This thesis deals with composite joints. Designing such joints is more difficult than metallic joints due to the mechanical properties of composite materials. Composites are anisotropic and have a limited ability of yielding. The low degree of yielding means that stress concentrations are not relieved by plastic deformation, which is important in multi-fastener single-lap joints. The distribution of load between the fasteners may be more uneven than in metallic joints due to that the stress concentrations around the holes are not relieved. Single-lap joints have an eccentric load path which generates a nonuniform bolt-hole contact pressure through the plate thickness. This generates out-of-plane deflection of the joint, termed secondary bending. Such nonuniform contact stress severely limits the strength of the joint. The nonuniform contact stress distribution is affected by several factors, e.g. bolthole clearance and secondary bending. The first part of the work is devoted to investigating secondary bending, and its effect on stresses in the joint. A novel technique to study secondary bending has been developed and used in a parametric study. It is based on the calculation of specimen curvature from out-of-plane deflections measured with an optical technique. It is shown that the specimen curvature is correlated to the conventional definition of secondary bending, which involves strain measurements on both sides of the plate. The two most important parameters affecting specimen curvature was found to be the overlap length and the thickness of the plates. The finite element method was used to study the influence of secondary bending on joint strength. Secondary bending was changed in magnitude by altering the length of the overlap region in a two-fastener specimen. It was found that secondary bending affects the local stress field around the fasteners and that it may change the strength and the mode of failure. The second part is concerned with the load distribution and prediction of joint strength. A detailed finite element model was developed to calculate the load distribution while accounting for bolt-hole clearances, bolt clamp-up, secondary bending and friction. An experimental programme was conducted in order to validate the finite element model by means of instrumented fasteners. Good agreement between simulations and experiments was achieved and it was found that bolt-hole clearance is the most important factor in terms of load distribution between the fasteners. Sensitivity to this parameter was found to be large, implying that temperature changes could affect the load distribution if member plates with different thermal expansion properties are used. Calculating the load distribution in structures with a large number of fasteners is in general not feasible with detailed finite element models based on continuum elements. A simplified, computationally effective model of a multi-fastener, singlelap joint has been developed by means of structural finite elements. The model accounts for bolt-hole clearances, bolt clamp-up, secondary bending and friction. Comparisons with the detailed finite element model and experiments validated the accuracy of the simplified model. A parametric study was conducted where it was found that an increased stiffness mismatch between the plates generates a more uneven load distribution, while reducing the length of the overlap region has the opposite effect. Increasing the stiffness of a fastener shifts some of the load from the nearest fasteners to that particular fastener. An idealized optimization study was conducted in order to minimize bearing stresses in the joint with restrictions on the increase of joint weight and net-section stresses. Maximum bearing stress was reduced from 220 MPa to 120 MPa while both weight and net-section stresses decreased. A procedure to predict bearing strength based on the results from the simplified model was developed. It was established by an experimental programme that fiber micro-buckling is the initial failure mode. The stress state in the laminate was determined through force and moment equilibrium, based on output from the finite element model. An existing criterion was used to predict the fiber microbuckling, and thus the initial failure. Predictions were compared with experiments which validated the method. The small computational cost required by the procedure suggests that the method is applicable on large scale structures and suitable to use in conjunction with iterative schemes such as optimization and statistical investigations. / QC 20110121

This thesis work was executed at Swift Engineering Incorporated located in San Clemente, California during spring in 2009. Placement supervisor from Swift was Mark Page and advisor and examiner from the Division of future products at Mälardalen University, Sweden was Gustaf Enebog. The objective with this thesis work was to examine the effects of fitness ratio, lift over drag, lift coefficient at cruise, winglet span, wing sweep angle, wing aspect ratio, wing area and weights with respect to Mach number for a conventional business jet capable of 18 passengers. The cruise speed study range from Mach 0.88 to 0.99. The Excel based conceptual design tool Jetsizer 2008c was used to make four models with similar configuration and mission but with different cruise Mach numbers. A new Jetsizer module was then created to handle a modification process where the models are optimized for their speed and configuration. The result in this report gives guidelines for the needed values when creating an initial CFD model for this type of airplane.

SAMMANFATTNING Detta arbete har gått ut på att i CAD implementera en UAV-design av Enebog, Designen har förmedlats av handledaren via möten och mail. Ett ”levande” dokument skapades och har sedan uppdaterats från båda sidor genom projektets fortlöpande. Dimensioner och mått har diskuterats samt hur det ska implementeras i CAD. UAV’n är uppbyggd som en ”assembly” i CAD, med tillhörande modeller och ”sub-assemblies”. Modellerna är designade i Solid Works standard-arbetsbänk och ihopsatta i assemblyn med så kallade ”mates”. Tyngdpunkt och massa har beräknats i Solid Works för flygplanets olika delar. Datat har exporterats till Excel för att kunna presenteras. Resultatet är 7 stycken 2D ritningar kopplade till en 3D modell. Flygplanet har en spännvidd på 2,7 meter och en vingarea på 0,91m2. Den totala längden dimensionerades till 1,87 meter och den totala massan kalkylerades till 8,68 kg, som också är flygplanets ”take off weight”. Flygplanet är designat för att byggas med två olika komposit material: kolfiber/epoxy och glasfiber/epoxy. I ritningsunderlaget genererares tre-plans vyer med måttsättning, detaljvyer på till exempel nos-poden i den främre delen av flygplanet samt en sprängskiss med innehållsförteckning. / ABSTRACT This work has been focused on implementing, into CAD (Solid Works), a UAV-design by Enebog. The design has been given to the author on meetings and mail. A “living” document with design parameters was updated from both sides continuously throughout the project. The measurements/dimensions of the aircraft were discussed as well as how to implement in CAD. All updates were also continuously updated in the document. The UAV is built up as an assembly in CAD, with sub-assemblies and parts. The parts are designed with the standard work bench in Solid Works and mated together to form an aircraft. Center of gravity and mass properties of the parts were calculated in Solid Works and exported to Excel for the purpose of presenting the data. The result is 7 2D drawings attached to a 3D model. The aircraft has a wing span of 2,7 meters (8,68 ft), with a corresponding wing area of 0,91 m2 (9,8 ft2). The total length is dimensioned to 1,87 m (6,14 ft) and the total mass is calculated to 8,68 kg (19,14 lbs), which is also the aircrafts takeoff weight. The aircraft is designed to be built with two composite materials; carbon fiber/epoxy and glass fiber/epoxy. In the drawing material plan views with dimensions of the aircraft, detail views of e.g. the nose pod in the front part of the aircraft, an exploded view with a corresponding build of material-table was generated.

<p>This thesis deals with composite joints. Designing such joints is more difficult than metallic joints due to the mechanical properties of composite materials. Composites are anisotropic and have a limited ability of yielding. The low degree of yielding means that stress concentrations are not relieved by plastic deformation, which is important in multi-fastener single-lap joints. The distribution of load between the fasteners may be more uneven than in metallic joints due to that the stress concentrations around the holes are not relieved. Single-lap joints have an eccentric load path which generates a nonuniform bolt-hole contact pressure through the plate thickness. This generates out-of-plane deflection of the joint, termed secondary bending.</p><p>Such nonuniform contact stress severely limits the strength of the joint. The nonuniform contact stress distribution is affected by several factors, e.g. bolthole clearance and secondary bending. The first part of the work is devoted to investigating secondary bending, and its effect on stresses in the joint. A novel technique to study secondary bending has been developed and used in a parametric study. It is based on the calculation of specimen curvature from out-of-plane deflections measured with an optical technique. It is shown that the specimen curvature is correlated to the conventional definition of secondary bending, which involves strain measurements on both sides of the plate. The two most important parameters affecting specimen curvature was found to be the overlap length and the thickness of the plates. The finite element method was used to study the influence of secondary bending on joint strength. Secondary bending was changed in magnitude by altering the length of the overlap region in a two-fastener specimen. It was found that secondary bending affects the local stress field around the fasteners and that it may change the strength and the mode of failure.</p><p>The second part is concerned with the load distribution and prediction of joint strength. A detailed finite element model was developed to calculate the load distribution while accounting for bolt-hole clearances, bolt clamp-up, secondary bending and friction. An experimental programme was conducted in order to validate the finite element model by means of instrumented fasteners. Good agreement between simulations and experiments was achieved and it was found that bolt-hole clearance is the most important factor in terms of load distribution between the fasteners. Sensitivity to this parameter was found to be large, implying that temperature changes could affect the load distribution if member plates with different thermal expansion properties are used.</p><p>Calculating the load distribution in structures with a large number of fasteners is in general not feasible with detailed finite element models based on continuum elements. A simplified, computationally effective model of a multi-fastener, singlelap joint has been developed by means of structural finite elements. The model accounts for bolt-hole clearances, bolt clamp-up, secondary bending and friction. Comparisons with the detailed finite element model and experiments validated the accuracy of the simplified model. A parametric study was conducted where it was found that an increased stiffness mismatch between the plates generates a more uneven load distribution, while reducing the length of the overlap region has the opposite effect. Increasing the stiffness of a fastener shifts some of the load from the nearest fasteners to that particular fastener. An idealized optimization study was conducted in order to minimize bearing stresses in the joint with restrictions on the increase of joint weight and net-section stresses. Maximum bearing stress was reduced from 220 MPa to 120 MPa while both weight and net-section stresses decreased.</p><p>A procedure to predict bearing strength based on the results from the simplified model was developed. It was established by an experimental programme that fiber micro-buckling is the initial failure mode. The stress state in the laminate was determined through force and moment equilibrium, based on output from the finite element model. An existing criterion was used to predict the fiber microbuckling, and thus the initial failure. Predictions were compared with experiments which validated the method. The small computational cost required by the procedure suggests that the method is applicable on large scale structures and suitable to use in conjunction with iterative schemes such as optimization and statistical investigations.</p>

<p>This thesis adopts a novel approach to propelling and controlling the dynamics of a vehicle by using autonomous corner modules (ACM). This configuration is characterised by vehicle controlled functions and distributed actuation and offers active and individual control of steering, camber, propulsion/braking and vertical load.</p><p>Algorithms which control vehicles with ACMs from a state-space trajectory description are reviewed and further developed. This principle involves force allocation, where forces to each tyre are distributed within their limitations. One force allocation procedure proposed and used is based on a constrained, linear, least-square optimisation, where cost functions are used to favour solutions directed to specific attributes.</p><p>The ACM configuration reduces tyre force constraints, due to lessen estrictions in wheel kinematics compared to conventional vehicles. Thus, the tyres can generate forces considerably differently, which in turn, enables a new motion pattern. This is used to control vehicle slip and vehicle yaw independently. The ACM shows one important potential; the extraordinary ability to ensure vehicle stability. This is feasible firstly due to closed-loop control of a large number of available actuators and secondly due to better use of adhesion potential. The ability to ensure vehicle stability was demonstrated by creating actuator faults.</p><p>This thesis also offers an insight in ACM actuators and their interaction, as a result of the force allocation procedure.</p>

Den här rapporten ämnar svara på frågan om och med hur mycket tröskelvärdena av alla inkommande komponenter, tillhörande ett MD-80 Engine change kit, kan höjas med och vilka kostnadsbesparingar en sådan höjning kan medföra. Undersökningen har föranletts av företaget SAS Components vilja att få reda på om en optimering av tröskelvärden kan leda till en minskning av kasserade komponenter hos dem. / This report’s aim is to verify if it is possible, and if so, by how much SAS Component could increase the threshold values of all incoming components belonging to an MD-80 Engine Change Kit. How would this raise in the components threshold lower SAS Component’s expenses?

Sammanfattning Dagens stigande bränslepriser gör det alltmer viktigt för tillverkare samt brukare av fordon, att fokusera på detaljer som kan minimera drivmedelåtgången. Scania linjetrafikbussar är utrustade med ett antal olika konfigurationer av kåpor som figurerar på bussarnas tak. Projektet har således innefattat att undersöka dessa ur ett aerodynamisk perspektiv i Mälardalens högskolas låghastighetsvindtunnel, förlagt vid Hässlö i Västerås. Resultaten som uppnåddes är att motståndskofficienten kan reduceras från CD=0,46 till CD=0,41 genom att omplacera orginalkåporna på andra positioner över taket. CD =0,39 erhålls genom att bruka de aerodynamiskt modifierade kåporna. Det skapar en vinst på 55-60 000 kr för orginalkåporna och motsvarande en vinst på 75-80 000 kr för de modifierade kåporna, räknat under bussens livslängd och en drivmedelkostnad på 8 kr/l. Beräkningarna är snålt tilltagna för att ej ge ett överskattat värde, utan är mer ett resultat i underkant. I bilagorna figurerar även andra värden som ger än mer större vinst i kronor Resultat uppnås då man tenderar minimera det återcirkulerande och energialstrande flöde som skapas inledningsvis på bussens tak under dess färd.

With the increased amount of on-board electric power driven by the ongoing hybridization, new ways to realize vehicles are likely to occur. This thesis outlines a future direction of vehicle motion control based on the assumptions that: 1) future vehicle development will face an increased amount of available actuators for vehicle propulsion and control that will open up for an increased variety of possible configurations, 2) the onboard computational power will continue to increase and allow higher demands on active safety and drivability that will require a tighter interaction between sensors and actuators, 3) the trend towards more individualized vehicles on common platforms with shorter time-to-market require design approaches that allow engineering knowledge to be transferred conveniently from one generation to the next. A methodology to facilitate the selection of vehicle configurations and the design of the corresponding vehicle motion controllers is presented. This includes a method to classify and map configurations and control strategies onto their possible influence on the vehicle's motion. Further, a structured way of implementing and managing vehicle and subsystem models that are easy to reconfigure and reuse is suggested and realised in the developed VehicleDynamics Library. In addition, generic ways to evaluate vehicle configurations, especially the use of the adhesion potential to identify safety margin and expected limit behaviour are presented. Special attention is given to how the characteristics of a vehicle configuration can be expressed so that it can be used in vehicle motion control design. A controller structure that enables a generic approach to this is introduced and within this structure, two methods for control allocation are proposed, via tyre forces and directly. The first method uses a developed mapping of available actuators as constraints onto the achievable tyre forces and inverse tyre models to calculate the actuator inputs. The second method allocates the actuator inputs directly for an adapted problem that is linearized around the current operating point. It is shown that the methods are applicable to a variety of different vehicle configurations without redesign. Therefore, the same controller can manage a variety of vehicle configurations and there is no need to recognize and treat each different situation separately. Finally, a road map on how to continue this research towards a possible industry implementation is given. Also suggestions on more detailed improvements for modelling and vehicle motion control are provided. / QC 20100629

Designing a Kids Train body and Chassis, where Body of a train plays an important role as it should be attractive, fun, educational, comfortable and safer for the kids. and the chassis should be able to withstand sufficient load and able to accommodate steering, battery, seating, motor, axles and bumper at all sides which is developed for SB international AB.A literature study is carried out to review various designs body of train and chassis, latest innovations and advanced materials used to manufacture the same. The various types of forces and stresses commonly acting on chassis structures are analyzed and their effects on the vehicle is understood and different types of train design is studied in order to make an attractive train for the kids by using Waterfall method to understand the concepts in designing a Train body. The pro-con analysis is conducted to evaluate merits and demerits of each alternative type of body of a train and the material to manufacture it. The most essential  design criteria are derived from the QFD (Quality function deployment) which then acts as important guidelines during the actual design process.Structural chassis frame is designed as per the design criteria with little modification and designing a body of a train using the CAD software CATIAV5R20 and the structural stability of the same is tested and analyzed using Inspire (solid thinking) software.

The automotive industry is in constant development and in recent years the environmental legislations have been getting tougher. The need for lighter and stronger materials has increased according to these changes and composite materials such as carbon fibre reinforced polymers is showing potential of being a solution due to their high specific properties. This thesis is an investigation and design proposal for one way of making a carbon fibre bus body wall structure by the use of pultruded beam elements and a certain number of standardised node elements. This is done to increase the possibility of mass production and possibly lower the manufacturing cost for a carbon fibre structure. The methodology is based on a product development process where a market research as well as a literary study was conducted initially to see what work had been done in the area. Needs were investigated and formulated to a product specification from which concepts was generated using brainstorming methods as well as discussions with bus design engineers at Scania. A number of materials and manufacturing methods was analysed for the node elements and after comparing and scoring different concepts, a carbon fibre node element was chosen. Dimensioning calculations were made based on standardised tests which simulates different driving scenarios. The concept was then designed in 3D-cad and the final weight of the concept was measured to 194 kg. A comparison of the concept with a steel bus was made by the use of the life cycle analysis tool in CES Edupack 2017 which resulted in a difference of 47 tonnes carbon dioxide released for a diesel driven light goods vehicle during the first six years of the lifetime. The overall results show that a carbon fibre bus body might be economically beneficial during the entire lifetime of a bus even though the purchase price is higher.