This report aims to covers the conduction of a final thesis project for the University of Skövde in collaboration with J.Design studio (Stockholm). The purpose of this project is applying and evaluating CAD and different tools related to the field of 3D CAD within design and product development phases. This has been achieved by the development of two pieces of furniture from a defined line of products stated by existing clients of J.Design. The initial phase of the project was knowing the design limitations from both clients and their stakeholders. Once these limitations were known, a pre-study phase where 3D CAD modelling was set as the key tool for the research was done. This research identified related tools with CAD that are applied during the development design phase. Starting the development of the two case studies, the user needs’ phase was the first step in the process, followed by a benchmarking study, an ergonomics study, and finally, setting these requirements into a requirement list. Then, the design development phase took place, covering initial sketches until the detailed final solutions. As a final step, the use of the identified tools was evaluated and analysed based on the experience from the two case studies of this thesis project. From this evaluation came the conclusion that these tools need to take part in the design phase in a certain moment depending on the level of development, and as the level of sophistication of the tool increases, the information and detail provided are also higher.

Proplate, a world leading company, is expert on volume-based cutting and machining of both ordinary steel as well as stainless steel. One of Proplate’s mayor products is tension bars, which is a component made to balance high forces and give stability to structures such as cranes, buildings, bridges and much more. Proplate builds their tension bars in different high strength steel materials, purchased from SSAB, and sells them worldwide. Proplate would like to market themselves better and wishes to produce a catalogue for the maximum load that can be applied to their tension bars, as competitors Pretec and Macalloy, already have for their tension bars. The purpose of the project has been to investigate the tension bars and the maximum load they can withstand before failure. The tension bars have been modeled in the CAD-program Creo Parametric, and then sent to the finite element method program ABAQUS to analyze their structural strength. Three different types of tension bars, and a fourth tension bar (called the walnut-strap) used as a connecting element between some of the tension bars, were investigated. They were modeled with sprints, to hold several tension bars together, and with a construction called loader, to simplify the model load application step. The three different types of tension bars have been analyzed as individual and also when connected to other tension bars. Some tension bars could be directly connected to each other with sprints, and some used the walnut-strap to connect other tension bars to each other. The project was limited to fatigue analyses, which is an important factor to control. This could instead be a great continuation of the project. The results from the strength analyses show that the stress is higher at the surfaces around the hole at the end of each tension bar, and the maximum load the tension bars can withstand depends on this area. The length, thickness and orientation of the tension bar has been varied, and the maximum load that each model can withstand has been listed. The length and direction of the tension bars did not influence the result for singular tension bars, but the thickness did. Both the length and the thickness of the tension bars did influence the result when multiple tension bars where connected to each other. Tables have been derived which shows the absolute maximum load that the tension bars can withstand. Proplate can use the tables in their catalogue, and they can also put a safety factor on the models to make them safer. Another part of the study was to investigate advantages and disadvantages with if the sprints, the connecting element between the tension bars, were replaced with screws instead. The result describes the yield strength needed for the screws and how the structures would behave compared to the current structure. A larger investigation into the effect of using screws may be one way to continue the work after this project, together with other investigations of, for instance, the use of compression bars. / Proplate är ett världsledande företag, som är experter på volymbaserad skärning och tillverkning i både vanligt stål såväl som rostfritt stål. En av Proplates huvudprodukter är deras dragstag, som är en komponent gjord för att balansera stora krafter och tillbringa stabilitet till strukturer, exempelvis lyftkranar, byggnader, broar med mera. Proplate bygger sina dragstag med hjälp av olika typer av höghållfasta stålsorter, köpta från SSAB, och säljer sedan produkterna över hela världen. Proplate skulle vilja marknadsföra sig bättre och önskar att ta fram en katalog över den maximala kraften som kan appliceras på dragstagen, vilket konkurrenter som Macalloy och Pretec redan har för sina dragstag. Syftet med projektet är att undersöka dragstagen och den maximala kraften som dragstagen klarar av innan de går sönder. Dragstagen har modellerats upp i CAD-programmet Creo Parametric, och sedan skickats till finita-elementmetodsprogrammet ABAQUS för hållfasthetsanalyser. Tre olika typer av dragstag, och en fjärde variant (kallad valnöts-staget) som använts som ett sammankopplande element mellan olika typer av dragstagen, har undersökts. De har modellerats tillsammans med sprintar, för att hålla samman flera dragstag, och en konstruktion vid namn loader, som ska förenkla kraftapplikationssteget i analyserna. De tre olika typerna av dragstag har analyserats individuellt och sammankopplade till andra dragstag samtidigt. Några av dragstagen kunde direkt sammankopplas till andra dragstag med hjälp av sprintar, men andra behövde valnöts-staget för att sammankoppla dragstagen till varandra. Projektet var avgränsat så att utmattningslaster, vilket är en mycket viktig faktor, inte analyserades. Resultatet från hållfasthetsanalyserna visar att spänningarna i ytan kring ett hål i kanterna av dragstagen blir som störst, och den maximala kraften som dragstagen kan klara av är beroende på denna yta. Dragstagens längd, tjocklek och orientering i rummet har varierat, och den maximala kraften som varje modell kan klara av har tabellerats. Dragstagens längd och riktning i rummet påverkade inte resultatet när individuella dragstag analyserades, men dess tjocklek gjorde det. Både längden och tjockleken av dragstagen påverkade resultatet när flera dragstag blivit sammankopplade till varandra. Tabellerna visar den absolut maximala kraften som dragstagen kan klara av. Proplate kan använda dessa tabeller till deras katalog, och de kan också lägga till en säkerhetsfaktor på modellerna för att göra dem säkrare. En annan del av analyserna var att undersöka fördelarna och nackdelarna om sprintarna, som är det sammankopplande elementet mellan de olika dragstagen, blivit utbytta mot skruvar istället. Resultatet beskriver vilken sträckgräns som skulle behövas för skruvarnas material och hur strukturen skulle bete sig i jämförelse till den nuvarande strukturen. En större undersökning angående effekten med skruvar kan vara en bra fortsättning på arbetet efter detta projekt, tillsammans med andra undersökningar som exempelvis angående användning av tryckstag.

PhD Thesis / Cardiac surgeons rely on simulation training to improve their surgical skills. The focus of this research was on creating a 3D aortic valve model for cardiac surgical skills training. The research was divided into four different stages including CAD model development, tissue testing using surgical tools, aortic valve model manufacturing and model evaluation. First, the development of a patient-specific aortic valve model was carried out. The process involved heavily processing CT scanned data of the aortic valve to extract the geometric information via segmentation. Patient-specific models are critical for pre-operative planning and training. However, those models are not ideal for large volume quantities due to the high production costs and the extensive manual labour required to process the models. Therefore, another approach was chosen to produce a generic model that was more suitable for large volume quantities. The generic aortic valve model was developed using data obtained from the literature. The contribution in this stage was developing the methodology to reverse engineer patient-specific cardiac tissues. Additionally, a generic CAD model of the aortic valve was developed. Second, to select suitable materials for the model, samples from biological tissues and polymers were tested using a surgical tool. The contribution in this stage was documenting the forces and displacements obtained from puncturing and cutting the samples using suturing needles and scalpel blades. Third, the aortic valve model was manufactured using two approaches including AM and casting. The contribution in this stage revolved around the development of several moulds for casting. Finally, evaluation of the model was done via an initial assessment session with surgical residents. Although the model was not evaluated in extensive training sessions, a plan highlighting the important elements to do that was included in this research. Thus, the contribution in this stage was developing the model testing plan. / Thesis / Doctor of Philosophy (PhD) / Typically, surgeons use post-mortem human tissues (cadavers) and animal tissues for surgical skills training. However, those methods can be both expensive and limited in availability. Therefore, other non-biological methods are introduced constantly to provide viable alternatives. Those methods include producing models using 3D printing, virtual reality (VR) simulation and even using household items to create training models. However, to date, there is a lack of highly accurate representation of real tissues (fidelity) of most models for cardiac surgical training. The purpose of this research was to develop and manufacture surgical skill training tools for cardiac surgeons focusing on the aortic valve cardiac tissues. The research was divided into several parts including developing computer models using patient-specific medical imaging, developing a general training model and training models manufacturing. Also, the research included manufacturing materials selection process as well as plans for testing the training models in training sessions.

The topic of this thesis is geometry, its practical usage in architect’s profession (especially its application in computer design and realization of buildings) and its current way of teaching at schools of architecture. The thesis systematically describes geometric objects’ construction and properties, its modelling in CAD systems and examples of its usage in architecture, in some cases including the way of its realization. Geometric objects are systematically organized into chapters about point, curves, surfaces and solids. The outcome of the thesis is a concept of geometry courses modification in the way that they encourage the spatial imagination development instead of “drill” and the gained knowledge is directly useful in architect’s profession. A supplementary research (in appendix) analyses the state-of-the-art of teaching of geometry at selected schools of architecture in Europe and its effect to spatial imagination development. The research was focused at contents and form of the selected geometry courses and its influence to spatial imagination.

This investigation identifies how CAD models of typical automotive body assemblies could be defined to allow a continuous optimisation of the number of iterations required for the final design and the number of variants on the basis of Parametric Associative Design (PAD) and how methodologies for the development of surfaces, parts and assemblies of the automotive body can be represented and structured for a multiple re-use in a collaborative environment of concept phase of a Product Evolution (Formation) Process (PEP). The standardisation of optimised processes and methodologies and the enhanced interaction between all parties involved in product development could lead to improve product quality and reduce development time and hence expenses. The fundamental principles of PAD, the particular methodologies used in automotive body design and the principles of methodical development and design in general are investigated. The role which automotive body engineers play throughout the activities of the PEP is also investigated. The distribution of design work in concept teams of automotive body development and important methodologies for the design of prismatic profile areas is critically analysed. To address the role and distribution of work, 25 group work projects were carried out in cooperation with the automotive industry. Large assemblies of the automotive bodies were developed. The requirements for distributed design work have been identified and improved. The results of the investigation point towards a file based, well structured administration of a concept design, with a zone based approach. The investigation was extended to the process chain of sections, which are used for development of surfaces, parts and assemblies. Important methods were developed, optimised and validated with regard to an update safe re-use of 3D zone based CAD models instead of 2D sections. The thesis presents a thorough description of the research undertaken, details the experimental results and provides a comprehensive analysis of them. Finally it proposes a unique methodology to a zone based approach with a clearly defined process chain of sections for an update-safe re-use of design models.