Digitized by Kansas Correctional Industries

Particle distribution and settling in suspensions with non-Newtonian liquids agi- tated with a Rushton turbine in a lab-scale tank have been studied. The rheology of the non-Newtonian liquids can be described by the power-law, Bingham and Herschel-Bulkley fluid models. The dynamics of the dispersed phase settling particles (size 0.65mm) is modeled by a Lagrangian tracking approach while the liquid phase is resolved by the lattice-Boltzmann method. Qualitative insight emerging from exploration of shear-thinning/thickening, New- tonian, yield-stress fluid models at Reynolds number, Re=6 103 , 8.5 103 and 1.25 104 indicate that bottom particle concentration is highest in power-law liq- uids than in Newtonian; while yield stress fluids had more uniform particle con- centration and least bottom concentration. Also, turbulent kinetic energy and vis- cous dissipation are highest in the Newtonian liquid. Extra viscous diffusion due to fluctuating non-Newtonian viscosity in the turbulent kinetic energy equation attributes to these differences. / Chemical Engineering

The all-terrain vehicle (ATV) has been popular due to its simplicity in controlling, high recreational value, and sports utility, Furthermore, seating comfort and control aptness are affected mainly by the suspension and steering mechanism. Therefore, this research is directed towards the ATV¡¦s front suspension and steering mechanism, bearing in mind a set of systematized design procedures as the design and development basis of the front suspension and steering mechanism. First, we will investigate the papers on the front suspension and steering mechanism in order to make an induction on its characteristics and demand. Then, the theories of kinematic analysis of the front suspension and steering mechanism are established. The aided analyzing computer program we edit using the theories, moreover could be the design basis. And, to carry out the creative design of the front suspension and steering mechanism using the systematized procedure of creative mechanism design. In this investigation, we have successfully constructed atlas of the creative mechanism, and the result supplies the following design to select; Finally, we complete the kinematic design of the front suspension and steering mechanism based on the Genetic algorithm (GA), and we can obtain the better mechanism dimensions than Yamaha 660 ATV.

Extr. de: Diss.--Physique--Stuttgart (Allemagne)--Université de Stuttgart, 2001. / Thèse rédigée en anglais avec un résumé en allemand. Bibliogr. p. 183-188.

Thesis (D. SC.)--University of Michigan. / "Photo-lithoprint." Bibliography: p. 37.

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This thesis has been done at the company MarineDiesel Sweden, which is currently developing a diesel-powered outboard engine. The focus of the thesis is to design and size a trim/tilt-suspension unit, which secures the outboard to the boat. This system allows adjustments to be done to the outboard while driving in order to achieve better performance and a smoother ride.The methods used in this thesis are brainstorming/concept generation, concept selection, load analyses, CAD-modeling and FEM-analyses. One concept was chosen to proceed with, and further development was carried out. This involved design loops due to feedback from the company as well as the results from the FEM-analyses.The final result is a complete suspension unit, modeled and calculated strength wise, in order for it to fulfill the demands set on it. Four major parts were investigated using FEM, and analyzed in order to keep the stresses low as well as eliminating unnecessary material and thereby reducing weight. The material selected is aluminum, which is lightweight and possible to cast in order to produce complex geometries.

Wheelchair users are exposed to whole-body vibrations, particularly when traversing rugged terrain such as in less resourced areas. Suspension systems have been added to wheelchair systems to protect occupants from secondary injuries associated with whole-body vibration. Current suspension systems need to be further developed in order to optimize the protection against these secondary injuries. Until further research finds conclusive evidence for comfort level, and the onset of injury due to vibrations, it has been recommended to reduce whole-body vibration exposure to the lowest possible level. A versatile testing apparatus and method were designed and built to detect the acceleration and frequencies a wheelchair occupant would be exposed to while riding on simulated rough terrain. A novel dummy was instrumented with accelerometers to measure the accelerations and frequencies experienced by the wheelchair user. The apparatus and method was able to detect peak acceleration magnitudes, and was able to detect resonant frequencies and their intensities with either a PSD or FFT analysis. The minimum observable effect of change between two test conditions ranged from 6.0% for peak acceleration analysis when using six tests and a light dummy; to 41.0% for PSD analysis when using three tests and a heavy dummy. This adjustable testing apparatus and method can be used to tune a wheelchair system suspension design because it can elucidate whether or not a design is able to reduce accelerations and attenuate resonant frequencies experienced by a wheelchair occupant. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2010-01-30 12:17:57.181

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Suspensions play a crucial role in vehicle comfort and stability. Different types of suspensions have been proposed to fulfill the essential characteristics of vehicle suspensions. A semi-active suspension with adjustable damper improves the performance of a suspension in different conditions and it is better than a passive suspension in terms of ride comfort and handling. Furthermore, it is not as expensive and complicated as an active suspension. Semi-active suspensions rely on adjustable damping coefficient. A new type of air suspension with independent ride height and stiffness tuning has been developed recently. By using two air chambers in the suspension system, ride height of vehicle and stiffness of suspension can be adjusted independently and simultaneously. The conventional air suspension systems use compressor to pump the air into a single flexible rubber airbag and by inflating the air, the chassis will be raised from the axle (ride height control). In this type of suspensions, the stiffness of spring is not under control. In the new air suspension system, by controlling the air pressure on both chambers, one can tune the suspension stiffness and the ride height of the vehicle at the same time for different driving conditions. The air suspension is also able to maintain the vehicle body at the same height and natural frequency for different load or number of passengers. This thesis discusses about the design analysis of an air suspension with ride height and stiffness tuning. The analytical formulation is developed for the optimum design of the new air suspension system. In this thesis, the interconnection between the pressurized chambers of the new air suspension with ride height and stiffness tuning is studied to further improve the performance. Proper interconnection of air springs can help the suspension system to distribute the load between tires more evenly on rough roads or uneven surfaces. Different configurations in air spring interconnection have different impact on the handling and tire load distribution. To study the effect of air spring interconnection configurations on tires load distribution and vehicle handling, a general mathematical model is developed. This model is used to compare various configurations in detail. Results show that interconnection could improve tire load distributions greatly. It is also shown that improving tire load distribution will deteriorate roll stiffness that in turn deteriorate vehicle handling at higher speeds. Since on rough roads, vehicle’s speed is necessarily low, interconnection will not have adverse effects on vehicle handling when activated.