Influence of Structural Interface Opening of Bolted Joints Under Eccentric Load

2020 ◽  
Author(s):  
Makoto Imura ◽  
Takayuki Koyama ◽  
Motonobu Iizuka ◽  
Yasushi Hayasaka
Keyword(s):  
Evaluation Method ◽  
Bolted Joints ◽  
Eccentric Load ◽  
Stress Evaluation ◽  
Clamped Plate ◽  
Pull Out ◽  
Structural Interface ◽  
Bolt Stress ◽  
Similarity Rule ◽  
Bolt Diameter

Abstract It is important to evaluate the safety of bolted joint under a load eccentric to a bolt axis. We examined tapped thread joints, with which a clamped plate is tightened with bolts to a base body, by applying eccentric loads to the bolts. The structural interface opening between the clamped plate and base body occurs due to the eccentric load based on the principle of leverage. During the growth of the interface opening, nonlinearity noticeably appears on the tensional and bending components of bolt stress, and these stress components become larger than expected in an early phase before a fatal bolt pull-out occurs. However, an evaluation method taking into account nonlinearity has not been investigated. We propose a normalized-bolt-stress evaluation method for tapped thread joints that takes into account the effect of the nonlinearity of bolt stress during interface opening. We conducted numerical calculations, experiments, and finite element analyses to quantitatively validate the stress under the following conditions: (i) tapped thread joints with the clamped plate thinner than the bolt diameter and (ii) load eccentric to the bolt axis. We confirmed that the bolt preload and lever ratio should be fixed at an initial phase, in which has no interface openings for the appropriate normalization. By using the normalized-bolt-stress evaluation method, strength evaluation becomes easily applicable to layout changes of bolted joints as a similarity rule.

A Normalized Stress of Pull-Out Action on Bolted Joints Under Eccentric Load

2018 ◽  
Author(s):  
Makoto Imura ◽  
Takayuki Koyama ◽  
Motonobu Iizuka ◽  
Takayuki Suzuki
Keyword(s):  
Axial Direction ◽  
Bolted Joints ◽  
Eccentric Load ◽  
Stress Evaluation ◽  
Centrifugal Load ◽  
Pull Out ◽  
Bolt Preload ◽  
Structural Interface ◽  
Bolt Stress ◽  
Bolt Diameter

Our objective is to evaluate precisely a life-cycle of bolted joints under an eccentric load against a bolt axis. Many approaches to achieve the objective based on a lot of theories and practices have been proposed so far [1–12]. As we can refer from their approaches, the opening of the structural interface between clamped plates of bolted joints occurs by the eccentric load, which is over a bolt preload, and then the opening gradually propagates as the eccentric load increases. In the case, nonlinearity appears remarkably on the tensional and bending stress of bolts in the axial direction. In addition to the above, the axial bolt stress larger than expected occurs due to the principle of leverage depending on the load position and the bolted joints layout in the early phase of the pull-out action. Accordingly, the stress evaluation of bolted joints under the eccentric load is very important in order to ensure the safety of industrial machines. If dimensionless quantities of the bolt stress are found out considering the influence of the structural opening and the load eccentricity, we can have a few advantages as follows. First, bolt stress evaluations can be conducted by easily converting the dimensionless quantities of the bolt stress to the physical dimension quantities in a lot of cases where the bolt preload and the load eccentricity are different. Second, the number of times of verification tests can be reduced. We are developing a lot of industrial machines which have bolted joints used under eccentric load. In such development [13], bolt stress analyses are usually conducted under the combinations of the following conditions: (i) tapped thread joints, (ii) thin clamped plates than the bolt diameter, (iii) large eccentric loads, (iv) permitting the opening of the structural interface. Therefore, we propose a concept of a normalized bolt stress considering the effect of the structural opening and the load eccentricity. We validated this concept through theoretical studies, finite element analyses, and experiments under the direct load and the centrifugal load. As a result, the dimensionless quantities of the bolt stress caused by the bolt preload and a lever ratio of bolted joints under combined conditions was determined in this study. We can easily evaluate the bolt stress by simple conversions in a lot of cases in which the bolt preload and the load eccentricity differ.

Finite-Element Analysis of the Load Factor and Design for Bolted Circular Flange Joints Consisting of Dissimilar Clamped Parts Under Tensile Loadings

2019 ◽  
Author(s):  
Shunichiro Sawa ◽  
Yasuhisa Sekiguchi ◽  
Toshiyuki Sawa
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Design Method ◽  
Bolted Joints ◽  
Load Factor ◽  
Bending Stress ◽  
Element Analysis ◽  
Bolt Stress ◽  
Bolt Diameter ◽  
Circle Diameter

Abstract The load factor for bolted circular flange joints where two dissimilar material (steel-aluminum) of circular flanges are clamped by a lot of bolts and nuts under external tensile loadings is examined newly using Finite Element analysis. Furthermore, the effects of the bolt pitch circle diameter D and number of tightened bolts N on the load factor and a load when the interfaces start to separate are examined. The value of the load factor for steel-aluminum circular flange joint is a little bit larger than that for steel-steel circular flange joints and it increases as the value of D decreases. In addition, it decreases as the value of N increases. A maximum bending stress is also found newly about 5% larger than the bolt stress due to the load factor. The experiments to measure the load factor, the maximum bending bolt stress and a load when the interfaces start to separate were carried out. The FEM results are fairly coincided with the experimental results. Finally, based on the obtained load factor, a design method for bolted joints with dissimilar circular flanges is demonstrated for determining the nominal bolt diameter and the bolt strength grade and the effect of bolt number N is examined. It is found that the contact stress at the bearing surfaces of aluminum circular flange is critical and it is shown that washers are needed in some cases.

602 Stress Evaluation Method of Bolted Joints under Eccentric Force

2014 ◽  
Vol 2014 (0) ◽  
pp. 151-152
Author(s):  
Makoto IMURA ◽  
Takayuki KOYAMA ◽  
Kazuhiro OGAWA ◽  
Shigeki NAKAE ◽  
Motonobu IIZUKA
Keyword(s):  
Evaluation Method ◽  
Bolted Joints ◽  
Stress Evaluation

Influence of Structural Interface Opening of Bolted Joints Under Eccentric Load

2021 ◽  
Author(s):  
Makoto Imura ◽  
Takayuki Koyama ◽  
Motonobu Iizuka ◽  
Yasushi Hayasaka
Keyword(s):  
Bolted Joints ◽  
Eccentric Load ◽  
Structural Interface

Stress Analysis and the Characteristics of T-Shape Bolted Joints Under Tensile Loadings

2005 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Seiichi Hamamoto
Keyword(s):  
Bending Moment ◽  
Theory Of Elasticity ◽  
Bolted Joints ◽  
Load Factor ◽  
Two Dimensional ◽  
Bolted Joint ◽  
Dimensional Theory ◽  
Matching Method ◽  
Point Matching ◽  
Bolt Stress

In designing a bolted joint, it is important to examine the interface stress distribution (clamping effect) and to estimate the load factor, that is the ratio of an additional axial bolt force to a load. In order to improve the clamping effect raised faces of the interface have been used. But these interfaces in bolted joints have been designed empirically and the theoretical grounds are not made clear. In the present paper, in the case of T-shaped flanges with raised faces the clamping effect is analyzed by a two-dimensional theory of elasticity and the point matching method. Then, the load factor is analyzed. Moreover, with the application of the load a bending moment is occurred in bolts and the stress is added due to this bending moment. The bending moment in the bolt is also analyzed. In order to verify these analyses experiments to measure the load factor and the maximum bolt stress were carried out. The values of the load factor and the load when interface start to separate are compared with those of the joints with flat-faces. The analytical results are in fairly good agreements with the experimental ones.

scholarly journals Experimental and semianalytical investigation of X850 ± IM190 CFRP bolted joints

2020 ◽  
Vol 29 ◽  
pp. 096369351989500
Author(s):  
Boling He
Keyword(s):  
Bolted Joints ◽  
Design Parameters ◽  
Material System ◽  
Commercial Aircraft ◽  
Reinforced Polymer ◽  
Epoxy Material ◽  
Static Tensile ◽  
Curing Method ◽  
Tensile Experiment ◽  
Bolt Diameter

Considering the fact that the foundation data for a new X850 ± IM190 carbon/epoxy material system adopted in commercial aircraft industry are extremely scarce in the literature, an in-plane, static tensile experiment was carried out to investigate the bearing performance of double-lap, single-bolt joints in X850 ± IM190 carbon fiber-reinforced polymer (CFRP) composites. The effects of ply ratio, 0° layers’ combination percentage, bolt diameter, and curing method were considered. Then, special attention was paid to determine the design parameters of X850 ± IM190 CFRP bolted joints, such as tensile strength of un-notched laminate and stress concentration relief factor. Based on these design parameters, an efficient semianalytical approach was established to obtain the ultimate bearing strength of the joints. The failure prediction exhibited excellent agreement with the experimental data. These results will play an important role in design and strength evaluation of X850 ± IM190 CFRP bolted joints.

Review of FE-Based Fatigue Evaluation Methods for the Rib to Floorbeam Welds in Orthotropic Bridge Decks

2014 ◽  
Vol 627 ◽  
pp. 337-340
Author(s):  
Wouter de Corte ◽  
Arne Jansseune
Keyword(s):  
Evaluation Method ◽  
Hot Spot ◽  
Bridge Decks ◽  
High Stress ◽  
International Institute ◽  
Element Analysis ◽  
Stress Evaluation ◽  
Linear Elastic ◽  
Mesh Density ◽  
Fatigue Evaluation

Complex welded structures such as bridges are very often designed with the help of FE analysis. However, one should remain cautious when using such an analysis, since the results are mesh sensitive, with especially the mesh density and the element type influencing the results. In addition, these results are in most cases retrieved in hot spot areas with high stress gradients, where the maximum stress even cannot be correctly determined with linear elastic finite element analysis. For that reason, a stress evaluation method is required to obtain relevant stress levels that can be directly related to fatigue detailing. The most complete set of stress evaluation recommendations is given in the Recommendations for Fatigue Design of Welded Joints and Components from the International Institute of Welding. Nevertheless, several authors have recently commented on the difficulties regarding the application of these methods for the rib to floorbeam welds in orthotropic bridge decks. This paper provides findings for this type of connections based on both shell and solid model analysis and relates these findings to work from other authors.

A Normalized Stress Analysis of Bolted Joints under Eccentric Load

2017 ◽  
Vol 2017 (0) ◽  
pp. 505
Author(s):  
Makoto IMURA ◽  
Takayuki KOYAMA ◽  
Misato SATO
Keyword(s):  
Stress Analysis ◽  
Bolted Joints ◽  
Eccentric Load

scholarly journals Experimental Study on Bond-Slip Behavior of Bamboo Bolt-Modified Slurry Interface under Pull-Out Load

2018 ◽  
Vol 2018 ◽  
pp. 1-23 ◽  
Author(s):  
Wei Lu ◽  
Dong Zhao ◽  
Xiao-fei Mao ◽  
Yu Ai
Keyword(s):  
Axial Direction ◽  
Impact Factors ◽  
Slip Model ◽  
Distribution Law ◽  
Bond Slip ◽  
Pull Out ◽  
Control Interface ◽  
Bolt Diameter ◽  
Interface Bond

This paper presents an analysis of bamboo bolt-modified slurry interfaces based on 26 in situ axial pull-out tests intended to highlight the mechanical behavior of interface under a fracture mode. Three impact factors are analyzed: anchorage length, bolt diameter, and bolt hole diameter, using the same materials of bamboo and modified slurry. The result shows that the interface between the bamboo bolt and anchoring agent is the control interface of an anchorage system, and the local behavior of the interface involves four stages: elastic, soften, friction, and decoupling. Distribution law and change trend of slippage, stress, and strain of anchoring interface along with the axial direction of an anchor bolt were analyzed. The result shows that there is effective anchoring length limit in this kind of interface, and that the complete decoupling phenomenon should not be neglected. Through a comparative analysis of the existing bond-slip model and interface bond-slip curve, and considering the correspondence of the strain-slip curve and trilinear bond-slip model simultaneously, a modified trilinear bond-slip model has been proposed. The friction section of this model is limited, and shearing stress in the complete decoupling section is zero.

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