This thesis comprehends a series of nonlinear numerical studies with the finite element software's LS-Dyna and Impetus AFEA. The main focus lies on a comparative crash analysis of an aluminium beam profile which the company Sapa technology has used during their crash analysis. The aluminium profile has the characteristic of having different thickness over span ratios within the profile. This characteristic provided the opportunity to conduct a performance investigation of shell and solid elements with finite element analysis. Numerical comparisons were made between shell and solid elements where measurable parameters such as internal energy, simulation times, buckling patterns and material failures were compared to physical tests conducted prior to this thesis by Sapa technology. The performance investigation of shell and solid elements was initiated by creating models of the aluminium profile for general visualization and to facilitate the meshing of surfaces. The meshing procedure was considered to be an important factor of the analysis. The mesh quality and element orientations were carefully monitored in order to achieve acceptable results when the models were compared to physical tests. Preliminary simulations were further conducted in order to obtain a clear understanding of software parameters when performing crash simulations in LS-Dyna and Impetus AFEA. The investigated parameters were element formulations and material models. A general parameter understanding facilitated in the selection of parameters for actual simulations, where material failure and damage models were used. In conclusion, LS-Dyna was observed to provide a bigger internal energy absorption during the crushing of the beam with longer simulation times for solid elements when compared to shell elements. Impetus AFEA did on the other hand provide results close to physical test data with acceptable simulation times when compared to physical tests. The result difference obtained from the FE-software's in relation to physical crash experiments were considered to be varied but did indicate that shell elements were efficient enough for the specific profile during simulations with LS-Dyna. Impetus AFEA proved that the same time to be numerically efficient for energy approximations with solid elements refined with the third polynomial.

<p>Den här rapporten handlar om det examensarbete som utförts mot Volvo 3P genom forskningsprojektet Viktor. Viktor är ett projekt som ska visa möjligheten med virtuell produktframtagning av gjutna komponenter. Volvo 3P är ett företag som utvecklar lastbilar. Uppgiften har varit att visa möjligheten att använda topologioptimering som ett verktyg i konstruktionsfasen. Detta har gjorts med hjälp av ett case som erhållits från Volvo 3P. Ett nytt koncept för en av deras lastbilsnav har tagits fram. Konceptet visar på högre styvhet och en lägre spänningsnivå än dagens originalnav. Konceptet hade förmodligen aldrig uppkommit om det inte hade varit för topologioptimeringen. Rapporten behandlar de steg som utförs vid en topologioptimering med programvaran Altair Hypermesh Optistruct. För att verifiera de resultat som erhållits från topologioptimeringen har koncepten analyserats i Abaqus. Rapporten tar även upp begränsningar och svårigheter som användaren kan komma att stöta på under arbetets gång.</p> / <p>This report documents the final project which has been performed in collaboration with Volvo 3P through the science project named Viktor. Viktor is a project which will show the opportunities with virtual product development of cast iron products. Volvo 3P is a company which among other things develops trucks. The task has been to show opportunities with topology optimization as a tool in the construction phase. This has been done with help from a case that has been received from Volvo 3P. A new concept for one of their hubs has been developed. The concept shows greater stiffness and a lower stresses compared to the original hub. The concept would probably not have been developed without using topology optimization. This report concerns the multiple steps which are used to perform optimization with the computer program Altair Hypermesh Optistruct. To verify the results which has been received from the topology optimization Abaqus has been used as a FE-tool. The report also contains the limits and difficulties which can occur during the process</p>

Loss of bone in the mandible as a result from for example resection of bone tumors or trauma, can in more complex cases be reconstructed using a reconstruction plate to provide stability between the remaining mandible stumps. Different studies on reconstruction plates present a fracture rate of 2.8-9.8 %. The rate of plate fracture and plate loosening increases the need to improve the design of the reconstruction plate. A useful tool to find new designs for structures is topology optimization. Topology optimization is a mathematical based method where it is possible to define an optimization problem for a specific load case. Based on the defined problem, the solver calculates the most appropriate design to reach the final goal. The aim of this work is to investigate, describe, and discuss how new designs for reconstruction plates used for bridging large mandibular defects can be achieved by using topology optimization as a tool.   Two software programs handling topology optimization from Altair Engineering were used: SimLab 14.0 and HyperMesh 14.0. Both of them uses the solver OptiStruct to solve the defined topology optimization problem. The topology optimization problem was defined to minimize the compliance of the structure with an upper limit of the allowed volume fraction used for the new design. Three different clenching tasks were examined: right unilateral clench, clenching in the intercuspal position, and incisal clench. All three load cases resulted in different designs, the designs were also affected by the initial amount of screws used, and by the defined value on the allowed thickness of the created parts in the new design. The results gave an initial understanding of topology optimization, and indicated the possibilities a design process with topology optimization has to achieve new designs for reconstruction plates used for large mandibular fractures.

Den här rapporten handlar om det examensarbete som utförts mot Volvo 3P genom forskningsprojektet Viktor. Viktor är ett projekt som ska visa möjligheten med virtuell produktframtagning av gjutna komponenter. Volvo 3P är ett företag som utvecklar lastbilar. Uppgiften har varit att visa möjligheten att använda topologioptimering som ett verktyg i konstruktionsfasen. Detta har gjorts med hjälp av ett case som erhållits från Volvo 3P. Ett nytt koncept för en av deras lastbilsnav har tagits fram. Konceptet visar på högre styvhet och en lägre spänningsnivå än dagens originalnav. Konceptet hade förmodligen aldrig uppkommit om det inte hade varit för topologioptimeringen. Rapporten behandlar de steg som utförs vid en topologioptimering med programvaran Altair Hypermesh Optistruct. För att verifiera de resultat som erhållits från topologioptimeringen har koncepten analyserats i Abaqus. Rapporten tar även upp begränsningar och svårigheter som användaren kan komma att stöta på under arbetets gång. / This report documents the final project which has been performed in collaboration with Volvo 3P through the science project named Viktor. Viktor is a project which will show the opportunities with virtual product development of cast iron products. Volvo 3P is a company which among other things develops trucks. The task has been to show opportunities with topology optimization as a tool in the construction phase. This has been done with help from a case that has been received from Volvo 3P. A new concept for one of their hubs has been developed. The concept shows greater stiffness and a lower stresses compared to the original hub. The concept would probably not have been developed without using topology optimization. This report concerns the multiple steps which are used to perform optimization with the computer program Altair Hypermesh Optistruct. To verify the results which has been received from the topology optimization Abaqus has been used as a FE-tool. The report also contains the limits and difficulties which can occur during the process

With both tougher competition and legislations, companies always strive to improve their products while cutting unnecessary costs. This master’s thesis investigates if the after-treatment systems department at the heavy-duty vehicle company Scania CV AB in Södertälje, Sweden can improve their development process by implementing automated FEM pre-processes for welded sheet metal components. The research is based upon theory from various fields within product development, knowledge-based engineering, FEM and design optimization, contributing to an understating of what effects this project could have on the development process as a whole. Large parts of the pre-processes used at the department today were identified as repetitive and suitable for automation. Using a simplified CAD model of an after-treatment system as a case study, a methodology for more efficient FEM pre-processes was developed. The methodology includes changes to the workflow between the design engineer and the CAE engineer as well as a software that automatically meshes welded sheet metal products. First of all, the design engineer inserts lines representing the weld positions in the CAD model and exports the model to the CAE engineer. Hereafter, the CAE engineer simply selects necessary settings for the mesh and launches the developed software that automatically meshes the sheet metal components as well as identifies and meshes the welds. The technique used to mesh the welds in HyperMesh fails for certain weld characteristics, resulting in a robustness of 54 % of the total weld length for the worst case in the case study. These characteristics are welds crossing other welds, welds adjacent to a sharp corner and welds containing a sharp corner. By excluding these problem areas when defining the lines in CATIA, the robustness increases substantially to between 72 % and 88 % of the total weld length in the case study, where the exclusion zones represent 3 % of the total weld length. Based on the case study, the developed methodology could potentially shorten the iterative development process between the design and CAE engineer with a total of 25 %, while the CAE engineer’s tasks in the development process can be cut with up to 60 %. This allows for more time being focused on value-adding tasks, resulting in higher quality products and an increased profit for the company.

This work presents a study and implementation of the simulation of residual stresses in castings. The objects of study are a cast iron truck Hub part (provided by the company Volvo 3P) and an optimized version of the Hub resulting from the application of a topology optimization process. The models are solved through an uncoupled thermo-mechanical solidification analysis, performed both in the FE commercial software Abaqus and the FD commercial software Magmasoft and the results are compared. First, a thermal analysis is carried out where the casting is cooled down from a super-heated temperature to room temperature. The thermal history obtained, is then used as an external force to calculate the residual stresses by means of a quasi-static mechanical analysis, using a J2-plasticity model. The simulation procedures are explained through a simplified model of the Hub and then applied to the geometries of interest. A results comparison between the original Hub and its optimized version is also presented. The theoretical base is given in this work as well as detailed implementation procedures. The results shows that the part subjected to the topology optimization process develop less residual stresses than its original version.

Ride and handling are important areas for safety and improved vehicle control during driving. To meet the demands on ride and handling a number of measures can be taken. This master thesis work has focused on the early design phase. At the early phases of design, the level of details is low and the design freedom is big. By introducing a tool to support the early vehicle body design, the potential of finding more efficient structures increases. In this study, topology optimization of a vehicle front structure has been performed using OptiStruct by Altair Engineering. The objective has been to find the optimal topology of beams and rods to achieve high stiffness of the front structure for improved ride and handling. Based on topology optimization a proposal for a beam layout in the front structure area has been identified. A vital part of the project has been to describe how to use topology optimization as a tool in the design process. During the project different approaches has been studied to come from a large design space to a low weight architecture based on a beam-like structure. The different approaches will be described and our experience and recommendations will be presented. Also the general result of a topology-optimized architecture for vehicle body stiffness will be presented.

<p>This work presents a study and implementation of the simulation of residual stresses in castings. The objects of study are a cast iron truck Hub part (provided by the company Volvo 3P) and an optimized version of the Hub resulting from the application of a topology optimization process. The models are solved through an uncoupled thermo-mechanical solidification analysis, performed both in the FE commercial software Abaqus and the FD commercial software Magmasoft and the results are compared. First, a thermal analysis is carried out where the casting is cooled down from a super-heated temperature to room temperature. The thermal history obtained, is then used as an external force to calculate the residual stresses by means of a quasi-static mechanical analysis, using a J2-plasticity model. The simulation procedures are explained through a simplified model of the Hub and then applied to the geometries of interest. A results comparison between the original Hub and its optimized version is also presented. The theoretical base is given in this work as well as detailed implementation procedures. The results shows that the part subjected to the topology optimization process develop less residual stresses than its original version.</p>

Topology optimization is a method providing new direction in designing of a technical objects. The aim of topology optimization is to find optimal distribution of material in design space. This diploma thesis is focused on optimization of aircraft wing rib num.6 of the airplane EV-55 using a software HW/Optistruct 7.0 implemented in a software package HyperWorks 7.0. The optimization of the rib was calculated under four different load cases. Resulting shapes of the rib were then tested by strenght calculations in software ANSYS 10.0. Finally, the obtained data of weights of optimized ribs were compared with the weight of the original rib.