Objective: A novel anthropomorphic test device (ATD) representative of the 50th percentile male soldier is being developed to predict injuries to a vehicle occupant during an underbody blast (UBB). The main objective of this study was to develop and validate a finite element (FE) model of the ATD lower limb outfitted with a military combat boot and to insert the validated lower limb into a model of the full ATD and simulate vertical loading experiments.
Methods: A Belleville desert combat boot model was assigned contacts and material properties based on previous experiments. The boot model was fit to a previously developed model of the barefoot ATD. Validation was performed through 6 matched pair component tests conducted on the Vertically Accelerated Loads Transfer System (VALTS). The load transfer capabilities of the FE model were assessed along with the force-mitigating properties of the boot. The booted lower limb subassembly was then incorporated into a whole-body model of the ATD. Two whole-body VALTS experiments were simulated to evaluate lower limb performance in the whole body.
Results: The lower limb model accurately predicted axial loads measured at heel, tibia, and knee load cells during matched pair component tests. Forces in booted simulations were compared to unbooted simulations and an amount of mitigation similar to that of experiments was observed. In a whole-body loading environment, the model kinematics match those recorded in experiments. The shape and magnitude of experimental force–time curves were accurately predicted by the model. Correlation between the experiments and simulations was backed up by high objective rating scores for all experiments.
Conclusion: The booted lower limb model is accurate in its ability to articulate and transfer loads similar to the physical dummy in simulated underbody loading experiments. The performance of the model leads to the recommendation to use it appropriately as an alternative to costly ATD experiments. 相似文献
The purpose of this study was to develop a relationship to evaluate the grip force (forcerel) using the electromyogram (EMGrel) of the flexor digitorum superficialis (FDS) and of the extensor digitorum (ED) according to the flexion-extension wrist angle (θf.e) and to the pronation-supination forearm angle (θp-s).Fifteen participants had to exert 3 levels of grip forces in 4 positions of the wrist combined with 3 positions of the forearm.The relationship is:forcerel = 0.0045· θf-e· EMGrel(FDS) + 0.48· EMGrel(FDS)–0.0014 · θf-e · EMGrel(ED) –0.0016 · θp.s · EMGrel(ED) + 0.4· EMGrel(ED)This relationship can be used to estimate grip force for levels of strength lower than 50% of the maximal voluntary contraction. 相似文献
Radial-ray reduction malformations (RRRMs) may occur isolated or in association with other anomalies. The data of seven fetuses born with RRRMs were collected. Six fetuses had associated lethal abnormalities of the central nervous system, urogenital system, and/or heart, detected by ultrasound. In five cases, it was possible to establish the precise diagnosis, enabling an informed prognosis and subsequent genetic counselling. The diagnoses were: Edwards syndrome (n=3), VACTERL association (n=1), and Poland-Moebius-like complex (n= 1). In two cases, a complete diagnosis was not possible because of inadequate evaluation of these fetuses before and/or after birth. A proposal is given for the diagnostic approach for infants with RRRMs detected in the antenatal period by means of ultrasonography. 相似文献
The prenatal diagnosis of Robinow' s syndrome was accomplished in our case by measuring the length of the long bones and the ulna/humerus ratio. Although the prenatal sonographic appearance did not show the typical 8-week fetal face, pathological findings confirmed this particular feature. In view of the strongly suggestive family history, the authors consider the possible mechanisms of genetic inheritance. 相似文献
Background. Although petrol pumps are a very common and highly used simple technology, their design consideration for comfort and safety to prevent high-pressure load and musculoskeletal injuries to the body is a neglected area in many countries including Iran. Objectives. This study attempted to design a new pump nozzle, and to assess the differences in musculoskeletal load related to body posture when a price/volume display is mounted on the pump nozzle. Methods. For postural analysis, photographs recording the posture of 100 randomly selected customers while fueling at petrol pumps and the rapid upper limb assessment (RULA) technique were used. Results. The results of this study showed that RULA scores improved significantly after the newly designed pump nozzle was used. Conclusion. The newly designed pump nozzle is useful in reducing load related to body posture while fueling. 相似文献
Introduction. Shoulder disorders are one of the most prevalent musculoskeletal disorders among carpet weavers. The most important cause of these disorders is muscle fatigue. The aim of the present study is to investigate the effect of carpet weaving characteristics on upper trapezius (UTr) muscle fatigue during a task cycle. Method. In this cross-sectional study, 9 women and 3 men participated. During an 80-min cycle of carpet weaving, a times-series model was applied to assess electromyography amplitude and frequency changes. Result. According to the joint analysis of electromyogram spectrum and amplitude method, the participants experienced 0% force decrease, 0.9% recovery, 18% force increase and 72% fatigue in the left UTr. Furthermore, the rates of force decrease, recovery, force increase and fatigue in the right UTr were 18%, 18%, 18% and 45%, respectively. Fatigue in the right and the left UTr was reported to be the dominant state during one carpet weaving task cycle. Conclusion. Task cycle appears to have a significant impact on UTr fatigue in participants, and UTr fatigue can be considered a serious risk factor in shoulder musculoskeletal disorders. Hence, further studies should focus on better workstations and work–rest periods during various subtasks. 相似文献