scholarly journals Dynamic Analysis and Looseness Evaluation of Bolted Connection Under Vibration of Machine Tools

2021 ◽  
Author(s):  
Wenxiang Xu ◽  
Qiang Cheng ◽  
Congbin Yang ◽  
Ying Li
Keyword(s):  
Dynamic Analysis ◽  
Machine Tools ◽  
Design Method ◽  
Bolted Joints ◽  
Quadratic Regression ◽  
Bolted Connection ◽  
Bolt Preload ◽  
Attenuation Rate ◽  
Experimental Design Method ◽  
Analytical Result

Abstract Bolted connections are widely used in the machine tool manufacturing and equipment. As it is well known, bolt preload will be attenuated by the vibration of machine tools, which will degenerate the working life of machine tools. In this paper, a new experimental design method is introduced into the study on bolt preload attenuation: the quadratic general rotary unitized design. The dynamic analysis of the bolted connection is carried out based on a finely fragmented numerical model to interpret the generation of fretting slip and the reason for the loosening of bolts. The alternating load cyclic vibration test, implemented on the bolted joints, can provide the vibration response under the influence of different working factors. Statistical test and analysis are performed on the quadratic regression mathematical model of the bolt preload attenuation, and the principal working factor that affecting the bolt preload attenuation under vibration can be obtained. Based on the analytical result, the combination of the working factors at the lowest bolt preload attenuation rate, which can effectively slow the bolt looseness, is investigated. The results of this study can provide an experimental basis for improving the machining stiffness of machine tools.

FEM Stress Analysis and the Load Factor of Bolted Joints Consisting of Dissimilar Hollow Cylinders Under Tensile Loads

2017 ◽  
Author(s):  
Shunichiro Sawa ◽  
Mitsutoshi Ishimura ◽  
Yasuhisa Sekiguchi ◽  
Toshiyuki Sawa
Keyword(s):  
Hollow Cylinder ◽  
Design Method ◽  
Tensile Load ◽  
Bolted Joints ◽  
Load Application ◽  
Load Factor ◽  
Application Point ◽  
Bolt Preload ◽  
Hollow Cylinders ◽  
Bolt Diameter

In designing a bolted joint consisting of dissimilar hollow cylinders, the load factor (the ratio of an increment in axial bolt force to an external tensile load) is important. In the present paper, the effect of the load application point, the ratio b/a of the outside diameter to the inside diameter of dissimilar hollow cylinders, Young’s modulus ratio between the dissimilar hollow cylinders on the load factor and the interface stress distribution are examined using FEM calculations. As a result, it is found that the values of the load factor decrease as the ratio b/a increases and the positions where the load application point approaches the interfaces while the value of the load factor is independent of the bolt preload. In addition, it is found that the value of the load factor is less than 0.1 for steel and steel hollow cylinder joints, it is less than 0.2 for aluminum and aluminum hollow cylinder joints and it is less than 0.15 for aluminum and steel hollow cylinder joints while the material of bolt is steel in the present study. For verification of the FEM calculations, experiments to measure the load factor and a load when the interfaces start to separate were carried out. The FEM results are in a fairly good agreement with the experimental results. Finally, based on the obtained results, a design method for bolted joints with dissimilar hollow cylinders is demonstrated for determining the nominal bolt diameter and the bolt strength grade.

A Simplified Model of SSI Dynamic Analysis

2012 ◽  
Vol 446-449 ◽  
pp. 334-339
Author(s):  
Zhi Ying Zhang ◽  
Ying Li ◽  
Qing Sun
Keyword(s):  
Dynamic Analysis ◽  
Soil Structure ◽  
Design Method ◽  
Simplified Model ◽  
Lumped Mass ◽  
Foundation Soil ◽  
Linear Elastic ◽  
Lumped Mass Method ◽  
Actual Mechanism ◽  
Seismic Design Method

Aiming at the problem of dynamic analysis of SSI system, the dynamic influence of different parts of foundation soil is studied on the linear elastic assumption according to the actual mechanism of Soil-Structure Interaction (SSI); in addition, a simplified model on the condition of the lumped mass method is put forward and the corresponding motion equations of SSI system are built, which can be a reference for the structural seismic design method considering SSI effect.

An efficient design method for multi-material bolted joints used in the railway industry

2011 ◽  
Vol 94 (1) ◽  
pp. 246-252 ◽  
Author(s):  
G. Catalanotti ◽  
P.P. Camanho ◽  
P. Ghys ◽  
A.T. Marques
Keyword(s):  
Design Method ◽  
Bolted Joints ◽  
Efficient Design ◽  
Railway Industry

A New Approach for Determining Joint Stiffness of Bolted Joints

2014 ◽  
Vol 670-671 ◽  
pp. 1041-1044 ◽  
Author(s):  
Xi Wang Wang ◽  
Xiao Yang Li ◽  
Lin Lin Zhang ◽  
Xiao Guang Wang
Keyword(s):  
Accurate Determination ◽  
Joint Stiffness ◽  
Fatigue Loading ◽  
Bolted Joints ◽  
Analytical Models ◽  
Bolted Connection ◽  
New Approach ◽  
Axisymmetric Model ◽  
Force Equilibrium

Joint member stiffness in a bolted connection directly influence the safety of a design in regard to both static and fatigue loading as well as in the prevention of separation in the connection. Thus, the accurate determination of the stiffness is of extreme importance to predict the behavior of bolted assemblies. In this paper, An analytical 3D axisymmetric model of bolted joints is proposed to obtain the joint stiffness of Bolted Joints. Considering many different analytical models have been proposed to calculate the joint stiffness, the expression based force equilibrium can be a easy way to choose the best expression for the joint stiffness as a judgment criteria.

Performance Evaluation of Coating Materials Containing Perlite-Volcanic Lava Stone-Carrot Pulp Ternary System

2021 ◽  
Vol 43 (6) ◽  
pp. 635-635
Author(s):  
Bilge elik and Nil Acaral Bilge elik and Nil Acaral
Keyword(s):  
Design Method ◽  
Optimization Method ◽  
Natural Polymer ◽  
Organic Additives ◽  
Coating Materials ◽  
Pumice Stone ◽  
Design Expert ◽  
Experimental Design Method ◽  
Volcanic Lava ◽  
Suitable Process

Cellulose in the fibrous structure, which is the main structural component in the cell wall of plants, was formed by the combination of three thousand or more glucose molecules and was a natural polymer synthesized by many living microorganisms. In this study, it was aimed to observe the performance of carrot pulp physically added to water-based coating to increase the viscosity of the coatings. In addition, volcanic lava stone (red pumice stone) and perlite stone were added to the coating to improve its properties that heat transfer, adhesion, hydrophobicity, corrosion resistance. The effect of cellulose-based material on the viscosity of the coating was determined using the Design Expert Optimization Method. In this experimental design method, the experimental set was created to be “carrot pulp, volcanic lava stone, and perlite stone” and additives was added as 0-6% by weight of the coating. By using this method, the most suitable process parameters were determined, and the effects of the additives added to the coating were examined, comparatively. As a result, it was found that cellulose derived organic additives and other additives improved the various properties of coating and could be evaluated for industrial coatings.

scholarly journals Treatment of bedsores-Combination of therapies depended the experimental design method-

2005 ◽  
Vol 42 (1) ◽  
pp. 90-98
Author(s):  
Hiroko Miyaji ◽  
Hirofumi Sakurai ◽  
Masayuki Kikawada ◽  
Katsuhiko Yamaguchi ◽  
Akihiro Kimura ◽  
...  
Keyword(s):  
Experimental Design ◽  
Design Method ◽  
Experimental Design Method

Application of Tree Graph Method for Reducing the Total Time of Tool Changing in Milling and Boring Machine Tools

2013 ◽  
Vol 371 ◽  
pp. 431-435 ◽  
Author(s):  
Claudiu Obreja ◽  
Gheorghe Stan ◽  
Lucian Adrian Mihaila ◽  
Marius Pascu
Keyword(s):  
Machine Tools ◽  
Design Method ◽  
Machining Process ◽  
Cnc Machine Tools ◽  
Tree Graph ◽  
Cnc Machine ◽  
High Productivity ◽  
Automatic Tool Changer ◽  
Automatic Tool ◽  
Set Up

With a view of increasing the productivity on CNC machine tools one of the main solution is to reduce, as much as possible, the auxiliary time consumed with the set-up and replacement of the tools and work pieces engaged in the machining process. Reducing the total time of the tool changing process by the automatic tool changer system can be also achieved through minimizing the number of movements needed for the actual exchange of the tool, from the tool magazine to the machine spindle (the optimization of the tool changing sequences). This paper presents a new design method based on the tree-graph theory. We consider an existing automatic tool changing system, mounted on the milling and boring machining centre, and by applying the new method we obtain all the possible configurations to minimize the tool changing sequence of the automatic tool changer system. By making use of the method proposed we obtain the tool changing sequences with minimum necessary movements needed to exchange the tool. Reconfiguring an existing machine tool provided with an automatic tool changer system by making use of the proposed method leads to obtaining the smallest changing time and thus high productivity.

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