scholarly journals Influence of Configuration Error in Bolted Joints on Detection Error of Clamp Force Detection Method

2021 ◽  
Vol 15 (4) ◽  
pp. 396-403
Author(s):  
Shinji Hashimura ◽  
Hisanori Sakai ◽  
Kai Kubota ◽  
Nozomi Ohmi ◽  
Takefumi Otsu ◽  
...  
Keyword(s):  
Tensile Force ◽  
Bolted Joints ◽  
Detection Accuracy ◽  
Bolted Joint ◽  
Detection Error ◽  
Bearing Surface ◽  
Force Detection ◽  
Clamp Force ◽  
Squareness Error ◽  
The Relationship

Clamp force errors in bolted joints often cause accidents in various mechanical structures. Therefore, the clamp force must be controlled accurately and maintained for securing the reliability of mechanical structures such as vehicles. However, the clamp force cannot be controlled easily during tightening. Moreover, it is difficult to detect the clamp force after tightening. We previously proposed a method to easily detect the clamp force of a bolted joint that has been tightened. In that method, the bolt thread protruding from the nut is pulled while the nut’s upper surface is supported. The relationship between tensile force and displacement at the pulling point where the tensile force is applied differs before and after the tensile force reaches the clamp force. The method detects the tensile force at the point, where the relationship changes, as the clamp force. In this study, we investigate the influence of squareness error on the bearing surface of the clamped part in a bolted joint on the detection error of the method using experiments and finite element (FE) analysis. The experimental results show that the squareness error has an influence on the detection accuracy. The average detection error in the experiments increases by approximately 10% with an increase in the squareness error. To understand the cause of this phenomenon, we investigate the effects of backlash between mating thread surfaces of bolts and nuts on the detection error. The results show that the error decreased because of the backlash. Consequently, it is assumed that the error is caused by the non-separation of the mating thread surfaces when the tensile force reached the clamp force. Furthermore, the FE analysis results show that the squareness error on the bearing surface of the clamped part has an influence of the squareness error on the detection accuracy. The results indicate that we should control the tolerance of squareness errors on the bearing surface of the clamped part when the clamp force detection method is applied to bolted joints.

Robustness of Detection Method for Clamp Force Against Configuration Error in Bolt/Nut Assemblies

2020 ◽  
Author(s):  
Shinji Hashimura ◽  
Kai Kubota ◽  
Nozomu Ohmi ◽  
Kyoichi Komatsu
Keyword(s):  
Detection Method ◽  
Tensile Force ◽  
Fe Analysis ◽  
Detection Accuracy ◽  
Bearing Surface ◽  
Clamp Force ◽  
Squareness Error ◽  
Before And After ◽  
The Relationship

Abstract Reliability of bolt/nut assemblies directly influences the quality of machines and structures. It is most important to control and maintain the clamp force of bolt/nut assemblies to secure reliability. However it is not easy to control the clamp force during tightening. And it is also difficult to detect the clamp force after tightening. In our previous study, we proposed a method to easily detect the clamp force of bolt/nut assemblies that have already been tightened. In the method, the bolt thread portion protruding from the nut is pulled while supporting the nut’s upper surface. The relationship between the tensile force and the displacement at the pulling point differs before and after the tensile force reaches the clamp force. The method can detect the tensile force at the point where the relationship changes as the clamp force. In this study, robustness of the detection method for the squareness error of the bearing surface of clamped parts has been investigated by FE analysis and experiments. The results of the FE analysis showed that the squareness error of the bolt bearing surface does not have an influence on the detection accuracy. The results indicate that the detection method has robustness for the squareness error of bolt bearing surfaces. Contrary to that, the experimental results show that the squareness error does have a clear influence on the detection accuracy. The averages of detection error in the experiments increased about 10% with an increase in squareness error. It is considered that the error was caused because the mating thread surfaces did not separate when the tensile force reached the clamp force.

A Combined Stress Model for the Elasto-Plastic Analysis of Clamp Loads in Bolted Joints Under a Cyclic Separating Force

2006 ◽  
Author(s):  
Sayed A. Nassar ◽  
Xianjie Yang
Keyword(s):  
Twist Angle ◽  
Bolted Joints ◽  
Stress Model ◽  
Bolted Joint ◽  
Combined Stress ◽  
New Approach ◽  
Permanent Set ◽  
Clamp Force ◽  
Service Load ◽  
The Relationship

In this paper, a nonlinear combined stress model is established for a typical bolted joint for the purpose of studying its behavior under a separating service load. The combined effect of axial and torsional stresses in the tightened threaded fastener is considered. A new approach for the analysis of the clamping force loss is proposed under different pre-tightening with different thread friction coefficient and different separating loading. The_nonlinear model is established based on the elasto-perfectly plasticity in order to describe the fastener behavior over the yielding of its material, and to determine the relationship between the axial bolt force and elongation under tightening and the separating loading with specific twist angle, and to predict the clamp force loss due to the permanent set in the fastener after the separating force has been removed. The nonlinear relationship between the bolt axial force and the bolt elongation depends on the initial twist angle and the tightening preload. Finally, the effects_of the fastener pre-tightening, the initial twist angle and the bolt and joint members' elastic properties on the amount of clamp load loss are investigated.

Elasto-Plastic Stress Analysis of the Characteristics for T-Flange Bolted Joints Under External Loading

2013 ◽  
Author(s):  
Yuya Omiya ◽  
Toshiyuki Sawa
Keyword(s):  
Stress Analysis ◽  
Tensile Load ◽  
Bending Moment ◽  
Bolted Joints ◽  
External Loading ◽  
Load Factor ◽  
Bolted Joint ◽  
Bearing Surface ◽  
Permanent Set ◽  
Bolt Preload

In designing bolted joints, it is necessary to know the contact stress distributions in bolted joints. Recently, high strength bolts have been used with a higher bolt preload. As the results, the permanent set occurs sometimes at the bearing surfaces of clamped parts in the bolted joint. In addition, when external loads such as tensile loads, transverse loads and bending moments are applied to the bolted joint, the permanent set can be extended at the bearing surfaces. As the permanent set increases, the reduction in the bolt preload increases. Thus, it is important to estimate the reduction in the bolt preload from the reliability stand point. However, no study on the permanent set at the bearing surface under the external loading taking into account the bending moment has been carried out. In this study, the stress distribution and the extension of the permanent set at the bearing surface of the T-flange bolted joint under the external tensile loading are examined using Finite Element Method (FEM), where two T-flanges are clamped with a hexagon bolt and a nut. Using the obtained results, an increment in the axial bolt force and the reduction in the bolt preload are estimated. For verification of the FEM stress analysis, the load factor of hexagon bolt was measured. The FEM results of the load factor (the ratio of the increment in the axial bolt force to the tensile load) and the axial bolt force are in a fairly good agreement with the experimental results.

An Experimental Investigation on Frictional Properties of Bolted Joints

2002 ◽  
Author(s):  
Yanyao Jiang ◽  
Ming Zhang ◽  
Tae-Won Park ◽  
Chu-Hwa Lee
Keyword(s):  
Experimental Investigation ◽  
Contact Area ◽  
Direct Determination ◽  
Organic Coating ◽  
Bolted Joints ◽  
Marginal Effect ◽  
Bolted Joint ◽  
Bearing Surface ◽  
Frictional Properties ◽  
Bearing Friction

By using an approach developed to determining the torque-tension relationship for bolted joints, frictional properties of several typical bolted joints were studied experimentally. The approach allows for the direct determination of the thread friction and the bearing friction between the nut and its bearing surface independently. Detailed studies were made on the influences of the size and shape of the hole, the use of a slot in a bolted joint, contact area and position, and other factors such as turning speed, coating, and the use of wax on the bearing surface. The contact area and position of the washer have a marginal effect on the bearing friction. The organic coating on the nuts reduces the bearing friction significantly. Nuts with organic coating over a washer with zinc finish provide the smallest and the most consistent bearing friction. Experiments on thread friction shows that prevailing torque nuts with distorted threads and nylon inserts provided trivial benefits for preventing “self-loosening” of the nut. Repeated tightening-loosening generally increases frictions in a bolted joint. It was noted that the data scatter of the experimental results of frictions in a bolted joint may overshadow the influence of size, speed, and contact positions. The results from the experimental investigation will help to better design bolted joints.

FEM Stress Analysis of the Characteristics of Bolted Joints Under External Loadings (In the Case Where Two Hollow Cylinders Are Clamped)

2011 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Kengo Kuwaki ◽  
Yukio Morozumi ◽  
Masahiko Okumura
Keyword(s):  
Stress Analysis ◽  
Theory Of Elasticity ◽  
Bolted Joints ◽  
External Loading ◽  
Load Factor ◽  
Bolted Joint ◽  
Bearing Surface ◽  
Permanent Set ◽  
Bolt Preload ◽  
Hollow Cylinders

In designing bolted joints, it is necessary to know the stress distributions in bolted joints. Recently, high strength bolts have been used with a higher bolt preload. As the results, the permanent set occurs sometimes at the bearing surfaces of clamped parts in a bolted joint. In addition, when an external load is applied to the bolted joint, the permanent set can be extended at the bearing surfaces. As the permanent set increases, the reduction in the bolt preload increases. Thus, it is important to estimate the reduction in the bolt preload from the reliability stand point. However, no study on the permanent set at the bearing surface under the external loading has been carried out. In this study, the stress distribution and the extension of the permanent set at the bearing surface of the bolted joint under the external tensile loading are examined using finite element Method (FEM), where two hollow cylinders are clamped with a hexagon bolt and a nut. The spring constants for the hexagon bolt and the clamped parts are analyzed using an axi-symmetrical theory of elasticity. Using the obtained results, an increment in the axial bolt force and the reduction in the bolt preload are estimated. For verification of the FEM stress analysis, the load factor of hexagon bolt was measured. The FEM results of the load factor (the increment in the axial bolt force) and the axial bolt force are in a fairly good agreement with the experimental results and the reduction of the axial bolt force. Finally, discussion is made on the appreciate bolt preload.

Study on Bearing Behaviors of Bolted Joints in Composite Laminates

2013 ◽  
Vol 652-654 ◽  
pp. 1509-1513
Author(s):  
Tao Huang ◽  
Zhe Su
Keyword(s):  
Experimental Investigation ◽  
Finite Element ◽  
Finite Element Model ◽  
Composite Laminates ◽  
Element Model ◽  
Bolted Joints ◽  
Stress And Strain ◽  
Bolted Joint ◽  
Bearing Stress ◽  
The Relationship

An experimental investigation was conducted to determine the bearing stress of single-lap double bolted composite joints. The bearing stress of a group of specimen was presented and the relationship between the stress and strain was obtained. The experimental results show that the damage of the bolted joints was a progressive process; and the ultimate bearing stress depends not only on the laminates’ strength but also on the bolt strength. A finite element model was created based on the bolted joint specimen to simulate the loading – displacement response. The numerical results verified the experiment results qualitatively.

The Research on the Torque-Tension Relationship for Bolted Joints

2011 ◽  
Vol 486 ◽  
pp. 242-245 ◽  
Author(s):  
Jun Huang ◽  
Lian Shui Guo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bolted Joints ◽  
Fe Modeling ◽  
Bearing Surface ◽  
Element Analysis ◽  
Helical Geometry ◽  
Relationship Of ◽  
The Relationship

This paper has proposed an improved formula for the torque-tension relationship of bolted joints with consideration of all forces and moments acting on fasteners. Finite element analysis (FEA) is used to analyze and evaluate the relationship. An effective finite element (FE) modeling scheme which considers the helical geometry is developed. Effects of contact radii ratios of the nut bearing surface on the percentages of component torques are investigated. Percentages of component torques are calculated according to present and conventional formula, to compare with FEA results.

A Bolt-Nut Loosening Mechanism in Bolted Connections Under Repeated Transverse Loadings (Effect of Inclined Bearing Surfaces on the Loosening)

2010 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Mitsutoshi Ishimura ◽  
Atsushi Karami
Keyword(s):  
Testing Machine ◽  
Bolted Joints ◽  
Incline Angle ◽  
Impact Loads ◽  
Screw Thread ◽  
Bolted Joint ◽  
Bearing Surface ◽  
Bolted Connections ◽  
Inclined Surfaces ◽  
Thermal Changes

Loosening accidents sometimes occur under several types of loadings such as winds, vibrations, earthquakes, impact loads and thermal changes. Recently, some studies have been conducted on the screw thread loosening in bolted joints under repeated transverse loadings. It is well known that bolted joints are easily loosened when repeated transverse loadings are applied. While, in assembling bolted joints, the contact surfaces between a bolt head/nut and a clamped part are inclined geometrically. However, a lot of researches have dealt with the bolted joints in which the bearing surfaces are perfectly contacted without the inclined surfaces. Thus, it is necessary to examine the incline of the bearing surfaces on the loosening in bolted joint. A lot of parts for preventing the loosening have been proposed and sold at market. Among these parts, the authors have demonstrated that eccentric nuts are especially expected to be the solution for preventing the loosening of the joints under repeated transverse loadings. However, a few studies have been carried out on the loosening and loosening mechanism in bolted joints with inclined bearing surface and the effective solution for preventing loosening of bolted joint with the inclined bearing surfaces under the repeated transverse loadings. Thus, it is necessary to examine the effect of the incline at the bearing surfaces on the loosening and to evaluate the solutions for preventing loosening of the bolted joints with the inclined bearing surfaces. In this study, the effect of the incline at the bearing surfaces on the loosening is examined using FEM calculations. In the FEM calculations, the incline angle at the bearing surfaces is changed as 0, 2 and 3 degree, respectively. The experiments to measure the loosening in bolted joints were carried out using Junker’s testing machine to validities of the FEM calculations for revealing the effect of the loosening in the joints with the inclined bearing surfaces. In addition, nut parts for preventing the loosening in bolted connections with the inclined bearing surface under repeated transverse loadings are examined using the FEM calculations. As the result, it is seen that the loosening increases as the angle of incline increases. In addition, it is observed that bolted joints in which almost nut parts for preventing loosening are applied are loosened easily while the eccentric nut does not loosened. Discussion is made on the loosening mechanism in bolted joints under repeated transverse loadings.

scholarly journals Preload Effect Elimination Technique for Piezoelectric Force Touch Sensing in Human-Machine Interactivities

2020 ◽  
Author(s):  
Jiahui Shi ◽  
Junliang Chen ◽  
Jingjing Lin ◽  
Shuo Gao
Keyword(s):  
Piezoelectric Materials ◽  
Experimental Results ◽  
Detection Sensitivity ◽  
Detection Accuracy ◽  
Static Force ◽  
Force Detection ◽  
Voltage Responsivity ◽  
The Relationship ◽  
Interactive Displays

Piezoelectric touch sensing in interactive displays gains increasing attentions due to its high force detection sensitivity and intrinsic mechanical-to-electrical conversion ability. However, the instable force-voltage responsivity induced by preload effect of piezoelectric materials reduces the force detection accuracy of secondary force touches, which is important to touch and haptic applications such as peek-pop. To address this issue, in this article, we present a preload effect elimination technique, in which the relationship between the piezoelectric coefficients and static preload is studied first, and then the detected secondary force touch is calibrated by using the previously applied static force information. Experimental results demonstrate that the force detection accuracy is boosted by 15.17% after applying the developed technique to secondary force touches with different preload values, potentially allowing the system to precisely interpret secondary force touch amplitude and hence enhancing the development of touch sensing in interactive displays.

scholarly journals Preload Effect Elimination Technique for Piezoelectric Force Touch Sensing in Human-Machine Interactivities

2020 ◽  
Author(s):  
Jiahui Shi ◽  
Junliang Chen ◽  
Jingjing Lin ◽  
Shuo Gao
Keyword(s):  
Piezoelectric Materials ◽  
Experimental Results ◽  
Detection Sensitivity ◽  
Detection Accuracy ◽  
Static Force ◽  
Force Detection ◽  
Voltage Responsivity ◽  
The Relationship ◽  
Interactive Displays

Piezoelectric touch sensing in interactive displays gains increasing attentions due to its high force detection sensitivity and intrinsic mechanical-to-electrical conversion ability. However, the instable force-voltage responsivity induced by preload effect of piezoelectric materials reduces the force detection accuracy of secondary force touches, which is important to touch and haptic applications such as peek-pop. To address this issue, in this article, we present a preload effect elimination technique, in which the relationship between the piezoelectric coefficients and static preload is studied first, and then the detected secondary force touch is calibrated by using the previously applied static force information. Experimental results demonstrate that the force detection accuracy is boosted by 15.17% after applying the developed technique to secondary force touches with different preload values, potentially allowing the system to precisely interpret secondary force touch amplitude and hence enhancing the development of touch sensing in interactive displays.

Sign in / Sign up

Export Citation Format

Share Document