Ai ◽  
Yan Bai ◽  
Xue Zhai ◽  
Dan Zhao
Keyword(s):  
Experimental Data ◽  
Material Properties ◽  
Interface Layer ◽  
Bolted Joints ◽  
Joint Interface ◽  
Bolted Joint ◽  
Linear Dynamic ◽  
Element Simulation ◽  
Aero Engine ◽  
Dynamics Calculation

Many components in modern mechanical structure are connected with bolts, and the behaviour of joints significantly affects the dynamic response of these structures. Based on the software of MSC. patran, firstly, a linear dynamic model for bolted joints and interface is developed. The joint interface is modeled using a technology of interface layer element(ILE) and multi-point constrains(MPC) technique. And then, using the MATLAB language, the properties of ILE material are optimized to simulate the bolted-joint interface stiffness. The material properties parameters are identified by using experimental data. This work takes aero-engine case model as an example, researching its model analysis under different pre-stress conditions to check the method and provide insight on how to model the joint interface in the dynamics calculation of bolted structure.

scholarly journals Comparative Studies of the Seatings of Propulsion Plantsand Auxiliary Machinery on Chocks Made of Metal and Cast from Resin Part II. Mounting on Cast Resin Chocks

2020 ◽  
Vol 27 (1) ◽  
pp. 126-133
Author(s):  
Paweł Grudziński ◽  
Konrad Konowalski
Keyword(s):  
Comparative Analysis ◽  
Comparative Studies ◽  
Research Work ◽  
Experimental Studies ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Structural Damping ◽  
Relevant Research ◽  
Resin Part ◽  
Plant Components

AbstractThis article is Part II of the paper containing a description and results of the experimental studies of the deformations, friction processes and structural damping that occur in the foundation bolted joints of propulsion plant components and auxiliary machinery installed on sea-going ships. Part I of this research work presents an analysis of the rigid mountings of machines and devices to the foundations on steel or resin chocks, and explains the need to carry out relevant research in this area. It also presents the description and results of experimental studies carried out for a foundation bolted joint with a conventionally used steel chock. Part II (this article) contains a description and results of similar studies carried out for a foundation bolted joint with a modern chock – cast from epoxy resin compound (EPY), specially developed for this purpose. Then, a comparative analysis of the results obtained for both bolted joints in question was made and the foundation chocks of the poured-in-place resin compound were demonstrated to better fulfill their technical tasks than the steel chocks traditionally used for this purpose.

On the Use of Shape Memory Alloy Studs to Recover Load Loss in Bolted Joints

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Nazim Ould-Brahim ◽  
Abdel-Hakim Bouzid ◽  
Vladimir Brailovski
Keyword(s):  
Shape Memory ◽  
Analytical Model ◽  
Experimental Studies ◽  
Thermal Exposure ◽  
Element Model ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Creep Properties ◽  
Material Creep ◽  
Joint Assembly

Creep is an important factor that contributes to the clamp load loss and tightness failure of bolted joints with and without gaskets over time. Retightening of the joint can be expensive and time consuming; therefore, it is an undesirable solution. Currently, most efforts are put towards reducing load losses directly by tightening to yield, improving material creep properties, or making joint less rigid. An alternative solution of current interest is the use of bolts in shape memory alloys (SMAs). However, very few experimental studies are available, which demonstrate the feasibility of these alloys. The objective of this study is to explore the benefit of shape memory and superelasticity behavior of an SMA stud to recover load losses due to creep and thermal exposure of a gasket in a bolted-joint assembly. This paper explores several venues to investigate and model the thermomechanical behavior of a bolted joint with a nickel–titanium SMA stud. A stiffness-based analytical model which incorporates the Likhachev model of SMA is used as a representation of an experimental bolted-joint assembly. Based on this model, the rigidity of the experimental setup is optimized to make the best use of the SMA properties of the stud. This analytical model is compared with a finite element model, which also implements the Likhachev's material law. Finally, an experimental test bench with a relatively low stiffness representative of standard flanges is used, with and without gaskets to demonstrate the ability of the SMA stud to recover load losses due to gasket creep.

Factors Affecting Contact Pressure Distribution on Bolted Joint Interface

2016 ◽  
Vol 693 ◽  
pp. 126-133
Author(s):  
Jing Ping Liao ◽  
Ding Wen Yu ◽  
Ping Fa Feng
Keyword(s):  
Pressure Distribution ◽  
Contact Pressure ◽  
Contact Radius ◽  
Joint Interface ◽  
Bolted Joint ◽  
Contact Interface ◽  
Interface Pressure ◽  
Contact Pressure Distribution ◽  
Factors Affecting ◽  
Bolt Diameter

To investigate factors affecting contact interface pressure distribution in bolted joint, a parametric model was established by ANSYS APDL language in this paper. The contact pressure distribution on bolted joint interface was obtained through interpolating and revising contact interface forces. It is observed that the position of peak interface pressure is between the edge of bolt hole and the edge of bolt head. The contact pressure linearly changes with the bolt load while the distribution trend and radius remain unchanged. When the total thickness of clamped members is fixed, the contact pressure distribution varies from concentrated to uniform with the increasing member thickness ratio, and the maximum contact radius is reached while the member thickness is equal. When one clamped member thickness is fixed, increasing the other’s thickness can also reduce the contact pressure concentration, but the effect gradually weakens. Increasing bolt diameter can slightly increase the absolute contact radius but decrease the normalized contact radius. The inclusion of a washer under the nut can slightly promote interface clamping.

Masonry: the brittle or plastic material?

2019 ◽  
pp. 22-28
Keyword(s):  
Plastic Material ◽  
Experimental Studies ◽  
Point Of View ◽  
Plastic Properties ◽  
Plastic Deformations ◽  
Base Materials ◽  
Stress States ◽  
Creep Deformations ◽  
Structural Point

The results of experimental studies of masonry on the action of dynamic and static (short-term and long-term) loads are presented. The possibility of plastic deformations in the masonry is analyzed for different types of force effects. The falsity of the proposed approach to the estimation of the coefficient of plasticity of masonry, taking into account the ratio of elastic and total deformations of the masonry is noted. The study of the works of Soviet scientists revealed that the masonry under the action of seismic loads refers to brittle materials in the complete absence of plastic properties in it in the process of instantaneous application of forces. For the cases of uniaxial and plane stress states of the masonry, data on the coefficient of plasticity obtained from the experiment are presented. On the basis of experimental studies the influence of the strength of the so-called base materials (brick, mortar) on the bearing capacity of the masonry, regardless of the nature of the application of forces and the type of its stress state, is noted. The analysis of works of prof. S. V. Polyakov makes it possible to draw a conclusion that at the long application of the load, characteristic for the masonry are not plastic deformations, but creep deformations. It is shown that the proposals of some authors on the need to reduce the level of adhesion of the mortar to the brick for the masonry erected in earthquake-prone regions in order to improve its plastic properties are erroneous both from the structural point of view and from the point of view of ensuring the seismic resistance of structures. It is noted that the proposal to assess the plasticity of the masonry of ceramic brick walls and large-format ceramic stone with a voidness of more than 20% is incorrect, and does not meet the work of the masonry of hollow material. On the basis of the analysis of a large number of research works it is concluded about the fragile work of masonry.

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.

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