The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
John Hauser - One of the best experts on this subject based on the ideXlab platform.
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Optimal Control Based Dynamics Exploration of a Rigid Car With Longitudinal Load Transfer
IEEE Transactions on Control Systems Technology, 2014Co-Authors: Alessandro Rucco, Giuseppe Notarstefano, John HauserAbstract:In this brief, we provide optimal control-based strategies to explore the dynamic capabilities of a single-track car model that includes tire models and Longitudinal Load transfer. First, we propose numerical tools to analyze the equilibrium manifold of the vehicle. That is, we design a continuation and predictor-corrector numerical strategy to compute the cornering equilibria on the entire range of operation of the tires. Second, as a main contribution of this brief, we explore the system dynamics by the use of nonlinear optimal control techniques. Specifically, we propose a combined optimal control and continuation strategy to compute aggressive car trajectories. To show the effectiveness of the proposed strategy, we compute aggressive maneuvers of the vehicle inspired to testing maneuvers from virtual and real prototyping.
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optimal control based dynamics exploration of a rigid car with Longitudinal Load transfer
arXiv: Optimization and Control, 2011Co-Authors: Alessandro Rucco, Giuseppe Notarstefano, John HauserAbstract:In this paper we provide optimal control based strategies to explore the dynamic capabilities of a single-track car model which includes tire models and Longitudinal Load transfer. Using an explicit formulation of the holonomic constraints imposed on the unconstrained rigid car, we design a car model which includes Load transfer without adding suspension models. With this model in hand, we perform an analysis of the equilibrium manifold of the vehicle. That is, we design a continuation and predictor-corrector numerical strategy to compute cornering equilibria on the entire range of operation of the tires. Finally, as main contribution of the paper, we explore the system dynamics by use of nonlinear optimal control techniques. Specifically, we propose a combined optimal control and continuation strategy to compute aggressive car trajectories and study how the vehicle behaves depending on its parameters. To show the effectiveness of the proposed strategy, we compute aggressive maneuvers of the vehicle inspired to testing maneuvers from virtual and real prototyping.
Johannes Roths - One of the best experts on this subject based on the ideXlab platform.
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Regenerated Bragg Gratings in Panda Fibers for Simultaneous Temperature and Force Measurements at High Temperatures
Journal of Lightwave Technology, 2016Co-Authors: Leonhard Polz, Barbara Hopf, Andreas Jarsen, Michael Eitzenberger, Markus Lindner, Hartmut Bartelt, Johannes RothsAbstract:Simultaneous temperature and force measurements in an extended temperature range up to 500 °C were shown with a regenerated fiber Bragg grating in a polarisation maintaining fiber of type Panda. Type I gratings in Panda fibers were regenerated under application of a high temperature annealing process. During the first temperature cycle, a distinct hysteresis of the fiber's birefringence with temperature was observed, but reproducible dependencies of the birefringence on temperature were shown for subsequent temperature cycles. The birefringence of the fiber at room temperature was nearly doubled compared to the pristine fiber, and showed linear temperature dependencies below and above 500 °C, but with different sensitivities in both temperature ranges. A change in the temperature dependence of the birefringence can be explained by the crossing of the transition temperature of the stress applying parts (SAP) at around 500 °C. Below this temperature, measurements of temperature and applied axial forces showed reproducible and approximately linear responses of the sensor element, allowing a 2 × 2 matrix approach for simultaneous temperature and Longitudinal Load measurements to be applied in this temperature range. Above 500 °C, in contrast, the SAPs become viscous, resulting in a viscoelastic behaviour of the fiber.
Alessandro Rucco - One of the best experts on this subject based on the ideXlab platform.
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Optimal Control Based Dynamics Exploration of a Rigid Car With Longitudinal Load Transfer
IEEE Transactions on Control Systems Technology, 2014Co-Authors: Alessandro Rucco, Giuseppe Notarstefano, John HauserAbstract:In this brief, we provide optimal control-based strategies to explore the dynamic capabilities of a single-track car model that includes tire models and Longitudinal Load transfer. First, we propose numerical tools to analyze the equilibrium manifold of the vehicle. That is, we design a continuation and predictor-corrector numerical strategy to compute the cornering equilibria on the entire range of operation of the tires. Second, as a main contribution of this brief, we explore the system dynamics by the use of nonlinear optimal control techniques. Specifically, we propose a combined optimal control and continuation strategy to compute aggressive car trajectories. To show the effectiveness of the proposed strategy, we compute aggressive maneuvers of the vehicle inspired to testing maneuvers from virtual and real prototyping.
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optimal control based dynamics exploration of a rigid car with Longitudinal Load transfer
arXiv: Optimization and Control, 2011Co-Authors: Alessandro Rucco, Giuseppe Notarstefano, John HauserAbstract:In this paper we provide optimal control based strategies to explore the dynamic capabilities of a single-track car model which includes tire models and Longitudinal Load transfer. Using an explicit formulation of the holonomic constraints imposed on the unconstrained rigid car, we design a car model which includes Load transfer without adding suspension models. With this model in hand, we perform an analysis of the equilibrium manifold of the vehicle. That is, we design a continuation and predictor-corrector numerical strategy to compute cornering equilibria on the entire range of operation of the tires. Finally, as main contribution of the paper, we explore the system dynamics by use of nonlinear optimal control techniques. Specifically, we propose a combined optimal control and continuation strategy to compute aggressive car trajectories and study how the vehicle behaves depending on its parameters. To show the effectiveness of the proposed strategy, we compute aggressive maneuvers of the vehicle inspired to testing maneuvers from virtual and real prototyping.
Junjie Zeng - One of the best experts on this subject based on the ideXlab platform.
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pet frp concrete high strength steel hybrid solid columns with strain hardening and ductile performance cyclic axial compressive behavior
Composites Part B-engineering, 2020Co-Authors: Yuyi Ye, Junfan Lv, Yi Ouyang, Junjie Zeng, Cheng JiangAbstract:Abstract This paper presents the results of an experimental program on the behavior of fiber-reinforced polymer (FRP)-concrete-high strength steel solid columns (FCSSCs), with an outer polyethylene terephthalate (PET) FRP tube and an inner circular high-strength steel (HSS) tube, under cyclic axial compression. A PET FRP tube has a much larger rupture strain and a larger FRP hoop strain efficiency, leading to an excellent ductility of PET FRP-confined concrete. The HSS tube, which has a good deformation compatibility with the PET FRP-confined concrete in FCSSCs, provides a much larger Longitudinal Load carrying capacity and a larger confinement to the core concrete compared with a normal strength steel tube. The experimental results demonstrated that the axial Load carrying capacity of an FCSSC is much larger than the summation of the axial Load resistance of the hollow steel tube and that of the concrete-filled FRP tube; the buckling of the HSS tube is also prevented so that its post-yield material strength is effectively utilized. It is found that cyclic Load-strain envelope curves lie closely to the corresponding monotonic Load-strain curves, and repeated Loading cycles increase the plastic strain while decrease the reLoading new stress. The existing stress-strain model fails to provide an accurate prediction on the cyclic axial behavior of concrete under combined PET FRP-steel confinement.
T N Chakherlou - One of the best experts on this subject based on the ideXlab platform.
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an experimental investigation of the bolt clamping force and friction effect on the fatigue behavior of aluminum alloy 2024 t3 double shear lap joint
Materials & Design, 2011Co-Authors: T N Chakherlou, Mir Jalil Razavi, A.b. Aghdam, Babak AbazadehAbstract:Abstract In this article, the effect of bolt clamping force on the fatigue life of bolted double shear lap joints was investigated. To do so, fatigue tests were carried out on the bolt clamped double shear lap joint specimens made of aluminum alloy 2024-T3. These fatigue tests were conducted with applied torques of 0.25, 2 and 4 N m at different cyclic Longitudinal Load levels in un-lubricated and lubricated states. From these tests the stress–life (S–N) data for different clamping forces for un-lubricated and lubricated states were obtained. The results show that clamping force increases fatigue life compared to clearance fit specimens. In general, at higher tightening torque higher fatigue lives were achieved, however, below a certain Load level the life improvement was discontinued because of fretting phenomenon. Also lubricating the parts of the specimens reduces the advantage of clamping force or torque tightening.
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On the Variation of Clamping Force in Bolted Double Lap Joints Subjected to Longitudinal Loading: A Numerical and Experimental Investigation
Strain, 2011Co-Authors: T N Chakherlou, Mir Jalil Razavi, A.b. AghdamAbstract:: This study investigates the variation of clamping force and its concomitant effects on the performance of bolted double lap joints subjected to Longitudinal Loading. Two different amounts of clamping force were applied to bolted double lap joints made of Aluminium 2024-T3, and variations of clamping force were measured under the application of Longitudinal Loading. Finite element modelling was also performed to compare with experiments. The results unanimously revealed a gradual initial reduction of clamping force followed by a significant increase as the Longitudinal Load was increased. Also affected, was the Load transfer mechanism in the joint resulting in variation of friction force between the plates, but in a different trend compared to clamping force. Finally, the key parameters have been discussed and highlighted pertaining to the performance of the joint.
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reduction in clamping force due to applied Longitudinal Load to aerospace structural bolted plates
Aerospace Science and Technology, 2009Co-Authors: Reza Hashemi Oskouei, T N ChakherlouAbstract:The main purpose of the present work is to experimentally and numerically study why and how the magnitude of the bolt clamping force reduces in the aerospace structural bolted plates when they are subjected to a Longitudinal tensile Load. In the experimental method, a holed plate of aluminium alloy 7075-T6 was clamped using a single bolt fastener, and then tested under an increasing static Longitudinal tensile Load. The bolt clamping magnitude was determined by using the measured axial compressive strains of a steel bush placed between the nut and plate. Two clamped specimens with different initial clamping forces were studied. In each specimen the actual clamping forces were determined during the Longitudinal Loading on the plate. In the numerical method, a three-dimensional (3D) finite element model was generated in order to simulate and quantify the bolt clamping force in the plate model Loaded in tension. Both experimental and numerical results showed that the clamping force reduces considerably in the aluminium bolted plates under the Longitudinal tensile Loading. This is because of the transverse contraction of the plate material that causes the clamped material to release from the initial compression, and as a result, the clamping force to relax.
