| 1. |
- Cameron, Christopher John, 1980-
(författare)
-
Design of Multifunctional Body Panels in Automotive Applications : Reducing the Ecological and Economical footprint of the vehicle industry
- 2009
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Over the past century, the automobile has become an integral part of modern industrializedsociety. Consumer demands, regulatory legislation, and the corporate need togenerate a profit, have been the most influential factors in driving forward the evolutionof the automobile. As the comfort, safety, and reliability of the automobile haveincreased, so has its complexity, and most definitely its mass.The work within this thesis addresses the twofold problem of economy and ecologywith respect to sustainable development of automobiles. Specifically, the conflictingproblems of reducing weight, and maintaining or improving noise, vibration, andharshness behaviour are addressed. Potential solutions to these problems must also beexecutable at the same, or preferably lower production costs. The hypothesis is that byreplacing acoustic treatments, aesthetic details, and complex systems of structural componentsboth on the interior and exterior of the vehicle with a single multi-functionalbody panel, functionality can be retained at a reduced mass (i.e. reduced consumptionof raw materials) and reduced fiscal cost.A case study is performed focusing on the roof structure of a production vehicle. Fullvehicle and component level acoustic testing is performed to acquire acoustic functionalrequirements. Vibro-mechanical testing at the component level is performedto acquire structural functional requirements complimentary to those in the vehiclesdesign specifications. Finite element modelling and analysis is employed to createa model representative of the as-tested component and evaluate its acoustic and mechanicalbehaviour numerically. Results of numerical simulations are compared withthe measured results for both acoustic and mechanical response in order to verify themodel and firmly establish a set of acoustic and mechanical constraints for future work.A new, multi-layered, multi-functional sandwich panel concept is proposed which replacesthe outer sheet metal, damping treatments, transverse beams, and interior trimof the existing structure. The new panel is weight optimized to a set of structural constraintsand its acoustic properties are evaluated. Results show a significant reductionin mass compared to the existing system with no degradation of the acoustic environment.A discussion of the results is presented, as is a suggestion for future research.
|
|
| 2. |
- Aftab, Ahmad, 1979-
(författare)
-
Model-based design of haptic devices
- 2012
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Efficient engineering design and development of high precision and reliable surgical simulators, like haptic devices for surgical training benefits from model-based and simulation driven design. The complexity of the design space, multi-domains, multicriteria requirements and multi-physics character of the behavior of such a product ask for a model based systematic approach for creating and validating compact and computationally efficient simulation models to be used for the design process.The research presented in this thesis describes a model-based design approach towards the design of haptic devices for simulation of surgical procedures, in case of hard tissues such as bone or teeth milling. The proposed approach is applied to a new haptic device based on TAU configuration.The main contributions of this thesis are: Development and verification of kinematic and dynamic models of the TAU haptic device. Multi-objective optimization (MOO) approach for optimum design of the TAU haptic device by optimizing kinematic performance indices, like workspace volume, kinematic isotropy and torque requirement of actuators. A methodology for creating an analytical and compact model of the quasi-static stiffness of haptic devices, which considers the stiffness of; actuation system;flexible links and passive joints.
|
|
| 3. |
- Braz, T. B. C., et al.
(författare)
-
Thick ply versus thin ply composite laminate stiffened panel buckling and post-buckling behavior
- 2017
-
Ingår i: ICCM International Conferences on Composite Materials. - : International Committee on Composite Materials.
-
Konferensbidrag (refereegranskat)abstract
- For their weight reduction, thin web panels are often used in airspace industry. In this study, a basic fuselage section is represented by a stiffened panel composed by skin, frame, stiffeners and attachments, as conceived by Arakaki and Faria [1]. In this panel design, the structure withholds large loads after the buckling of the web. This study presents a comparison between thick and thin ply composite laminates behavior under shear buckling loads. The two concepts were modeled using the commercial finite element software Abaqus®. Buckling and post-buckling nonlinear behavior for both thick ply and thin ply laminates was analyzed and results were compared.
|
|
| 4. |
- Cameron, Christopher, et al.
(författare)
-
Balancing structural and acoustic performance of sandwich panels for vehicle applications with topology, property, and size optimization
- 2010
-
Ingår i: 7th Asian-Australasian Conference on Composite Materials 2010, ACCM 2010. - : ACCM-7 Organizing Committee. - 9781632660756 ; , s. 835-838
-
Konferensbidrag (refereegranskat)abstract
- Within this paper, a process for the design of a multifunctional sandwich body panel for vehicle applications is proposed. The method, presented with a case study, attempts to achieve a balance between structural and acoustic performance using numerical tools for topology optimization and combined size and property optimization. The goal of the work is to achieve an optimal distribution of traditional sandwich foam material and light weight acoustic foam within the core of the panel. The significance of the coupling between the panels inner face sheet and the acoustic foam is examined and proves to be a critical parameter in the design. An adaptation to existing topology optimization schemes is proposed to deal with the presence or absence of such a coupling. The results show promise in simplifying construction, reducing weight, and streamlining the assembly process.
|
|
| 5. |
- Cameron, Christopher, et al.
(författare)
-
Bearing strength performance of mixed thin/thick-ply, quasi-isotropic composite laminates
- 2021
-
Ingår i: Composite structures. - : Elsevier Ltd. - 0263-8223 .- 1879-1085. ; 261
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of using thin plies to increase the bearing strength of composite laminates has been investigated. A series of 5 laminates of theoretically identical stiffness with varying proportions of thin plies were manufactured using a single material system. Four specimens from each plate were tested for bearing strength and damage was subsequently characterized using an optical microscope. The results show that performance in terms of bearing stiffness, strength at onset of damage, and ultimate bearing stress increase proportionally with the increasing amount of thin plies within the stack. Shifting from a 100% conventional ply laminate to a 100% thin-ply laminate gave an increase of 47% in the strength at onset of damage. Placement of the thin plies within the stack was also shown to be important for strength at initial onset of damage. Microscopic examination of the failure modes for all samples showed fiber kinking, localized to the center of the hole, to be the dominant failure mode regardless of the stacking sequence. © 2020 The Authors
|
|
| 6. |
|
|
| 7. |
- Cameron, Christopher John, 1980-
(författare)
-
Design of Multifunctional Body Panels for Conflicting Structural and Acoustic Requirements in Automotive Applications
- 2011
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Over the past century, the automobile has become an integral part of society, with vastincreases in safety, refinement, and complexity, but most unfortunately in mass. Thetrend of increasing mass cannot be maintained in the face of increasingly stringentregulations on fuel consumption and emissions.The body of work within this thesis exists to help the vehicle industry to take a stepforward in producing vehicles for the future in a sustainable manner in terms of botheconomic and ecological costs. In particular, the fundamentally conflicting requirementsof low weight and high stiffness in a structure which should have good acousticperformance is addressed.An iterative five step design method based on the concepts of multifunctionality andmultidisciplinary engineering is proposed to address the problem, and explained witha case study.In the first step of the process, the necessary functional requirements of the systemare evaluated. Focus is placed on the overall system behavior and diverted from subproblems.For the case study presented, the functional requirements included: structuralstiffness for various loading scenarios, mass efficiency, acoustic absorption, vibrationaldamping, protecting from the elements, durability of the external surfaces,and elements of styling.In the second step of the process, the performance requirements of the system wereestablished. This involved a thorough literature survey to establish the state of theart, a rigorous testing program, and an assessment of numerical models and tools toevaluate the performance metrics.In the third step of the process, a concept to fulfil requirements is proposed. Here, amulti-layered, multi-functional panel using composite materials, and polymer foamswith varying structural and acoustic properties was proposed.In the fourth step of the process, a method of refinement of the concept is proposed.Numerical tools and parameterized models were used to optimize the three dimensionaltopology of the panel,material properties, and dimensions of the layers in a stepwisemanner to simultaneously address the structural and acoustic performance.In the fifth and final step of the process, the final result and effectiveness of the methodused to achieve it is examined. Both the tools used and the final result in itself shouldbe examined. In the case study the process is repeated several times with increasingdegrees of complexity and success in achieving the overall design objectives.In addition to the design method, the concept of a multifunctional body panel is definedand developed and a considerable body of knowledge and understanding is presented.Variations in core topology, materials used, stacking sequence of layers, effects ofperforations, and air gaps within the structure are examined and their effects on performanceare explored and discussed. The concept shows promise in reducing vehicleweight while maintaining the structural and acoustic performance necessary in the contextof sustainable vehicle development.
|
|
| 8. |
- Cameron, Christopher John, et al.
(författare)
-
Material Property Steered Optimization of a Multifunctional Body Panel to Structural and Acoustic Constraints
- 2009
-
Ingår i: Proceedings of the 17th International Conference on Composite Materials.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A conventional automobile roof, including structural and interior trim components, is replaced with a multi-layer, multi-functional sandwich construction. A weight optimizationis performed to tailor the material properties of the composite face sheets and multiple foam layers to meet structural constraints and acoustic requirements.
|
|
| 9. |
- Cameron, Christopher John, 1980-, et al.
(författare)
-
Material Property Steered Structural and Acoustic Optimization of a Multifunctional Vehcile Body Panel
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Conventional vehicle passenger compartments often achieve functional requirements using a complex assembly of components. As each component is optimized for a single task, the assembly as a whole is often suboptimal in achieving the system performance requirements. In this paper, a novel iterative design approach based on using a multi-layered load bearing sandwich panel with integrated acoustic capabilitiesis developed focusing on material properties and their effecton the systems behavior. The proposed panel is meant to fulfilmultiple system functionalities simultaneously, thus simplifying the assembly and reducing mass. Open cell acoustic foams are used to achieve acoustic performance, and the effect of altering the stacking sequence as well as introducing an air gap within the acoustic treatment is studied in detail to determine effects on the acoustic and structural performance of the panel as a whole.
|
|
| 10. |
- Cameron, Christopher J., et al.
(författare)
-
On the balancing of structural and acoustic performance of a sandwich panel based on topology, property, and size optimization
- 2014
-
Ingår i: Journal of Sound and Vibration. - : Elsevier BV. - 0022-460X .- 1095-8568. ; 333:13, s. 2677-2698
-
Tidskriftsartikel (refereegranskat)abstract
- Balancing structural and acoustic performance of a multi-layered sandwich panel is a formidable undertaking. Frequently the gains achieved in terms of reduced weight, still meeting the structural design requirements, are lost by the changes necessary to regain acceptable acoustic performance. To alleviate this, a design method for a multifunctional load bearing vehicle body panel is proposed which attempts to achieve a balance between structural and acoustic performance. The approach is based on numerical modelling of the structural and acoustic behaviour in a combined topology, size, and property optimization in order to achieve a three dimensional optimal distribution of structural and acoustic foam materials within the bounding surfaces of a sandwich panel. In particular the effects of the coupling between one of the bounding surface face sheets and acoustic foam are examined for its impact on both the structural and acoustic overall performance of the panel. The results suggest a potential in introducing an air gap between the acoustic foam parts and one of the face sheets, provided that the structural design constraints are met without prejudicing the layout of the different foam types.
|
|
