Stress concentration effect on deflection and stress fields of a master leaf spring through domain decomposition and geometry updation technique

2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Sushanta Ghuku ◽  
Kashi Nath Saha
Keyword(s):  
Stress Concentration ◽  
Domain Decomposition ◽  
Governing Equation ◽  
Experimental Results ◽  
Image Processing Technique ◽  
Concentration Effect ◽  
Leaf Spring ◽  
Curved Beam ◽  
Variable Cross ◽  
Stress Concentration Effect

Abstract Theoretical and experimental large deflection and stress analysis of a master leaf spring considering stress concentration effect of clamping is reported. The non-uniformly curved master leaf spring under three point bending subjected to moving boundaries is modeled. Geometrically nonlinear strain-displacement relations, as necessary for the theoretical analysis, are derived through visualization of physics behind the large deformation problem. An embedded curvilinear coordinate system is considered, to study the combined effects of non-uniform curvature, bending, stretching and shear deformation including cross-sectional warping. Governing equation of the non-uniformly curved beam system is derived in variational form using energy method, based on linear material constitutive relations and the derived nonlinear kinematic relations. An iterative solution scheme through successive geometry updation is developed and executed in MATLAB® software to solve the governing equation involving strong geometric nonlinearity together with complicating moving boundary effect. Experimental deflection profiles under static loading are obtained through manual image processing technique using AutoCAD® software. Whereas, strain measurements are performed using strain gauges with data acquisition system (HBM-MX840B). Comparison between the theoretical and experimental results lead towards observation on stress concentration effect due to presence of geometric discontinuity in form of a small hole in the physical system. A modified formulation is proposed using domain decomposition method incorporating effect of geometric discontinuity through an equivalent curved beam geometry of variable cross-section. The modified theoretical model is validated successfully with the experimental results, and observations on stress characteristics and effect of hole diameter to beam width ratio are made.

Enhancing weak magnetic field MME coupling in NdFeB magnet/piezoelectric composite cantilevers with stress concentration effect

2021 ◽  
Vol 118 (13) ◽  
pp. 132902
Author(s):  
Zhonghui Yu ◽  
Zhaoqiang Chu ◽  
Jikun Yang ◽  
Mohammad Javad Pourhosseini Asl ◽  
Zhanmiao Li ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Stress Concentration ◽  
Weak Magnetic Field ◽  
Concentration Effect ◽  
Piezoelectric Composite ◽  
Ndfeb Magnet ◽  
Stress Concentration Effect

Theoretical Modeling of Steel Strip Reinforced Flexible Pipe With Swaging End Fitting by Taking Into Account Stress Concentration Effect

2019 ◽  
Author(s):  
Yifan Gao ◽  
Wei Chen ◽  
Yong Bai
Keyword(s):  
Stress Concentration ◽  
Internal Pressure ◽  
Steel Strip ◽  
Displacement Discontinuity ◽  
Concentration Effect ◽  
Elastic Model ◽  
Thin Wall ◽  
Burst Strength ◽  
Joint Area ◽  
Stress Concentration Effect

Abstract A new theoretical model was proposed to calculate the burst pressure of steel strip reinforced flexible composite pipes (steel strip PSP) based on the thin wall cylindrical shell theory and the squeeze pressure expression between layers was derived. The radial displacement discontinuity of pipe wall in pipe-end fitting joint area takes in account in this model which could result in Stress Concentration Effect (SCE) in reinforcement layers. The SCE is caused by swaging end fitting clamped tightly at the end of the pipe. The result of the hoop strain in the joint area calculated by this model is greater than the one calculated by the classic elastic model, which leads to relative conservative burst strength of the pipe. The hoop stress variation via internal pressure on innermost reinforcement layer is introduced to predict the burst strength of the pipe. As the stress in the joint area reaches its ultimate strength, the strain on the same layer in the point far away from this area (x→∞) is extracted and the corresponding internal pressure is obtained as the burst strength of the pipe. The calculated data from two models were compared with the experiment results and the proposed new model showed better accuracy than the classic elastic model. Final additional parametric studies were conducted, while the effect of the pipe diameter, the winding angle, the number and thickness of the reinforcement layer on the burst strength of the pipe were studied. Useful conclusions were drawn for the design and application of the steel strip PSP in offshore engineering.

Experimental investigation on new low cycle fatigue precision cropping process

2014 ◽  
Vol 229 (8) ◽  
pp. 1470-1476 ◽  
Author(s):  
Renfeng Zhao ◽  
Shengdun Zhao ◽  
Bin Zhong ◽  
Yong Tang
Keyword(s):  
Stress Concentration ◽  
Cross Sections ◽  
Low Cycle Fatigue ◽  
Fatigue Loading ◽  
High Energy ◽  
Concentration Effect ◽  
Cycle Fatigue ◽  
Stable Crack Propagation ◽  
New Type ◽  
Stress Concentration Effect

The traditional cropping processes have some disadvantages, such as poor surface quality, low yield, the waste of materials, and high energy consumption. The low cycle fatigue precision cropping process with circumferential loading, which is a new type of precision cropping process, is studied. According to the stress concentration effect of the V-shape notch, the fatigue crack on the tip of the V-shape notch is prompted to initiate and extend. The working principle of the precision cropping machine is described. The criterion that whether the crack on the root of the V-shape notch is initiated or not is provided under the effect of low cycle fatigue loading. The materials which are 0.2%C steel, H59 copper, 0.45%C steel, 20Cr steel, and LY12 aluminum are tested under two control curves. The initiation and propagation of crack are accelerated and the good cross sections of the metal bar are obtained. The results show that the mean stress of the metal bar in the cropping process can be effectively reduced due to the stress concentration effect of the V-shape notch. The metal bar’s stable crack propagation and fracture can be obtained when constantly increasing striking displacement and reducing the striking frequency in the cropping process at the same time in the process.

Stiffness analysis of leaf spring system under large deformation

2020 ◽  
Vol 234 (12) ◽  
pp. 2487-2508
Author(s):  
Sushanta Ghuku ◽  
Kashinath Saha
Keyword(s):  
Finite Element ◽  
Large Deformation ◽  
Governing Equation ◽  
Parametric Study ◽  
Elastic Behavior ◽  
Leaf Spring ◽  
Curved Beam ◽  
Total System ◽  
Constrained Motion ◽  
Spring System

The paper proposes a semi-analytical model to analyze large deformation elastic behavior of leaf spring under static load. The model treats leaf spring system as a curved beam with one end directly hinged to a fixed support and the other end being attached to another fixed support through a rigid link (shackle). Constrained motion of the shackle with large deformation of curved beam is modeled using a rotational spring at fixed hinge point of the shackle. Two more physically plausible models for the restraint motion are also proposed, which are derived from the main model through post processing. In the first derived model, the constrained motion is captured by defining a longitudinal spring in a virtual rod connecting the curved beam ends, whereas in the second derived model, the restrained motion is modeled through vertical stiffness of the system. Due to combined complications coming from non-conventional boundary condition, asymmetric geometry, non-uniform curvature, and nonlinear kinematics, the problem is analyzed through successive geometry updation. Governing equation for the curved beam is derived in body fitted curvilinear frame considering combined bending–stretching effects. Global solution for the total system is then obtained by incorporating the elastically restrained shackle motion through satisfaction of kinematic and kinetic constraint relations. As the governing equation and the constraint conditions involve geometric nonlinearity, a numerical iterative scheme is developed and implemented in MATLAB®. For the purpose of validation, the theoretical model is simulated in commercial finite element package ABAQUS®. Comparison of deflection profiles with the finite element model validates the proposed leaf spring model. After the validation study, observations on effects of system parameters and curved leaf profile shape on system stiffnesses are furnished. Effects of the parametric study are presented through true and total system stiffnesses. The parametric study may lead toward optimized design of the system.

Sign in / Sign up

Export Citation Format

Share Document