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With the introduction of air bags, occupant safety in frontal car crashes has been improved for upper regions of the body, such as the head and thorax. These improvements, however, have not helped improve the safety for the lower extremities, increasing their percentage of injuries in car crashes. Though lower extremity injuries are usually not life threatening, they can have long lasting physical and psychosocial consequences. An LSDYNA finite element model of the knee-thigh-hip (KTH) of a 50th percentile adult male was developed for exploring the mechanics of injuries to the KTH during frontal crash crashes. The model includes a detailed geometry of the bones, the mass of the soft tissue, and a discrete element representation of the ligaments and muscles of the KTH. The bones were validated using physical tests obtained from the National Highway Traffic and Safety Administration's (NHTSA) test database. The geometry, the material properties and the failure mechanisms of bone materials were verified. A validation was also performed against a whole-body cadaver test to verify contributions of passive muscle and ligament forces. Failure mechanisms in the tests and simulations were compared to ensure that the model provides a useful tool for exploring fractures and dislocations in the KTH resulting from frontal vehicle crashes. The validated model was then used to investigate injury mechanisms during a frontal car crash at different occupant positions. The role of muscle forces on these fracture mechanisms was explored and simulations of frontal impacts were then reproduced with the KTH complex at different angles of thigh flexion, adduction and abduction. Results show that the failure mechanism of the lower limb can significantly depend on the occupant position prior to impact. Failure mechanisms in the simulations were compared to results found in literature to ensure the model provides a useful tool for predicting fractures in the lower limb resulting from out-of-position frontal vehicle crashes. The FE model replicate injury criteria developed for ligament failure and suggested lowering the actual used axial femur force threshold for KTH injures both in neutral and out-of-position KTH axial impacts.

When developing an electric vehicle, it is essential to evaluate the deformation in and around the battery box for different crash scenarios, and it is necessary to develop a more advanced model that would take into account all the stress modes. Thanks to the excellent properties of Advanced High Strength Steel (AHSS) combine with high strength for more safety and weight reduction for less exhaust emission, AHSS is more and more commonly used in automobile industry. The material employed in this project is DOCOL 900M and it is a martensitic steel with yield strength higher than 700MPa.  The focus of the current work is to describe the experimental setup for the GISSMO model used in LS-DYNA. A number of experimental methods and theories have been reviewed. Different geometries of the test specimens under different stress triaxialities have been discussed. The study also compares the accuracy and robustness of each of the testing methods and setups. The effect of anisotropy of materials on the mechanical properties was studied. Some summaries about how to reduce errors in the experiment under the conditions of low costing and high efficiency have been discussed. According to the stress-strain response of ductile materials, the parameters of plasticity model can be calibrated. The material can be implemented in finite element software to calibrate the parameters of damage and the prediction of material failure can be achieved. The experiment and simulation are always good to be used together in the research.

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The objective of the present study is to investigate various problems associate with breast cancer and lung cancer patients. In this study, we compare the effectiveness of breast cancer treatments using decision tree analysis and come to the conclusion that although certain treatment shows overall effectiveness over the others, physicians or doctors should discretionally give different treatment to breast cancer patients based on their characteristics. Reoccurrence time of breast caner patients who receive different treatments are compared in an overall sense, histology type is also taken into consideration. To further understand the relation between relapse time and other variables, statistical models are applied to identify the attribute variables and predict the relapse time. Of equal importance, the transition between different breast cancer stages are analyzed through Markov Chain which not only gives the transition probability between stages for specific treatment but also provide guidance on breast cancer treatment based on stating information. Sensitivity analysis is conducted on breast cancer doubling time which involves two commonly used assumptions: spherical tumor and exponential growth of tumor and the analysis reveals that variation from those assumptions could cause very different statistical behavior of breast cancer doubling time. In lung cancer study, we investigate the mortality time of lung cancer patients from several different perspectives: gender, cigarettes per day and duration of smoking. Statistical model is also used to predict the mortality time of lung cancer patients.

The objective of the present study is to address some important questions related to prostate cancer treatments and survivorship among White and African American men. It is commonly understood that the risk of developing prostate cancer is higher in African American men than the other races. However, using parametric analysis, this study demonstrates that this perception is a "myth" not a "reality". The study further identifies the existence of racial/ethnic disparities by comparing the average mean tumor size, the median of survival time, and the survival function between White and African American men. These results underline the necessity of understanding the role of racial background in working towards improved clinical targeting, and thereby, improving clinical outcomes. Furthermore, parametric survival analysis was performed to estimate the survivorship of white men undergoing different treatments at each stage of prostate cancer. Additionally, to better understand the risk factors (age, tumor size, the interaction between age and tumor size) associated with survival time, an accelerated failure time model was developed that could accurately predict the rates of survivorship of white men at each stage of prostate cancer in accordance with whatever treatment they had received. Finally, the results of parametric survival analysis and the accelerated failure time model are compared among white men undergoing similar treatment at each stage of the disease.

Heart failure (HF) affects an estimated 5.8 million Americans, accounting for near 250,000 deaths each year. With shortages in available donor hearts, mechanical circulatory support (MCS) has emerged as a life-saving treatment for advanced stage HF. With growth in MCS use, a clinical and developmental need has emerged for a standard characterization and evaluation platform that may be utilized for inter-device comparison and system training. The goal of this research was to harness SynCardia's total artificial heart (TAH) to meet this need. We first sought to characterize the TAH in modern physiological terms - i.e. hemodynamics and pressure-volume loops. We then developed a model of HF using the TAH and mock circulatory system operating in a reduced output mode. We demonstrated that MCS devices could be incorporated and evaluated within the HF model. Finally, we characterized the operational envelope of SynCardia's Freedom (portable), Driver operating against varying loading conditions. Our results describe the hemodynamic envelope of the TAH. Uniquely, the TAH was found not to operate with time-varying elastance, to be insensitive to variations in afterload up to at least 135 mmHg mean aortic pressure, and exhibit Starling-like behavior. After transitioning the setup to mimic heart failure conditions, left atrial pressure and left ventricular pressure were noted to be elevated, aortic flow was reduced, sensitivity to afterload was increased, and Starling-like behavior was blunted, consistent with human heart failure. The system was then configured to allow ready addition of ventricular assist devices, which upon placement in the flow circuit resulted in restoration of hemodynamics to normal. Lastly, we demonstrated that the Freedom Driver is capable of overcoming systolic pressures of 200 mmHg as an upper driving limit. Understanding the physiology and hemodynamics of MCS devices is vital for proper use, future device development, and operator training. Characterization of the TAH affords insight into the functional parameters that govern artificial heart behavior providing perspective on differences compared to the human heart. The use of the system as a heart failure model has the potential to serve as a valuable research and teaching tool to foster safe MCS device use.

This master thesis is part of a big project at Siemens Industrial Turbomachinery (SIT) in Finspång aimed to use the operation experience available at SIT to predict the state of the gas turbines in general and some mechanical components in particular. The objective of the thesis is to continue the development of a prediction model based on experience data for estimations of a components lifetime. In a previous master thesis by Alessandro Olivi statistical analysis of environmental attributes effect on the expected lifetime of components in a gas turbine was performed. Olivi’s thesis constitutes the starting point on which to keep building to create a reliable prediction model. In this thesis extensive validation tests have been performed in order to further quantify the reliability of the model. Investigations aimed towards finding ways to further develop and improve the prediction model are carried out. The relevant new findings are applied to the model and analysis concerning improvements in the prediction accuracy is carried out. It was revealed that the model is able to make accurate predictions for most of the validation points for each failure mode, but more research is needed to obtain a completely reliable prediction model.

Les lanceurs spatiaux sont des structures complexes associant une multitude de composants. L’assemblage de ces éléments doit répondre à un niveau de performance élevé. Le collage structural demeure un bon candidat en raison des nombreux avantages qu’il présente. Cependant, cette technologie montre des inconvénients. En raison des changements brusques de géométrie et de propriétés matériaux, des concentrations de contraintes apparaissent aux extrémités du joint de colle. Ce phénomène appelé effets de bords est néfaste pour la tenue mécanique de l’assemblage collé. La présence des effets de bords exclut l’utilisation de critères en contrainte utilisés classiquement. Le dimensionnement d’assemblages collés requiert des outils fiables prenant en compte ces effets de bords. Dans cette étude, un modèle de ruine incrémentale, associant une approche en contrainte et en énergie, est utilisé. L’utilisation de cet outil dans un cadre industriel, impose de répondre aux besoins d’un Bureau d’Études, notamment en termes de coût de calculs. Afin de le diminuer, une implémentation semi-analytique, est tout d’abord développée. Puis, une seconde méthode d’implémentation, basée sur la méthode des Eléments Finis, permet une prévision plus précise de la ruine d’un assemblage. La pertinence de ces deux approches a été vérifiée pour plusieurs configurations de joints collés. Des campagnes d’essais, destinées à confronter les résultats expérimentaux aux prévisions numériques, ont été réalisées. Dans le cadre de ce travail, un montage de collage et d’essai pour assemblages tubulaires a en particulier été développé. L’objectif du pré-dimensionnement est d’identifier une zone d’intérêt dans l’ensemble du domaine d’étude. Aussi, une étude paramétrique peut être requise afin de réaliser cette tâche. Afin de réduire le coût de calcul, une méthode d’interpolation spatiale appelée Krigeage a été mise en œuvre, et permet la construction efficace d’une surface de réponse. / Space Launchers are complex structures composed of a large number of elements. The assembling of these components must show a high level of reliability. The use of adhesive bonding technology is an interesting solution since it presentsseveral assets compared to “classical” joint techniques (such as riveting, bolting and welding), mainly because it can help to construct lighter and less energy consuming systems However„ the implementation of adhesives also has somedrawbacks. Due to the strong variations of geometrical and material properties, stress concentrations appear at the extremities of the joint. This phenomenon; called edge effects; has a great influence on the failure of the bond. As a result, the simple use of a classical stress or energetic criteria is not appropriate to predict the fracture of such structures. Therefore, it is obvious that the design of bonded assemblies requires reliable tools to take the edge effects into account. In this work an incremental failure model, which combines the stress and energetic criteria, is used. In order to decrease the computational cost, a semi-analytical application of this model is proposed. This is intended to make the approach more interesting to be implemented in an industrial environment. The accuracy of the prediction of the failure load is enhanced by means of the Finite Element method. The reliability of both the semi-analytical and Finite Element approaches is verified by comparing the model predictions with experimental data issued from double-notched Arcan and tubular specimen geometries. The aim of the pre-design phase is to identify the critical area in the whole range of the application of the studied geometry. Therefore, the realization of a parametric study is required in order to build a response surface. In the present study, this has been achieved by means of spatial interpolation using the Kriging model.

In the automobile industry, there is a big push for the automotive car manufacturers to base engineering decisions on the results of Computer Aided Engineering (CAE) solutions, and to transform the prototyping and testing, from a costly iterative process to a final verification and validation step. The variability in components material properties and environmental conditions together with the lack of knowledge about the underlying physics of complex systems often make it impractical to make reliable predictions based on only deterministic CAE models. One such area is the CAE modelling of cast aluminium components. These cast aluminium components have gained a huge relevance in the automobile industries due to their commendable mechanical properties. The advantage of the cast aluminium alloys are being a well-established alloy system in manufacturing processes, their functional integrity and relatively low weight. However, the presence of pores and micro-voids obtained during the manufacturing process constitutes a specific material behaviour and establishes a challenge in modelling of the cast materials. Furthermore, the low ductility of the materialdemands for the advanced numerical model to predict the failure. The main focus of this master thesis work is to investigate modelling technique of a cast aluminium alloy component, a spring tower, for a drop tower test and validate the predicted behaviour with the physical test results. Volvo Car Corporation currently uses a material model provided by MATFEM for cast aluminium parts which are explored in this thesis work, to validate the material model for component level testing. The methodology used to achieve this objective was to develop a boundary condition to perform component level tests in the drop tower and to correlate these with the obtained results found by using various modelling techniques in the explicit solver LS-DYNA. Therefore, precise and realistic modelling of the drop tower is crucial because the simulation results can be influenced by major design changes. A detailed finite element model for the spring tower has been developed from the observations made during the physical testing. The refined model showed good agreement with the existing model for the spring tower and observations from physical tests.