Please read the abstract in the section 00front of this document / Dissertation (MEng (Mechanical Engineering))--University of Pretoria, 2007. / Mechanical and Aeronautical Engineering / unrestricted

This thesis presents the results of a theoretical and experimental study of the lateral buckling of straight beams of rectangular cross-section resting on columns, a type of structure commonly found in the roofing system of multi-bayed buildings. The structure is analyzed as a simply supported beam, uniformly loaded, restrained at one end against longitudinal torsion and resting near the other end on a flexible column which may provide various torsional and lateral restraints. Beyond the column is a cantilevered projection of various lengths and loads. The entire top edge of the beam is considered as fastened to a continuous decking which restrains it against horizontal displacement but permits free rotation about this edge. The method of solution of the theoretical lateral buckling load is by using a computer program to calculate the structure stiffness matrix's determinant at increasing load levels, and a plot of the determinant versus load level yields the critical load (at determinant equals zero). This theoretical approach is verified by model experiments in the laboratory. Design curves and equations are produced incorporating the usual flexural beam and axially loaded column strength concepts, with lateral buckling considerations. Recommended design code procedures are forwarded based on these curves which would permit more economical use of deep beams. Included in the thesis is the computer program listing used in the solution technique. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Master of Engineering

No description available.

Any structural analysis which gives stresses and displacements for some predefined structure is governed by some physical domain of loading, geometry and boundary conditions. Let this domain be called the structures "problem space." In applying finite element analysis, the solution to any one problem space may be one of many admissible solutions all of which satisfy some given set of boundary conditions. Admissibility is determined by the stated problem with its boundary conditions along with computer storage capacity considerations. Obtaining the most exact approximate solutions is one of major concern to insure adequate results. This problem has been approached from a number of viewpoints [4-9] all of which employ some version of minimum potential energy [5, 10]. This report is a study of current approaches to this problem and their effect on finite element grid optimizations. Selected optimizations [4-9] are shown to be effective in producing better solutions but it is noted that the implementation of these optimizations may be difficult. To survey the situation two fixed problem spaces of a tapered beam and a cantilever beam are chosen for investigation. Conclusions based on this study display that optimizations methods applied to a finite element model give an optimum space arrangement that is a function of the selected element geometry and displacement function. When changes in the element geometry are introduced a new optimum results. Comparing test problem results leads to some speculation employing uniform strain energy as a better guide to "first guess" grid arrangement and a recommendation for further investigation in this direction.

Thesis (MScEng)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: AP230 of STEP is an application protocol for structural steel-framed buildings. Product data relating to steel structures is represented in a model that captures analysis, design and manufacturing views. The information requirements described in AP230 were analysed with the purpose of identifying a subset of entities that are essential for the description of simple industrial steel frames with the view to being able to describe the structural concept, and to perform the structural analysis and design of such structures. Having identified the essential entities, a relational database model for these entities was developed. Planning, analysis and design applications will use the database to collaboratively exchange data relating to the structure. The comprehensiveness of the database model was investigated by mapping a simple industrial frame to the database model. Access to the database is provided by a set of classes called the database representative classes. The data-representatives are instances that have the same selection identifiers and attributes as corresponding information units in the database. The datarepresentatives' primary tasks are to store themselves in the database and to retrieve their state from the database. A graphical user interface application, programmed in Java, used for the description of the structural concept with the capacity of storing the concept in the database and retrieving it again through the use of the database representative classes was also created as part of this project. / AFRIKAANSE OPSOMMING: AP230 van STEP is 'n toepassingsprotokol wat staal raamwerke beskryf. Die produkdata ter beskrywing van staal strukture word saamgevat in 'n model wat analise, ontwerp en vervaardigings oogmerke in aanmerking neem. Die informasie vereistes, soos beskryf in AP230, is geanaliseer om 'n subset van entiteite te identifiseer wat noodsaaklik is vir die beskrywing van 'n eenvoudige nywerheidsstruktuur om die strukturele konsep te beskryf en om die struktuur te analiseer en te ontwerp. Nadat die essensiële entiteite geïdentifiseer is, is 'n relasionele databasismodel van die entiteite geskep. Beplanning, analise en ontwerptoepassings maak van die databasis gebruik om kollaboratief data oor strukture uit te ruil. Die omvattenheid van die databasis-model is ondersoek deur 'n eenvoudige nywerheidsstruktuur daarop afte beeld. Toegang tot die databasis word verskaf deur 'n groep Java klasse wat bekend staan as die verteenwoordigende databasis klasse. Hierdie databasis-verteenwoordigers is instansies met dieselfde identifikasie eienskappe as die ooreenkomstige informasie eenhede in die databasis. Die hoofdoel van die databasis-verteenwoordigers is om hulself in die databasis te stoor asook om hul rang weer vanuit die databasis te verkry. 'n Grafiese gebruikerskoppelvlak, geprogrammeer in Java, is ontwikkel. Die koppelvlak word gebruik om die strukturele konsep te beskryf, dit te stoor na die databasis en om dit weer, met behulp van die databasis-verteenwoordigers, uit die databasis te haal.

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Civil Engineering / Doctoral / Doctor of Philosophy

No description available.