Whiplash is a neck injury caused by the sudden differential movement between the head and torso. Whiplash injuries are most commonly reported as a consequence of rear impacts in car accidents. They are regarded as minor injuries, but can still lead to long-term disablement and discomfort in the neck. Whiplash injuries can be mitigated by better car seat designs. For this purpose, head restraint geometry must be improved first, and then the dynamic performance of the whole seat must be assessed at all crash seventies. A biofidelic human-body model is a key requirement in designing whiplash mitigating car seats. This thesis presents the development of a 50th percentile male multi-body human model and several energy absorbing car seat designs. The human-body model is specifically designed for rear impact and validated using the responses of seven volunteers from Japanese Automobile Research Institute (JARI) sled tests, which were performed at an impact speed of 8 kph with a rigid seat and without head restraint and seat belt. A generic multi-body car seat model is also developed to implement various seatback and recliner properties, anti-whiplash devices (A WDs) and head restraints. Using the same driving posture and the rigid seat in the JARI sled tests as the basic configuration, several anti-whiplash seats are designed to allow different types of motion for the seatback and seat-pan. The major findings of this research are: -The human-body model simulates the effects of muscle contraction and its overall response is superior in comparison to the currently used models and dummies. -A criterion called the S-shape index (SSI) is developed based on the intervertebral angles of the upper and lower cervical spine. -The car seat design concepts are able to control and use crash energy effectively with the aid of anti-whiplash devices for a wide range of crash seventies. -In order to reduce whiplash injury risk, this study advocates energy absorbing car seats which can also provide head restraint contact as early as possible.

The Bistable Aerial Platform (BAP) has been developed in order to further enlarge the repertoire of devices available at the microscale. This novel device functions as a switch in that its platform can lock in two positions, up or down. Herein, it will be examined and explained, but a true understanding of its workings requires a better understanding of its compliant constituent parts. The Helico-Kinematic Platform (HKP), which serves as an actuator for the BAP, is currently under investigation by another researcher and will be merely touched upon here. The focus, therefore, will rest on the analysis of the Quadrantal Bistable Mechanism (QBM), the principle component of the BAP. A preliminary pseudo-rigid-body model, an aid for the understanding of compliant mechanisms, will also be examined for the QBM. The models developed for these two devices, the HKP and QBM, can later be combined to form a full model of the Bistable Aerial Platform.

We have designed and examined a compliant knee mechanism that may offer solutions to problems that exist for infants and toddlers who are just learning to walk. Pediatric prosthetic knees on the market today are not well designed for infants and toddlers for various reasons. Children at this age need a prosthetic that is light in weight, durable, and stable during stance. Of the eleven knees on the market for children, all but three are polycentric or four-bar knees, meaning they have multiple points of movement. Polycentric knees are popular designs because they offer the added benefit of stable stance control and increased toe clearance, unfortunately this type of knee is often too heavy for young children to wear comfortably and is not well suited for harsh environments such as sand or water, common places children like to play. The remaining three knees do not offer a stance control feature and are equally vulnerable to harsh environments due to ball bearing hinges. Compliant mechanisms offer several design advantages that may make them suitable in pediatric prosthetic knees -- light weight, less susceptible to harsh environments, polycentric capable, low part count, etc. Unfortunately, they present new challenges that must be dealt with individually. For example compliant mechanisms are typically not well suited in applications that need adjustability. This problem was solved by mixing compliant mechanism design with traditional mechanism design methods. This paper presents a preliminary design concept for a compliant pediatric prosthetic knee. The carbon fiber composite spring steel design was first built and then evaluated using Finite Element Analysis. The prototype's instant center was plotted using the graphical method. From our analysis position, force and stress information was gathered for a deflection up to 120 degrees. The instant centers that were plotted indicate that the knee has good potential in offering adequate stability during stance.

This thesis focuses on reconstruction of 3D environment model from a set of photographs followed by camera localization. It describes basic principles and techniques used to create environmental models and techniques for camera pose estimation from 2D camera points to 3D model points. It also examines the influence of parameters on the quality of reconstruction and the possibilities of localization. It compares the quality of the descriptors in the process of creation of the model and based on localization it allows to implement augmented reality.

Finite element human body models have in recent years become widely used in the area of vehicle safety evaluations. They make it possible to predict injury risk in specific areas, down to the organ level in the human body. An existing human body model, SAFER HBM includes a rib cage representing an average male. However, humans have a large variability in rib geometry and material properties leading to uncertainties in non-linear phenomena such as rib fracture risk. Hence, it cannot be known if predictions based on an average male representation are applicable to other similar individuals. In simulation studies with the SAFER HBM, rib cortical bone thickness, rib cross-sectional width, and rib cortical bone material properties have been identified as the most influential for the magnitude of rib strains and thus, they have a large influence on the strain-based rib fracture risk. This means that the predicted injury outcome is sensitive to the particular rib properties of an individual, and in a real-world scenario, a distribution of injury outcomes is expected across a population. Knowledge of the injury risk distribution can aid vehicle designers in developing safer vehicles. This distribution can be found through repeated human body model simulations with various rib properties, but due to the lengthy simulation times, this is not feasible. This thesis aims to predict human body model rib strain histories, given variations in the three biomechanical parameters, rib cortical bone thickness, rib cross-section width and rib cortical bone material with the help of graph neural networks (GNNs) for both single and mixed impact scenarios. Several variations of GNNs were used and implemented with help of PyTorch and PyTorch Geometric. An extensive hyperparameter study was performed on a small part of one human body model rib, to find the optimal combinations of hyperparameters and GNNs. The data used in training and evaluation of the networks was generated in LS-DYNA with SAFER HBM v10 and post-processed in Meta post processor. To be able to generate many training examples, the HBM was subjected to a simplified impact scenario consisting of a pendulum impact to the chest. As final verification, the trained GNNs were applied to predict rib strains in a vehicle impact scenario. Evaluation of the GNNs' prediction accuracy on the whole rib cage for all impact scenarios was made by studying the root mean square error along with differences in predicted and actual peak strain, rib fracture risk, time the peak strain occurs and the euclidean distance between the locations within the rib of real and predicted peak strains. The results showed that it is possible to accurately predict strain histories. Further, a multilayer perceptron (MLP) model consistently achieved the lowest errors in all measurements for mixed impacts. However, the trained model produced slightly unexpected errors for test data extracted from vehicle simulations compared to simplified simulations. This is an indication that retraining the model on data from vehicle simulations may be necessary. In conclusion, this thesis has shown the possibility to predict strain histories from a SAFER HBM rib cage extracted from simplified simulations and simulations including the full vehicle model, the SAFER HBM and all safety systems, to investigate the effects of human variability in the rib cage.

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A finite element human body model (FE HBM) is a detailed virtual model of the human body that, for example, is used for simulating traffic accidents. A problem with HBMs is that there is no simple way to position the HBMs in non-standard positions. As different postures during an impact will affect the body in different ways it is vital to have the ability to position the HBMs. In this project it was investigated if it is possible to position a HBM from THUMS, by first positioning only the skin and skeleton, as control points, in the 3D-graphics program Blender. Thereafter a radial basis function interpolation is utilised to morph the rest of the HBM into the new position. The results indicate that in theory, it is possible to position a HBM using a 3D-graphics software. However, the method developed in this project resulted in a disfigurement of the morphed model. The disfigurement is possibly due to the change in distance between the skin and skeleton when positioning those body parts in Blender. / En finit element människokroppsmodell (FE HBM) är en detaljerad virtuell modell av människokroppen som exempelvis används för att simulera trafikolyckor. Ett problem med HBM:er är att det inte finns något enkelt sätt att positionera dem i annat än standardpositioner. Eftersom olika kroppsställningar påverkar kroppen på olika sätt under en kollision är det viktigt att ha möjlighet att kunna positionera en HBM. I detta projekt undersöktes om det är möjligt att positionera en HBM från THUMS, genom att först positionera endast huden och skelettet, som kontrollpunkter, i 3D-grafikprogrammet Blender. Därefter användes en radiell basfunktionsinterpolation för att flytta resten av HBM till den nya positionen. Resultaten indikerar att det är möjligt att positionera en HBM med hjälp av ett 3D-grafikprogram. Metoden som utvecklades i detta projekt resulterade dock i en deformering av den positionerade modellen. Deformeringen beror möjligen på att avståndet mellan hud och skelett ändrades vid positioneringen av dessa kroppsdelar i Blender.

Existing classes of centrifugal clutch concepts were reviewed. The pseudo-rigid-body model (PRBM), rigid-body replacement synthesis, force-deflection analysis, compliance potential evaluation, and compliant concept evaluation were used to develop effective new centrifugal clutch concepts. These methods helped develop and model four novel compliant centrifugal clutch designs, model two existing designs, and identify a concept with excellent potential for low-cost centrifugal clutch applications. This concept, the floating opposing arm (FOA) clutch, doubles the torque capacity metric relative to existing compliant designs. Torque and engagement speed models for this clutch were developed and verified against four prototype clutches. Additional novel designs devel-oped through this work have lower torque capacities, but also show good potential because of other unique characteristics. All of the designs were prototyped and tested to measure their torque-speed relationships.

This work discusses the dynamic predictions of compliant mechanisms using the Pseudo-Rigid-Body model (PRBM). In order to improve the number of mechanisms that can be modeled, this research develops and identifies several key concepts in the behavior of beam segments where both ends are fixed to a rigid body (fixed-fixed flexible segments). A model is presented, and several examples are discussed. The dynamic behavior of several compliant segments is predicted using the PRBM and the results are compared to finite element analysis and experimental results. Details are presented as to the transient behavior of a typical uniform rectangular cross section beam. The results of this study are extended and applied to compliant planar mechanisms. It is shown by comparison with finite element analysis and experimental results that the PRBM is a good model of the physical system's dynamic behavior. The method is also demonstrated for use with compliant microelectromechanical (MEMS) systems.

This thesis work comprises the working and simulation procedures being involved in simulating motion capture data in AnyBody Modeling System. The motion capture data used in this thesis are ballet movements from dancers of Östgöta ballet and dance academy. The ballet movements taken into consideration are the arabesque on demi-pointe and pirouette. The arabesque on demi-pointe was performed by two dancers but the pirouette is performed by only one dancer. The method involved recording ballet movements by placing markers on the dancer's body and using this motion capture data as input to AnyBody Modeling System to create a musculoskeletal simulation. The musculoskeletal modeling involved creating a very own Qualisys marker protocol for the markers placed on the ballet dancers. Then implementing the marker protocol onto a human model in AnyBody Modeling System by making use of the AnyBody Managed Modeling Repository (TM) and obtain the kinematics from the motion capture. To best fit the human model to the dancer's anthropometry, scaling of the human model is done, environmental conditions such as the force plates are provided. An optimization algorithm is conducted for the marker positions to best fit the dancer's anthropometry by running parameter identification. From the kinematics of the motion capture data, we simulate the inverse dynamics in AnyBody Modeling System. The simulations explain a lot of parameters that describe the ballet dancers. Results such as the center of mass, the center of pressure, muscle activation, topple angle are presented and discussed. Moreover, we compare the models of the dancers and draw conclusions about body balance, effort level, and muscles activated during the ballet movements.