| This doctoral dissertation provides a succinct compilation of research related to analysis of stress and displacement in an aluminum alloy automobile rim. Exhaustively detailed and elaborately discussed are: (a) measurement of strain on the rim under known loading conditions, (b) development of finite element models using the ALGOR finite element system, (c) the influence of opening location and geometry on mechanical performance of the rim. Experimental observations are compared with finite element analysis results. In particular, experimental strain measurements on a rim under the influence of a radial load are compared with predictions of an analytical model developed using ALGOR. Finite element analysis modeling of rim response under the conjoint influence of radial load and inflation pressure is critically examined and discussed. The influence of optimizing opening geometry so as to induce minimum of stress concentration is highlighted. The importance of establishing static loading conditions on the rim of a run-flat tire for purposes of achieving optimum mechanical performance is also elucidated. The role of environment in exacerbating degradation of the metal rim and its concomitant influence on mechanical response and wheel performance is briefly discussed.; The various aspects, both elucidated and discussed at length in this document, have helped accomplish the objectives of this study on evaluating the conjoint influence of tire inflation and loads on stress and mechanical response of automobile rims. Current automobile rims are primarily designed for conventional air-supporting tires having standard inflation. The development and emergence of a spectrum of run-flat tires, having stiff sidewalls and bead areas has made possible the safe and efficient operation of a wheel at inflation pressures approaching and even equal to zero. This has necessitated the need to conduct a stress analysis on an automobile rim under the influence of various load conditions. Possible loading conditions on the metal rim are: (a) pressure due to inflation, (b) radial loading on the bead seat resulting from the weight of the automobile, and (c) local bending moments induced on the rim due to an offset. These are directly influenced by the width of the rim, as existing run flat tires perform best on the widest possible rim for a given tire size. Besides, it is essential to explore options of providing an opening in the rim, other than those openings provided for the valve, in order to facilitate the mounting of pressure sensor devices. Through a combination of carefully orchestrated and monitored experimental tests and analytical studies, the size, shape and precise location of the opening was determined. Results of this study are bound to have an impact on the design and development of rims for automobiles of the both the near and distant future. |
