Objektno orijentirani pristup metodi konačnih elemenata

Metoda konačnih elemenata je jedna od važnijih numeričkih metoda za rješavanje problema u inženjerstvu poput strukturne analize objekata. Korisnost metode može sve vidjeti po količini alata koji su razvijeni za nju te po tome što je standard u industrijama poput zrakoplovne i automobilske. Cilj ovog diplomskog rada bio je predstaviti OOFEM (Object Oriented Finite Element Method), jedan takav alat i strukturu njegovog otvorenog koda tako da se budući korisnici mogu lakše snaći u njegovom korištenju, a posebice ako im se ukaže potreba za nadogradnjom i implementacijom novih funkcionalnosti. U opisu OOFEM-a poseban naglasak stavljen je na strukturnu analizu te konačne elemente i materijale potrebne koje strukturna analiza zahtjeva poput greda i šipki u dvodimenzionalnom sustavu analize. Središnji dio rada je opis korištenja OOFEM-a putem njegovog sučelja za korištenje iz programskog jezika Python. Osim generalnih informacija što se sve i kako može koristiti putem Pythona, priloženo je i nekoliko primjera te je čak i ukratko opisan postupak kako je izrađeno sučelje iz C++-a tako da se može koristiti u Pythonu. Motivacija iza toga je ta što nisu sve značajke izložene putem Python sučelja, te se ukratko pokazuje kako bi se mogle izložiti nove funkcionalnosti u slučaju potrebe.The finite element method is one of the most important numerical methods for solving engineering problems such as structural analysis of objects. The usefulness of the method can be seen by the amount of tools developed for it and by the fact that it became standard in industries such as aviation and automotive. The aim of this thesis was to present OOFEM (Object Oriented Finite Element Method), enabling future users to use it more easily, especially if they need to upgrade existing or implement new functionalities. In the description of OOFEM, a special emphasis was placed on the structural analysis method and finite elements and materials needed for it as beams and trusses in two-dimensional analysis. The central part of the thesis describes the use of OOFEM through its interface for use in the Python programming language. In addition to general information about what and how to use it through Python, a few examples are included, and a brief description of how a C++ interface is made so that it can be used in Python. The motivation behind it is that not all features are exposed through Python interface, so there is brief introduction how new functionalities could be exposed if necessary

Object oriented design of a thermo-mechanical FEM code

An object oriented design is presented for a computer program that can perform\ud thermo-mechanically coupled analyzes. The target of the design is a \ud exible and robust\ud computer program. It should be easy to adapt and extend, re-using existing code, without\ud interfering with already established algorithms.\ud The program uses publicly available toolkits that are currently emerging as C++ pack-\ud ages. First of all the Standard C++ Library (formerly Standard Template Library) is\ud used for packing items in container classes. Secondly the matrix and vector operations\ud are derived from the Template Numerical Toolkit (TNT) and �nally (not essentially for\ud the numerical part) a graphical user interface is made, based on the wxWindows package,\ud that can generate a GUI for Motif and MS-Windows with the same code.\ud Attention is given to the design of classes such as speci�c elements and material classes\ud based on more general classes. A hierarchy of classes is constructed where general behavior\ud is put high in the hierarchy and speci�c behavior low. The choice between inheritance and\ud aggregation is made at several levels

Parallelization of an object-oriented FEM dynamics code: influence of the strategies on the Speedup

This paper presents an implementation in C++ of an explicit parallel finite element code dedicated to the simulation of impacts. We first present a brief overview of the kinematics and the explicit integration scheme with details concerning some particular points. Then we present the OpenMP parallelization toolkit used in order to parallelize our FEM code, and we focus on how the parallelization of the DynELA FEM code has been conducted for a shared memory system using OpenMP. Some examples are then presented to demonstrate the efficiency and accuracy of the proposed implementations concerning the Speedup of the code. Finally, an impact simulation application is presented and results are compared with the ones obtained by the commercial Abaqus explicit FEM code

Modelling and simulation framework for reactive transport of organic contaminants in bed-sediments using a pure java object - oriented paradigm

Numerical modelling and simulation of organic contaminant reactive transport in the environment is being increasingly relied upon for a wide range of tasks associated with risk-based decision-making, such as prediction of contaminant profiles, optimisation of remediation methods, and monitoring of changes resulting from an implemented remediation scheme. The lack of integration of multiple mechanistic models to a single modelling framework, however, has prevented the field of reactive transport modelling in bed-sediments from developing a cohesive understanding of contaminant fate and behaviour in the aquatic sediment environment. This paper will investigate the problems involved in the model integration process, discuss modelling and software development approaches, and present preliminary results from use of CORETRANS, a predictive modelling framework that simulates 1-dimensional organic contaminant reaction and transport in bed-sediments

The development of finite element software for creep deformation and damage analysis of weldment

This paper presents the development of finite element software for creep deformation and damage analysis of weldment. The development and benchmark test of the software under plane stress, plane strain, axisymmetric, and 3 dimensional cases were reported in previous work [1]. This paper primarily consists of two parts: 1) the structure of the new FE software and the existing FE library applied in obtaining such computational tool via an approach for stress and field variable updating; 2) the development and validation of stress update; and 3) the development of validation of multi-material zones version. This paper contributes to the computational creep damage mechanics in general and particular to the design and the development of finite element software for creep damage analysis of multi-material zone

PROSET — A Language for Prototyping with Sets

We discuss the prototyping language PROSET(Prototyping with Sets) as a language for experimental and evolutionary prototyping, focusing its attention on algorithm design. Some of PROSET’s features include generative communication, flexible exception handling and the integration of persistence. A discussion of some issues pertaining to the compiler and the programming environment conclude the pape

Towards Practical Graph-Based Verification for an Object-Oriented Concurrency Model

To harness the power of multi-core and distributed platforms, and to make the development of concurrent software more accessible to software engineers, different object-oriented concurrency models such as SCOOP have been proposed. Despite the practical importance of analysing SCOOP programs, there are currently no general verification approaches that operate directly on program code without additional annotations. One reason for this is the multitude of partially conflicting semantic formalisations for SCOOP (either in theory or by-implementation). Here, we propose a simple graph transformation system (GTS) based run-time semantics for SCOOP that grasps the most common features of all known semantics of the language. This run-time model is implemented in the state-of-the-art GTS tool GROOVE, which allows us to simulate, analyse, and verify a subset of SCOOP programs with respect to deadlocks and other behavioural properties. Besides proposing the first approach to verify SCOOP programs by automatic translation to GTS, we also highlight our experiences of applying GTS (and especially GROOVE) for specifying semantics in the form of a run-time model, which should be transferable to GTS models for other concurrent languages and libraries.Comment: In Proceedings GaM 2015, arXiv:1504.0244