Object-oriented finite element analysis and programming in VC++

This chapter shows, through the example of the addition of a plate and shell element to freeware FEM-object, an object-oriented (C++) finite element program, how object-oriented approaches, as opposed to procedural approaches, make finite element codes more compact, more modular, and versatile but mainly more easily expandable, in order to improve the continuity and the compatibility between software of research and industrial software. The fundamental traits of object-oriented programming are first briefly reviewed, and it is shown how such an approach simplifies the coding process. Then, the isotropic shell and orthotropic plate formulations used are given and the discretized equations developed. Finally, the necessary additions to the FEM-object code are reviewed. Numerical examples using the newly created plate membrane plate element are shown.

Object-oriented programming (OOP) has been the most important development method, especially for huge and complicated program systems, since OOP can overcome structural complexity of code, strong coupling among modules and poor maintenance shortcomings in traditional structural programming. Since B.W.R.Forde applied OOP to Finite Element (FE) firstly in 1990, the research in this field has not been stopped. Scholars have taken many positive and useful attempts on study of OOP in FE programming from different aspects. The state of the art of OOP in FE and current development has been reviewed, and the key problems in the OOP FEM fields thus are pointed out, thus prospects of OOP in FE code design are put forward.

An understanding of the overall porous copper behavior is developed through the combination of real data from microstructures and the fundamental material characteristics of the constitutive phases. Captured morphological images, using the Nano-CT are utilized to generate the geometric information. Object-oriented finite element (OOF) analysis is quite a novel numerical approach to incorporate morphological images, acquired from scanning electron microscopy into 2-D finite element modeling. This paper seeks to investigate the porosities using two methods (Archimedes principle and Nano-CT) and then to introduce an image-based extended OOF modeling technique based on mapping the real microstructures of porous copper and gage its ability to predict the elastic moduli and evaluate the deformation mechanism resulting from the porous copper. Dissolution sintering technique was used by mixing Cu powders with NaCl in the volume ratio of 1:1 and 1:3 adding polyvinyl alcohol solution as a binder with NaCl as the space holder. The green form was pressed at 375 MPa using a four-column hydraulic lab press. The NaCl was leached out in hot water at 70 °C and then sintered to a temperature of 850 °C. Porosity values were determined from density measurements to give the porosity values of 42.2 and 45.71 % for volume ratio of 1:1 and 1:3, respectively. The material properties were obtained from the tests and compared to previous literature. Very good agreement has been shown, establishing the viability of this kind of morphology-based numerical approach.

For large-scale finite element analysis, using a numerical method to reduce the problem size is a standard strategy to analyze a problem efficiently. For the analysis with reduction, the most time-consuming process is reducing the degrees of freedom, not solving the global sparse system in the standard analysis. Therefore, improving the efficiency of the reduction process is the key to further speedup the analyses of large-scale problems. Nonlinear analysis is much more computationally intensive than linear elastic analysis. There is a need to investigate a more efficient reduction method for nonlinear problems. This paper presents a new domain decomposition method for nonlinear substructures, which can greatly reduce the analyses time for large-scale nonlinear problems. In the proposed method, the nonlinear behavior of a substructure is updated by adding correcting modes, instead of totally repeating the whole reduction process. The efficiency can be further improved by cooperating with a parallel processing technique. The proposed method was implemented in a parallel object-oriented finite element analysis program, and its performance and accuracy were verified on various examples.

Object-oriented finite element programming: III. An efficient implementation in C++

The acquisition of problem-solving and programming skills in the era of knowledge society seems to be particularly important. Due to the intrinsic difficulty of acquiring such skills various educational tools have been developed. Unfortunately, most of these tools are not utilized. In this paper we present the programming microworlds Karel and objectKarel that support the procedural-imperative and Object-Oriented Programming (OOP) techniques and can be used for supporting the teaching and learning of programming in various learning contexts and audiences. The paper focuses on presenting the pedagogical features that are common to both environments and mainly on presenting the potential uses of these environments.KeywordsKnowledge SocietyProgramming SkillPedagogical FeatureEducational SoftwareProgramming ConceptThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Automation software systems usually implement the IEC 61131-3 and IEC 61499 standards. Nowadays, these applications request, among others, reusability, flexibility, reliability, and modularity via both standards. These characteristics can be achieved by a traditional paradigm called Object-Oriented Programming (OOP). OOP is an older method that applied with various programming languages to generate a replicable style of programming, i.e., code composed by Functions, Methods, etc. A well-defined programming method makes the code understandable for programmers. OOP defines the reusability, accessibility, adaptability, and robustness of software programs. It means that using gradual methods gained experience improves the quality of programs and simplifies their organization. OOP also increases the security of applications from its core features, i.e., Abstraction, Instantiation, Encapsulation, Polymorphism, and others. Therefore, OOP has been applied and discussed for both standards; however, OOP’s complexity and implementation using these IEC standards have not been compared yet. This work proposes the typical application of the Function Block (FB) to define classes and objects for industrial automation systems based on OOP. We implement one particular case of study for both standards. The FB employments are evaluated in order to compare OOP applicability and advantages of each standard. Adapting automation software regarding new industry requirements implies greater modularity. Code programmed by OOP generates abstractions levels which improve the design and make the software application in maintenance more comfortable to read and more adaptable to future extensions. This research shows how both standards (their latest updates) address OOP. Object-oriented programs in the field of automation engineering face another paradigm shift that impacts the methods used to program control systems. OOP would facilitate the design patterns implementations, which are a reusable understanding of common problems.

Object-oriented technology, including object-oriented analysis (OOA), object-oriented design (OOD), and object-oriented programming (OOP), is a new promising approach to developing software systems to reduce software costs and to increase software extensibility, flexibility, and reusability. Software metrics are widely used to measure software complexity and assure software correctness. This paper proposes a metric to measure object-oriented software. Also, an important factor called URIs, is conducted to build the metric. This approach describes a graph-theoretical method for measuring the complexity of the class hierarchy. The proposed metric shows that inheritance has a close relation with object-oriented software complexity and reveals that misuse of repeated (multiple) inheritance will increase software complexity and be prone to implicit software errors. >

Describes the metamodelling approach towards evaluating the fit of object-oriented analysis and design (OOAD) methodologies to object-oriented programming (OOP) languages. Metamodelling has been applied successfully to evaluate and integrate OOAD methodologies. In this paper, the use of metamodelling is extended to describe OOP languages. This paper describes an approach to use OOAD and OOP metamodels to analyse the fit of OOAD methods to OOP languages. The approach is illustrated by evaluating the fit of Booch OOAD on Smalltalk, Eiffel and C++. It is concluded that using metamodelling an objective assessment of the match of an OOAD methodology to an OOP language can be made.

Software metrics is a necessary step for software reliability and quality, and software metrics of traditional procedure-oriented programming are fairly mature and have various methodologies and tools available for use. Object-oriented programming has recently became popular. However, traditional procedure-oriented software metrics are not appropriate for the development of object-oriented software. Some research into object-oriented software metrics has been proposed, but these articles focus on only one metric that measures a specific characteristic of the object-oriented software. The authors propose a new metric methodology, the data scope complexity, for object-oriented software based on the data scope of a program. The data scope complexity can show complexities of multiple features of object-oriented programming at the same time. They also quantify and compare object-oriented programming with procedure-oriented programming.

The object-oriented programming is widely used in different fields of finite element analysis (FEA). The commonly used object-oriented codes were almost written by C++. Due to the inability to automatically manage memory and the lack of gigantic standard library and a third-party library for C++, building matrix classes are needed and a strong programming ability for program developers is also necessary. The conventional FEM method still has many disadvantages such as poor accuracy, hard stiffness matrix, mesh dependence and lack of upper bound solution. The smoothed FEM (S-FEM) method proposed by Liu et al. can efficiently overcome these disadvantages and is therefore widely used in FEA. In this work, the elastic-plastic CS-FEM method is extended and implemented using Python programming based on the framework proposed [H. Li and Y. Xiao, Implementation and numerical simulation on object-oriented elastic-plastic finite element method based on Python, J. Syst. Simul. 36(5) (2024) 1107–1117] The resulting object-oriented elastic-plastic CS-FEM framework is then applied to FEA of elastic-plastic mechanics problems. The correctness of the resulting framework and the high computational accuracy and good mesh adaptability of CS-FEM models have been verified by comparing the corresponding results with an analytical solution or ABAQUS results. The object-oriented elastic-plastic CS-FEM framework provides a more efficient and adaptable approach to FEA, and can also overcome many limitations of the conventional FEM method and C++ programming. The use of Python and the CS-FEM method offers improved computational accuracy, mesh adaptability and development efficiency, and this will make it a valuable tool for solving practical problems in mechanics and engineering.

Hardware reconfiguration of Transputer networks for distributed object-oriented programming

: Object-oriented programming techniques have become a vital part of modern software engineering. Most large new commercial software products are designed today using objects oriented principles along with supporting development environments and tools. Such methodology is particularly appealing for parallel computing, where there is great need for approaches capable of simplifying the programming task and producing high quality software more quickly. In this project we have carried out research that will lead to a new parallel object-oriented language based on C++. The new language, C++-Linda, is a novel combination of the most widely used object-oriented language and a successful environment for parallel computing that supports a virtual shared memory model for process interaction. This combination is an especially appropriate one because Linda's memory model is naturally object-oriented, enabling a seamless design that is completely consistent with object-oriented methodology. In this Phase I project, we have carried out research to understand the basic issues underlying parallel object-oriented languages, and we have created a preliminary design for C++-Linda. In a future Phase II project, we plan to develop a prototype implementation that will serve as a guide for eventual commercialization. Parallel computing, Programming languages, Object-oriented languages, Linda, C++-Linda, (C++).

Adherence of plasma-sprayed thermal barrier coatings (TBC's) during deposition is strongly dependent on a rough metallic bond-coat surface topology. However, the resultant interfacial asperities modify the residual stresses that develop in the coating system due to thermal expansion differences, and other misfit strains, and generate stresses that can induce progressive fracture and eventual spallation of the ceramic coating. For a flat interface, the principal residual stress is parallel to the interface, as the stress normal to the interface is zero. However, the residual stress normal to the interface becomes non-zero, when the interface has the required interlocking morphology. In the present study, an actual microstructure of a plasma-sprayed TBC system was numerically simulated and analyzed with a recently developed, object-oriented finite element analysis program, OOF, to give an estimate of the localized residual stresses in a TBC system. Additionally, model TBC microstructures were examined to evaluate the manner in which the topology of interfacial asperities influences residual stresses. Results are present for several scenarios of modifying interfacial roughness.

This article describes an introductory object-oriented finite element program for static and dynamic nonlinear applications. This work can be considered as an extension of the original FEM_Object environment dealing with linear elasticity [1] and nonlinearity [2]. Mainly the static aspects are discussed in this paper. Interested readers will find a detailed discussion of the object-oriented approach applied to finite element programming in [15-18] and also in [7-8] and references therein. Our ambition, in this paper, is limited to a presentation of an introductory object-oriented finite element package for nonlinear analysis. Our goal is to make a starting package available to newcomers to the object-oriented approach and to provide an answer to the large number of demands for such a program received in recent time. In the first part of the paper, a brief recall of the basics of finite element modeling applied to continuum mechanics is given. Von Mises plasticity including isotropic and kinematic hardening, which is used as model problem, is described. This first part also presents an overview of the main features of the object-oriented approach. In the second part of this paper, classes and associated tasks forming the kernel of the code are described in detail. A hierarchy of classes is proposed and discussed; it provides an immediate overview of the program's capabilities. Finally interactions between classes are explained and numerical examples illustrate the approach.