Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"Linear Stiffness"”.
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Effects of non-linear stiffness on performance of an energy harvesting device
… or hostile environments. To date, resonant linear generators have been the most common type of generators used in harvesting energy for such devices. Simple tuning and modelling methods make it a more favourable solution theoretically if not practically. This thesis considers the limitations …
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Adaptive gait strategies of healthy individuals walking with a novel bi-linear stiffness ankle-foot orthosis
… PD-AFO’s strut is the primary contributor to its stiffness properties, which can be customized and tuned to match an individual’s level of need. However, the vast majority of PD-AFOs are manufactured with a single, unchanging strut stiffness. Recent work examining the stiffness properties of the …
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Experimental Measurements of Vestibular Hair Bundle Stiffness in the Red Ear Slider Turtle Utricle
… perform different functions. In this study, the linear and torsional stiffnesses were measured for hair cells located in the red ear slider turtle utricle. The system used to measure the stiffnesses was composed of a glass whisker (attached to a pipette) used to produce a force on the tip of the …
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Inverse dynamic modeling for characterization of spasticity
… this research has shown that there is nonlinearity at the highest velocity of the pendulum knee drop test due to muscle activation. In spastic subjects, this research has also demonstrated that the passive linear stiffness is increased. This work now allows biomechanical variants to be …
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The Influence of Semi-Rigid Connections on the Behaviour of Beam and Column Structural System
… was mainly theoretical with the assumption of a linear stiffness. Twenty beam end connector tests were carried out to study the effect of loading and unloading on joint behaviour. In each test two methods of displacement measurements were used in obtaining the moment curvature relationship. The …
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Numerical Modelling of Ball Bearing Stiffness to Predict Contact Stress Caused by Vibration Induced Gapping
… gapping using for the calculation, the bearing stiffness predicted by a computer software called CABARET, with satisfactory results. In the present study the model optimized, as the comparison with available measured gapping values verifies, by the introduction of the non-linear stiffness to the …
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Compliant Mechanism Suspensions
… These new concepts demonstrate increased stiffness and decreased stress due to control forces. Of these concepts, the compliant A-Arm proves to be the most promising candidate for future development. It has added advantages of lower space requirements, lower number of extra joints and …
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Asymptotic post-buckling analysis by Koiter's method with a general purpose finite element code
… Koiter’s method in the finite element form, the linear and incremental stiffness matrices are required. These matrices comprise the tangent stiffness matrix. As EAL uses the modified Newton-Raphson procedure to solve nonlinear structures, it calculates the tangent stiffness. The first and second …
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Stiffness Model of a Die Spring
… research is to determine the three-dimensional stiffness matrix of a rectangular cross-section helical coil compression spring. The stiffnesses of the spring are derived using strain energy methods and Castigliano's second theorem. A theoretical model is developed and presented in order to …
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Combined Time and Frequency Domain Approaches to the Operational Identification of Vehicle Suspension Systems
… the basis for the development of an accurate nonlinear simulation of the quarter car test rig. A comprehensive understanding of the quarter car experimental test rig dynamics is obtained before operational identification is implemented. This provides a means of validating the suspension …
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Development and validation of a computational multibody model of the elbow joint
… muscle loading, and multiple bundles of non-linear ligaments wrapped around the bones. In this approach, three-dimensional bone geometries for the model were constructed from volume images generated by computed tomography (CT) scans obtained from cadaver elbows. The ligaments and triceps …
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Modeling of equilibrium point trajectory control in human arm movements
… the use of complex virtual trajectories, non-linear damping, stiffness and time varying stiffness to the EPH model. While these features allow the EPH to adequately produce human joint velocities, they conflict with the EPH's premise of simple pre-planned monotonic control of movement …
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Study of driver-seat interactions and enhancement of vehicular ride vibration environment
… area. The results are utilized to propose a nonlinear and asymmetric seat cushion model. A nonlinear suspension seat model is further developed to incorporate asymmetric force-velocity and nonlinear force-deflection characteristics of the damper and elastic end-stops, respectively. A combined …
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Preliminary Investigation of the Mechanical Properties of Costal Cartilage and Costochondral Junction in Three-Point Bending
… which did not fail during the test. Only linear stiffness was calculated for these samples. The failure location along the testing span length was also calculated for the samples that failed successfully. The effects of sample type, age, and sex on the structural properties were …
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Airflow sensing with arrays of hydrogel supported artificial hair cells
… content to stimulus location by "tuning" linear, three-unit arrays of AHCs. Individual AHC sensors characterization results demonstrate peak current outputs in the nanoamp range and measure flow velocities as high as 72 m/s. Characterization of the AHC response to base excitation and air …
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Intentional nonlinearity in the small scale with applications to atomic force microscopy (AFM) and mass sensing
… systems were studied within the framework of linear dynamics, and incidental nonlinearity was suppressed by design. More recently, researchers have intentionally incorporated nonlinearity in the design of such devices in order to exploit the rich nonlinear behavior. Some of the nonlinear …
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Magneto-mechanical systems for ultra-low frequency data transmission: Dynamics, losses, and driving mechanisms
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2026-12-01