This paper describes modern techniques used to solve contact problems within Computational Mechanics. On the basis of a continuum description of contact, the mathematical structure of the contact formulation for finite element methods is derived. Emphasis is also placed on the constitutive behavior at the contact interface for normal and tangential (frictional) contact. Furthermore, different discretization schemes currently applied to solve engineering problems are formulated for small and finite strain problems. These include isoparametric interpolations, node-to-segment discretizations and also mortar and Nitsche techniques. Furthermore, several algorithms related to spatial contact search and fulfillment of the inequality constraints at the contact interface are discussed. Here, especially the penalty and Lagrange multiplier schemes are considered and also SQP- and linear-programming methods are reviewed.


Keywords:

contact mechanics;
friction;
penalty method;
Lagrange multiplier method;
contact algorithms;
finite element method;
finite deformations;
discretization methods

Computational Contact Mechanics

Vibration based condition monitoring refers to the use of in situ non-destructive sensing and analysis of system characteristics –in the time, frequency or modal domains –for the purpose of detecting changes, which may indicate damage or degradation. In the field of civil engineering, monitoring systems have the potential to facilitate the more economical management and maintenance of modern infrastructure. This paper reviews the state of the art in vibration based condition monitoring with particular emphasis on structural engineering applications.

Vibration Based Condition Monitoring: A Review:

A review of techniques, advances and outstanding issues in numerical modelling for rock mechanics and rock engineering

Multi-scale computational homogenization: Trends and challenges

1 Formulation of the equations of motion 2 Element energy functions 3 Introduction to the finite element displacement method 4 In-plane vibration of plates 5 Vibration of solids 6 Flexural vibration of plates 7 Vibration of stiffened plates and folded plate structures 8 Vibration of shells 9 Vibration of laminated plates and shells 10 Hierarchical finite element method 11 Analysis of free vibration 12 Forced response 13 Forced response II 14 Computer analysis technique

Introduction to finite element vibration analysis

Failure criteria for quasi-brittle materials are considered in the context of a lattice-type modelling framework. The criteria are implemented and assessed in macro-scale lattice-type models realised through bonded, linked particle assemblies constructed in a DEM framework. Several simple strategies consider failure of individual lattice elements based either on the local conditions at link elements or on the 'homogenized' conditions at an associated continuum point, with both elastic-brittle and elastic- softening plasticity models employed. In spite of observed solution noise, model performance in coarse, macro-scale triangular lattice-type assemblies supports the importance of including both softening and homogenized failure criteria in order to objectively reproduce softening behaviour of an equivalent continuum.

Failure criteria for quasi-brittle materials in lattice-type models

. Mudflows regularly generate significant human and property losses. Analyzing mudflows is important to assess the risks and to delimit vulnerable areas where mitigation measures are required. The smoothed-particle hydrodynamics (SPH) model adopted here considers, in two phases, a granular skeleton with voids filled with either water or mud. The SPH depth-integrated numerical model (Pastor et al., 2009a) used for the present simulations is a 2-D model capable of predicting the runout distance, flow velocity, deposition pattern and the final volume of mudflows. It is based on mathematical and rheological models. In this study, the main characteristics of mudflow processes that have emerged in the past (1908) in the area downstream of the Grohovo landslide are examined, and the more relevant parameters and attributes describing the mudflow are presented. Principal equations that form the basis of the SPH depth-integrated model are reviewed and applied to analyze the Grohovo landslide and the propagation of the mudflow wave downstream of the landslide. Based on the SPH method, the runout distance, quantities of the deposited materials and the velocity of mudflow progression which occurred in the past at the observed area are analyzed and qualitatively compared to the recorded consequences of the actual event. Within the SPH simulation, the Newtonian rheological model in the turbulent flow regime and the Bingham rheological model were adopted and a comparison was made of the application of the Egashira and Hungr erosion law.

/pdf/a-model-of-mudflow-propagation-downstream-from-the-grohovo-1i1qn3l5v1.pdf

A model of mudflow propagation downstream from the Grohovo landslide near the city of Rijeka (Croatia)

https://eprints.ncl.ac.uk/file_store/production/197268/7864E512-A718-4851-A6BF-8B5E4D2C2E3E.pdf

Fully coupled, hygro-thermo-mechanical sensitivity analysis of a pre-stressed concrete pressure vessel

A single rigid prismatic block is analysed for free rocking behaviour without slipping and jumping A numerical procedure based on a precise contact detection is developed and tested An extensive experimental study of free rocking for blocks of different slenderness and size is conducted, with the emphasis on the post-impact behaviour and energy-loss mechanism in the existing impact models The experiments conducted strongly support the definition of the restitution coefficient proposed by Kalliontzis et al A method is proposed to determine the extra parameter present in this model

/pdf/analysis-of-restitution-in-rocking-of-single-rigid-blocks-54rrrr2cai.pdf

Analysis of restitution in rocking of single rigid blocks

https://repository.tudelft.nl/islandora/object/uuid%3A98a39b24-9724-4016-8726-e029b5954037/datastream/OBJ/download

Nenad Bićanić

Papers

Failure criteria for quasi-brittle materials in lattice-type models

A model of mudflow propagation downstream from the Grohovo landslide near the city of Rijeka (Croatia)

Fully coupled, hygro-thermo-mechanical sensitivity analysis of a pre-stressed concrete pressure vessel

Analysis of restitution in rocking of single rigid blocks

A note on singularity indicators for Mohr-Coulomb type yield criteria