Investigation of the Dynamic Interaction between the Human Body and Car Seat Using a Unique Simulation Technique

Numerical simulations and mathematical models have been developed over last many years on the certain portions of human body, car seat or automobile to characterise, monitor and assess the level of vibration and its effects on the human occupant inside the automotive. Though, the numerical simulations can define the level and nature of vibration and its transmissibility up to a certain stage, vibration measurement techniques have also been gaining importance for last several years to fill the limitations of the theoretical models. Efforts have also been made to carry out vibration related investigations using combined numerical simulation and measurement procedure for the car seat and the seated human body inside car, though the numbers of case studies carried out with the combination of simulation and measurement procedure are very less. Some technologies have been achieved to judge the level of vibration inside the car seat and its human occupant, though those technologies cover only effects of vibration, dynamics or measurement techniques on specific portions of the car or the human body without considering all the real life factors, e.g., human gender, shape of the human portions, size specific stiffness properties, in-vehicle operating conditions and damping factors. Approaches to provide a comprehensive solution to estimate the level of vibration without real life testing have not been carried out by the existing technologies very well. More than that the existing technologies investigate only particular modules of the entire human-car dynamic systems, e.g., a specific human part, seat and human interaction, vibration transmission from seat to human body or the vibration measurement technique. So, there is enormous scope of further improvement and the aim of this research work is to provide a unique simulated system considering all the critical real life factors. Outcome of this simulation study will evaluate the vibration levels inside the segments of seated human body inside a car and car seat omitting the necessity of real-life practical testing and provide the solution by linking module-wise investigations of human body and car seat. Initiative has been taken to fill up the gaps in the existing technologies and offer a novel study on the comprehensive simulation model of the combined human body and car seat bio-dynamic system to optimize the health, safety and comfort levels of the car seated human body. Present research work covered the tasks of establishing the simulations for non-linear bio-dynamic model of the seated human body, feasibility and behaviour inspection of polyurethane foam cushions, contact mechanism assignment between the human body and the car seat and establishing the simulation of car seated human occupant under the real life environment. Vertical displacements, vertical accelerations and frequencies at designated points of human body and car seat have been extracted from the simulation outcome and the obtained results have been validated though real-life vibration testing data. This unique simulation methodology can successfully be implemented to predict the final vibration levels inside the car seat and the car seated human body to optimize the health, safety and comfort of the human-car seat system. The outlined novel technique contributed knowledge to the entire human body and car seat dynamic system rather than focusing only on a very specific portion of the system. An industrial guideline has been presented to implement this unique simulation methodology in similar sectors, which will lead various industries to avoid time consuming and expensive bio-dynamic vibration testing methods and help to understand the impact of vibration on the in-vehicle human body in a better way

Prototyping for Research and Industry

In this thesis we want to present some of the activities carried out during the PhD studies held at the PhD School "L. da Vinci" in the period from January 2012 to December 2014. The activities were held in the fields of robotics and mechanical engineering, and the main theme was the prototyping of new concepts, as well as the activity of conceptual design in its different phases, from generation of the idea, to the realization and testing of prototypes. The conceptual design phase is of fundamental importance to structure the process of generation of new ideas. Sometimes it is a process that is carried out unconsciously by the inventor. Providing a tool that allows to guide him in the various stages of idea generation can lead to advantages that let the inventor to explore areas from which take inspiration, which otherwise would not have been taken into account. An aspect of fundamental importance in the development of new prototypes is a process that goes in the opposite direction of the idea generation phase. Initially the conceptual design tends to provide tools to generate as many ideas as possible, but at some point there is the need to select a limited number of cases to investigate. Through the selection phase, which can be structured at levels more or less structured, and more or less qualitative/quantitative, the inventor tends to identify, case by case, which are the ideas in which is worth investing time and resources, before moving to the following stages. Prototyping, as well as its previous phase, now commonly called pretotyping, are mandatory steps for those who want to develop any new idea. The success of the final product or service may depend from the analysis of the pretotype first, and of the prototype later, since it allows to detect limits and possible improvements of the concept before moving to the final implementation phase

Advanced Testing and Characterization of Bituminous Materials, Two Volume Set

Bituminous materials are used to build durable roads that sustain diverse environmental conditions. However, due to their complexity and a global shortage of these materials, their design and technical development present several challenges. Advanced Testing and Characterisation of Bituminous Materials focuses on fundamental and performance testin

Advanced Testing and Characterization of Bituminous Materials, Two Volume Set

Bituminous materials are used to build durable roads that sustain diverse environmental conditions. However, due to their complexity and a global shortage of these materials, their design and technical development present several challenges. Advanced Testing and Characterisation of Bituminous Materials focuses on fundamental and performance testin

NASA Tech Briefs, October 1990

Topics: New Product Ideas; NASA TU Services; Electronic Components and Circuits; Electronic Systems; Physical' Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

Synthesis and characterization of mechanical properties of a novel bioceramic composite material for biological applications

Thesis (M.S.) University of Alaska Fairbanks, 2010Bioceramics are used in a wide range of human skeletal repair and restoration applications as a synthetic bone substitute. 45S5 Bioglass, a bioactive ceramic, exhibits poor mechanical properties limiting the potential of the material and preventing its use in major load bearing applications. This investigation evaluated the synthesis and mechanical properties of a 45S5 Bioglass composite reinforced with different weight percentages of multi-wall carbon nanotubes. The material was analyzed using an X-Ray Diffractometer and a scanning electron microscope to determine the crystal structure, microstructural homogeneity, and surface texture of the composite material. The material was evaluated during the synthesis process to observe the evolution of the composite. Samples were sintered at 1000°C and 850°C to determine the effect of the sintering temperature on the mechanical properties of the composite. Once synthesized, the material was tested using the Vickers hardness indentation test to determine the mechanical properties of the ceramic, as defined by hardness and fracture toughness values. Hardness of the composite decreased with increasing nanotube concentration for all samples. A maximum fracture toughness value of 47.6 GPa·m¹/² corresponded to the addition of 1 weight percent multi-wall carbon nanotubes in the composite samples sintered at 1000°C. All of the composite samples sintered at 850°C reported lower fracture toughness values than the pure bioglass samples indicating that sintering temperature affects bonding between the composite components. These results prove that a Bioglass-multi-wall carbon nanotube composite has the potential for use as a synthetic material to restore function in load bearing bone

From Benchtop to Beside: Patient-specific Outcomes Explained by Invitro Experiment

Study: Recent analyses show that females have higher early postoperative (PO) mortality and right ventricular failure (RVF) than males after left ventricular assist device (LVAD) implantation; and that this association is partially mediated by smaller LV size in females. Benchtop experiments allow us to investigate patient-specific (PS) characteristics in a reproducible way given the fact that the PS anatomy and physiology is mimicked accurately. With multiple heart models of varying LV size, we can directly study the individual effects of titrating the LVAD speed and the resulting bi-ventricular volumes, shedding light on the interplay between LV and RV as well as resulting inter-ventricular septum (IVS) positions, which may cause the different outcomes pertaining to sex. Methods: In vitro, we studied the impact of the heart size to IVS position using two smaller and two larger sized PS silicone heart phantoms derived from clinical CT images (Fig. 1A). With ultrasound crystals that were integrated on a placeholder inflow cannula, the IVS position was measured during LV and RV volume changes (dV) mimicking varying ventricular loading states (Fig. 1B). Figure 1 A Two small (blue) and two large PS heart phantoms (orange) on B benchtop. C Median septum curvature results. LVEDD/LVV/RVV: LV enddiastolic diameter/LV and RV volume. Results: Going from small to large dV, at zero curvature, the septum starts to shift towards the left; for smaller hearts at dV = -40 mL and for larger hearts at dV = -50 mL (Fig. 1C). This result indicates that smaller hearts are more prone to an IVS shift to the left than larger hearts. We conclude that smaller LV size may therefore mediate increased early PO LVAD mortality and RVF observed in females compared to males. Novel 3D silicone printing technology enables us to study accurate, PS heart models across a heterogeneous patient population. PS relationships can be studied simultaneously to clinical assessments and support the decision-making prior to LVAD implantation

Comparative Evaluation of Vertical Facial Height Reduction and Severity of Temporomandibular Joint Disorders Versus Controls using Shimbashi Number and Cephalometric Analysis

BACKGROUND: Bite collapse is a Medical and a dental dilemma where the patient’s bite and Temporomandibular joint (TMJ) do not function in harmony because of loss of vertical dimension of occlusion. It is an abnormal state in which mandible rises beyond the point of normal occlusal contact, caused by drifting of teeth, loss of occlusal vertical dimension, change in tooth shape and size through grinding, loss of teeth or abnormal positioning of lower jaw to the cranium. Bite collapse causes symptoms like frequent headaches, dull pain of the elevator muscles, ear stiffness, tinnitus and vertigo. Maintenance of ideal vertical dimension of occlusion is very important for optimal functioning of jaw muscles. Many studies were carried out in the past to diagnose bite collapse and to evaluate neuromucular and TMJ disorders associated with loss of vertical dimension of occlusion by analysing soft tissue and skeletal parameters. However, there are only very few studies that analysed the dental and skeletal parameters in the diagnosis of collapsed bite and explains the importance of re- establishing physiologic vertical dimension. The significance of this study was that it explains the amount of bite reduction and severity of Temporomandibular Joint disorders, which in turn would shed new light in the management of neuromuscular and Temporomandibular Joint disorders. Shimbashi number is the easiest Dental tool to analyse occlusal vertical dimension and Cephalometric evaluation of facial skeletal proportion in vertical direction is more accurate. AIM OF THE STUDY: The main aim of the study was to determine the extent of reduction in occlusal vertical dimension and it’s correlation to the severity of TMJ disorders by measuring ‘Shimbashi number and Cephalometric analysis. MATERIALS AND METHODS: Patients with a clinical history suggestive of TMJ disorders were taken and measured Shimbashi number with digital vernier caliper when the teeth were in maximum intercuspation or in centric occlusion. Shimbashi number is 19 mm plus or minus 1mm. Patients identified with collapsed bite and controls were subjected to a cephalometric analysis. Compared clinically obtained Shimbashi number with the measurement CEJ-CEJ in the radiograph. Correlated the other results obtained from cephalometric analysis with the Shimbashi number and evaluated changes in vertical dimension of occlusion in TMJ disorders. All the values were compared with the control group. RESULTS: The results of this study showed the prevalence of temporomandibular joint disorders increases with age and females are more prone to TMD. There was a significant reduction in values like Shimbashi number, Radiographic CEJ-CEJ, A-B, ANS-Gn, N-Gn, S-Go,< N-Go-Gn and < ANS-PNS-(Go -Gn) in patients with TMD. It also shows a significant increase in interincisal angle in TMD compared to controls. All parameters are significant and P value less than 0. 05. Result revealed the severity of TMD increases with reduction in values like Shimbashi number and Radiographic CEJ-CEJ and increase in interincisal angles. CONCLUSION: Temporomandibular joint disorder is one among the major reasons in which patients seek dental treatment and bite collapse is a major causative factor. This study revealed, how bite collapse or reduced vertical dimension of occlusion affects TMJ, and its correlation to the severity of joint disorders by clinically measuring Shimbashi number and Cephalometric analysis. Based on the result of this study, females are more prone to TMD and the prevalence of TMD increases with age. It also revealed that the severity of TMD increases with the degree of reduction in vertical dimension of occlusion

NASA SBIR abstracts of 1991 phase 1 projects

The objectives of 301 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1991 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 301, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1991 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included