Analysis of the States of Deformation and Stress in the Surface Layer of the Product after the Burnishing Cold Rolling Operation

Abstract

The article presents the results of computer modelling and numerical simulations the deformation and stresses occurring in the surface layer of the product after the burnishing cold rolling operation. Technological processes were considered as a geometrical and physical boundary and initial value problem, with unknown boundary conditions in the contact zone. An incremental model of the contact problem between movable rigid or elastic body (tool) and elastic/visco-plastic body (object) in updated Lagrange formulation, for spatial states (3D) was considered. The incremental functional of the total energy and variational, non-linear equation of motion and deformation of object on the typical step time were derived. This equation has been discretized by finite element method, and the system of discrete equations of motion of objects was received. For solution of these equations the explicit methods was used. The applications were developed in the ANSYS/LS-Dyna system, which makes possible a complex time analysis of the states of displacements, strains and stresses, in the workpieces in fabrication processes. Application of this method was showed for examples the modelling and the analysis of the asperities with apex angles θ = 85°, 120° and 156°. The Bielajew point using finite elements methodology was indicated. The simulation results were verified experimentally.

Application of the FEM Method to Modeling and Analysis of the Cold Thread Rolling Process—Part 1: Conditions for Ensuring a Plane State of Deformations

“…As a result, for successive discrete moments of time τ 0, Δt, 2Δt, … the geometry of the body and the states of incremental displacements, displacement velocities, accelerations, strains, strain rates, and stresses are determined. The concept of incremental description has already been verified by the author and was used to describe other plastic-forming processes: cutting [36][37][38][39][40][41][42], thread rolling [15][16][17]28,29], burnishing rolling [43][44][45][46][47][48][49], drawing [50][51][52], grinding with a single abrasive grain [53], calculating the fatigue strength of products [54][55][56], and diamond sliding burnishing [56].…”

“…The increment of the yield stress at a typical step t → t ∆t is defined by the following equation [44]:…”

Impact of Processing Parameters on Surface Roughness and Strain Hardening of Two-Phase Stainless Steel

“…The selection of burnishing conditions is based on approximate calculations of forces and unitary pressures, experimental results of materials with similar properties, universal nomograms, and specialist norms [3,7,8,10,15]. For cases where there are insufficient certain dependencies and nomograms and for burnishing with simultaneous cutting, the selection of conditions should be made on the basis of preliminary tests [3][4][5][6][7][8][9][10][14][15][16]. The technological process resulting in low surface roughness should be realized with application of as much pressure as possible on the surface of the treated element, while the speed of the burnishing and the feed rate should be low.…”

Abrasive Water Jet Cutting of Stainless-Steel Optimization by Orthogonal Array Approach

“…Among the modern production technologies, environmentally-friendly ones deserve special attention. It is mostly plastic processing [1,2] and high-pressure water jet technology [3]. Use of conventional coolants in traditional machining and grinding is being looked upon critically from the point of view of its impact on the environment.…”

“…The high cutting depth enables efficient cutting. For this reason, ratio η (S / N) "bigger is better" represented by the equation (1) was selected for further analysis.…”