This thesis discusses a methodology for probabilistic design optimization of aircraft structures subject to a multidisciplinary set of requirements originating from the desire to minimize structural weight while fulfilling the demands for quality, safety, producibility, and affordability. With this design methodology as the framework, a software is developed, which is capable of performing design optimization of metallic built-up beam structures where the material properties, external load, as well as the structural dimensions are treated as probabilistic random variables. The structural and failure analyses are based on analytical and semi-empirical methods whereas the component reliability analysis is based on advanced first-order second moment method. Metrics-based analytical models are used for the manufacturability analysis of individual parts with the total manufacturing cost estimated using models derived from the manufacturing cost / design guide developed by the Battelle¡¯s Columbus Laboratories. The resulting optimization problem is solved using the method of sequential quadratic programming. A wing spar design optimization problem is used as a demonstrative example including a comparison between non-buckling and buckling web design concepts. A sensitivity analysis is performed and the optimization results are used to highlight the tradeoffs among weight, reliability, and manufacturing cost.

This thesis is a continuation of design automation studies within research projects financed by VINNOVA (the Swedish Governmental Agency for Innovation Systems) and Knowledge foundation that contributed to the development of producibility assessment system at a global aerospace products supplier, GKN Aerospace Sweden. A case study was carried at the company on Turbine Rear Structure (TRS) component design of a jet engine with the main objective to evaluate weld producibility assessment tools and to demonstrate system’s performance in multi-disciplinary design environment. The context of this thesis is a set-based product design development where several studies, i.e. thermal, structural, aerodynamic etc. are carried concurrently to gather knowledge between their parameter relations. The thesis contributes to the goal of fully integrated producibility assessment in multi-disciplinary studies to support product development process. The problems encountered during the thesis execution involved systematic analysis setup to extract and verify CAD geometry data, assessment of meaningfulness of producibility indicators, development of semi-automated data post-processing module and relating product design to its manufacturing aspects. Commercial and in-house developed software were used extensively to demonstrate the results of the system with the help of continuous company support to mitigate indispensable bottlenecks along the way. The work has led to systematic improvements, determined assessment limitations and most relevant weld producibility aspects. Collected feedback to evaluate prepared demonstrator showed promising results to support product design decisions considering both performance and producibility.

For many products, the adaptation to customer specifications is essential and requires flexible product design and manufacture while maintaining competitive pricing. Engineering design is often concerned with striking a good balance between product properties, e.g. performance, and the resources required to manufacture and assemble the product. When different courses of action are to be evaluated, even seemingly small changes in customer requirements, product design, and manufacturing properties have to be handled with caution. Small changes can entail products with: low level of conformability with the manufacturing system, highly increased cost, and extended manufacturing lead-time. For most companies, the manufacturing system is a valuable asset that is more or less fixed and only minor adaptations are allowed. This implies that the product design has to be adapted to the manufacturing system to a large extent. Design for producibility (DFP) is the process in which a systematic method is used to reach the required functional properties of the product at the same time as good compliance with the manufacturing system is ensured. The DFP process usually needs to involve several persons simultaneously for the purpose of sharing information and knowledge. For many manufacturing companies, the collaboration between engineering design and production engineering is a critical issue and they have to improve their methods and tools for ensuring and enhancing producibility. This can be achieved by introducing computer-supported design for producibility. The present research is intended to contribute to the development and utilisation of different application systems that can be used as such computer support. The aim is to provide companies with support in application system development and to show how different application systems can be used in a systematic way as means to ensure and enhance producibility. The competitive advantages to gain from introducing computer-supported design for producibility are: product designs with high level of conformability with the production system, shortened manufacturing lead-time, and decreased manufacturing cost. This work contributes to the achievement of these advantages by introducing a framework with principles and models supporting application systems development. Three types of application systems are presented and their practical usefulness is examined, showing practitioners how producibility aspects can be assessed systematically. The main scientific and theoretical contribution of the work comprises: the descriptions concerning how to structure and describe the product and product-related information (manufacturing requirements, costs, process plans and production resources), the foundation of different information models, and the clarification of the models’ interrelationships. This is perceived as a contribution to a better understanding of the domains and how they relate to each other.Design for producibility (DFP) is the process in which a systematic method is used to reach the required functional properties of the product at the same time as good compliance with the manufacturing system is ensured. The DFP process usually needs to involve several persons simultaneously for the purpose of sharing information and knowledge. For many manufacturing companies, the collaboration between engineering design and production engineering is a critical issue and they have to improve their methods and tools for ensuring and enhancing producibility. This can be achieved by introducing computer-supported design for producibility. The present research is intended to contribute to the development and utilisation of different application systems that can be used as such computer support. The aim is to provide companies with support in application system development and to show how different application systems can be used in a systematic way as means to ensure and enhance producibility.

In this thesis, the structural design, structural analysis and producibility analysis of an unmanned aerial vehicle wing were performed. Three different wing models, made of different materials, were designed. The wings were aluminum wing model and composite wing models / made of prepreg and wet lay-up. All wings have the same aerodynamic geometry and structural configuration under the same flight conditions. The structural designs of three wings were done by using Unigraphics NX. The finite element modeling of the wings were built by using MSC Patran package program. After the application of the loads on models, structural analyses were performed by MSC Nastran. Finally, the producibility analysis of prepreg wing model was conducted by using FiberSIM package program. The prepreg wing model was selected as optimum design with studies conducted in the study considering weight, producibility, cruise and gust stress and displacement conditions.

Product development is affected by uncertainties due to changing customer requirements, changing regulations, technological developments, long lead times, high product complexities, and geopolitical issues. Automation, increased flexibility of production, and reduced lead times are drivers that allow product development to be competitive in this scenario. Design engineers should be aware of production capabilities to facilitate early producibility assessments and to avoid late changes. Production preparation is identified as an important activity in the product development process, whereby the producibility of a product is assessed. In this thesis, the current state of production preparation during product development is investigated and a method is introduced supporting production preparation using production requirements. The work was carried out using the design research methodology framework and comprised four studies based on the four steps of the framework. The research clarification and descriptive study 1 phases aimed at developing understanding and were done by means of data collection at the companies through interviews and document studies. The next two steps were prescriptive study and descriptive study 2, which aimed at developing and evaluating the support. This was done through observation, workshops, and solution development. The production preparation process is supported by Design for Manufacturing and Assembly, failure mode and effects analysis, lesson-learnt documents, and computer-aided design, and the efficiency of the process is dependent on individual skills and knowledge. Tools to support common understanding, remove ambiguity in requirements, and enable collaboration between design and production engineers are needed. The developed method allows for the identification, definition, structuring, and sharing of production requirements, aligning with varying maturities of product and production systems during product development. This helps improve the collaboration between design and production engineers for production preparation.

No description available.

This projects aims to develop design automation in product development. Design automation causes increase in producibility and decrease in product cost and manufacturing lead time. The study at hand is proposed to provide a new method and to introduce procedure to the design of wiring pattern for a car seat heater for Kongsberg Automotive, KA. KA is a Norwegian company and a global provider of engineering, design, and manufacture for seat comfort, driver and motion control systems, fluid assemblies, and industrial driver interface products. The method that currently is used in the company to create a wiring pattern is neither sufficient enough nor automated. In order to design the wiring pattern, at first procedure is handled by the designer. Secondly, car seat heater 2D layout is imported and then, the dimensions of the elements are defined as constraints. Then VBA codes are opened and the program is run. The result will be a wiring pattern in different 2D layouts. To make the design process easier, we have modeled five different layouts; wiring pattern of one element, two elements, three elements, five elements (with two back sides) and one element trapezoidal 2D layout. The algorithm written in VBA (Visual basic for application) creates the pattern according to the dimensions of the elements which are used as inputs to define constrained parameters. The created macros are simple to use and easy to modify, independent from the programming knowledge. The user is only responsible with parameter input and running the program. The solution gives wiring pattern for a car seat heater.

Målet med examensarbetet var att skapa ett verktyg för insamling av erfarenhetsdata för produktutvecklingsprocessen. Den skall vara användbar för att bidra till ett systematiskt arbetssätt för produktionsanpassad konstruktion på Volvo Aero Corporation. Det skapade verktyget för insamlande av erfarenhetsdata skall bidra till att produktivitet och producerbarhet kan förbättras på kommande koncept och konstruktioner. En förstudie har genomförts på företaget under hösten 2010 vilket ligger till grund för det beskrivna problemet i examensarbetet. Arbetet avgränsades till att utveckla en struktur för hur metod och erfarenhet skall struktureras och en testversion av verktyget togs fram för utvärdering. Efter samråd med den handledande Verksamhetsutvecklingsgruppen, VU-gruppen, från avdelning 9931 Projekt-, Koncept- och Tillverkningsledning, beslutades att examensarbetet skulle avgränsas ytterligare till insamling av diametermått på komponenten Diffuser Case på Volvo Aero. Under arbetets gång har återkommande möten veckovis infunnit sig med den utvalda VU-gruppen där också chefen från avdelningen och handledaren från företaget medverkat. Utgångspunkten för verktygets skapande var nuvarande produktion och dess information som finns att tillhandahålla. Det Design for Manufacturing-verktyg som skapats i Microsoft Excel samlar information från flera olika system och källor på Volvo Aero och presenterar denna information på ett pedagogiskt vis. Verktygets struktur har genom samråd med utvald VU-grupp tagits fram och de 35 kolumner som finns att fylla på med information är indelade i tre olika grupper för att erhålla ett systematiskt och pedagogiskt upplägg: basfakta, duglighet och kostnad samt bearbetningstid. Genom denna indelning erhålls en stigande detaljeringsgrad från vänster till höger i verktyget som ett medel för användaren att skapa ett tydligt och strukturerat arbetsätt. Kunskap, information och data som insamlas representerar uppgifter om kravnummer företaget serieproducerar idag. Verktyget skall med tiden fyllas på med fler uppgifter från strategiskt utvalda komponenter vilka stämmer överens med den inriktning företaget valt att gå i utvecklingen av nya komponenter. / The purpose of the Bachelor’s Thesis was to create a tool for the gathering of experience data for the product development process. It should contribute to a systematic operation approach at Volvo Aero Corporation. It should also contribute to improve productivity and producibility on future concepts. The problem described in the Bachelor’s Thesis is based on a pre-study performed at the company during the autumn 2010. The general task was defined as develop a structure for re-use of manufacturing experience and to create a test version of the tool for evaluation. After consultation with the selected Business Development-group from department 9931 Project-, Concept- and Manufacturing-leaders, the task was limited to gathering information of diameter dimensions from the Diffuser Case component at Volvo Aero. The creation of the tool had its starting-point in current production and the information available there. The Design for Manufacturing-tool has been created in Microsoft Excel and it’s developed in a way making it possible to gather and present information from different systems and sources. The tool presents the information in a pedagogical way that makes it user-friendly. The structure of the tool has been developed in consultation with the Business Development-group and the 35 columns of information is classified in three different groups: basic facts, capability and cost, operation time. By this classification the information level of detail increases from left to right which enables a more structured and systematic way of working. The knowledge, experience and data gathered represent information about the requirements the company currently produces. Over time, the Design for Manufacturing-tool is to be filled with more information from strategically chosen components which coincide with the direction the company has chosen for the development of new components.