Two contact problems in anisotropic thermoelasticity

In this paper, we study the steady-state rolling contact of a linear viscoelastic layer of finite thickness and a rigid indenter made of a periodic array of equally spaced rigid cylinders. The viscoelastic contact model is derived by means of Green’s function approach, which allows solving the contact problem with the sliding velocity as a control parameter. The contact problem is solved by means of an accurate numerical procedure developed for general two-dimensional contact geometries. The effect of geometrical quantities (layer thickness, cylinders radii, and cylinders spacing), material properties (viscoelastic moduli, relaxation time) and operative conditions (load, velocity) are all investigated. Physical quantities typical of contact problems (contact areas, deformed profiles, etc.) are calculated and discussed. Special emphasis is dedicated to the viscoelastic friction force coefficient and to the energy dissipated per unit time. The discussion is focused on the role played by the deformation localized at the contact spots and the one in the bulk of the thin layer, due to layer bending. The model is proposed as an accurate solution for engineering applications such as belt conveyors, in which the energy dissipated on the rolling contact of idle rollers can, in some cases, be by far the most important contribution to their energy consumption.

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Topology optimization of elastic contact problems using B-spline parameterization

Structural and Multidisciplinary Optimization ◽

10.1007/s00158-020-02837-4 ◽

2021 ◽

Vol 63 (4) ◽

pp. 1669-1686

Author(s):

Jiajia Li ◽

Weihong Zhang ◽

Cao Niu ◽

Tong Gao

Keyword(s):

Topology Optimization ◽

Contact Problems ◽

Elastic Contact ◽

B Spline

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A Unified Abaqus Implementation of the Phase Field Fracture Method Using Only a User Material Subroutine

Materials ◽

10.3390/ma14081913 ◽

2021 ◽

Vol 14 (8) ◽

pp. 1913

Author(s):

Yousef Navidtehrani ◽

Covadonga Betegón ◽

Emilio Martínez-Pañeda

Keyword(s):

Phase Field ◽

Crack Nucleation ◽

Crack Density ◽

Contact Problems ◽

Element Mesh ◽

Robust Implementation ◽

Current Implementation ◽

User Material Subroutine ◽

Complex Crack ◽

Monolithic Solution

We present a simple and robust implementation of the phase field fracture method in Abaqus. Unlike previous works, only a user material (UMAT) subroutine is used. This is achieved by exploiting the analogy between the phase field balance equation and heat transfer, which avoids the need for a user element mesh and enables taking advantage of Abaqus’ in-built features. A unified theoretical framework and its implementation are presented, suitable for any arbitrary choice of crack density function and fracture driving force. Specifically, the framework is exemplified with the so-called AT1, AT2 and phase field-cohesive zone models (PF-CZM). Both staggered and monolithic solution schemes are handled. We demonstrate the potential and robustness of this new implementation by addressing several paradigmatic 2D and 3D boundary value problems. The numerical examples show how the current implementation can be used to reproduce numerical and experimental results from the literature, and efficiently capture advanced features such as complex crack trajectories, crack nucleation from arbitrary sites and contact problems. The code developed is made freely available.

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Elastoplastic Frictional Contact Study on Interference Fits of Compressor

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.211-212.535 ◽

2011 ◽

Vol 211-212 ◽

pp. 535-539

Author(s):

Ai Hua Liao

Keyword(s):

Stress Distribution ◽

Contact Stress ◽

Frictional Contact ◽

Contact Problems ◽

Boundary Problems ◽

Interference Fit ◽

Parametric Variational Principle ◽

Design And Manufacturing ◽

Contact Stress Distribution ◽

Fit Tolerance

The impeller mounted onto the compressor shaft assembly via interference fit is one of the key components of a centrifugal compressor stage. A suitable fit tolerance needs to be considered in the structural design. A locomotive-type turbocharger compressor with 24 blades under combined centrifugal and interference-fit loading was considered in the numerical analysis. The FE parametric quadratic programming (PQP) method which was developed based on the parametric variational principle (PVP) was used for the analysis of stress distribution of 3D elastoplastic frictional contact of impeller-shaft sleeve-shaft. The solution of elastoplastic frictional contact problems belongs to the unspecified boundary problems where the interaction between two kinds of nonlinearities should occur. The effect of fit tolerance, rotational speed and the contact stress distribution on the contact stress was discussed in detail in the numerical computation. The study play a referenced role in deciding the proper fit tolerance and improving design and manufacturing technology of compressor impellers.

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