Instrumented undriven steering wheel to illustrate dynamic behavior of vehicles

In this paper, a low-cost dynamometer for undriven, steered wheels is described.  The dynamometer was produced to determine whether such an instrumented mechanism is practical.  Four S-beam load cells and two opto-counters were used to obtain all moments, forces, and points of their application.  Overturning, aligning, and rolling resistance moments besides vertical force are directly measured by the load cells.  The opto-counters detect wheel angular velocity and steering angle.  The dynamometer evaluation results showed significant correlation between expected values and measured data with high accuracy.  Wheel dynamic behavior can be defined according to dynamic and kinematic analysis in which relative calculations have minimum simplifying assumptions.   Keywords: dynamometer, wheel forces and moments, point of force application, load cell, opto-counte

Prediction Of Lateral Force In An Off-Road Tire As A Function Of Seven Variables Using Response Surface Methodology (RSM)

In this study an in-situ Single Wheel Tester (iSWT) was used to investigate the effect of some of the most important independent variables on the lateral force of a high lug agricultural tire. The variables include some soil parameters and tire characteristics. Response Surface Methodology (RSM) also was used to construct a design of experiment and propose the lateral force model as a function of seven variables (various combination treatments of soil characteristics and tire parameters). A total of 152 experimental tests were conducted to find appropriate model. Reduced form of a quadratic model was selected to predict the tire lateral force (R2 > 0.9). The results show that the side slip angle and moisture content had major and minimal effect on tire lateral force respectively. Increasing the tire normal load, not only increases the maximum value of tire lateral force attainment, it also pushes the peak value of the lateral force to higher slip angles

Developing new mathematical model formats for estimating daily and monthly solar radiation: case study: Iran

Although a few numbers of studies are conducted for estimating in different cities of Iran, updating and developing new models based on more recent data are necessary. Six cities with different climate conditions were selected. Five newly developed daily and eight newly developed monthly model formats were fitted to measured data of Iranian cities. Seven statistical parameters were calculated to investigate the performances of models. To prove the excellence of the newly developed models compared to the performance of available models, four available daily models were fitted to daily measured data. Furthermore, to prove the generality of newly introduced formats in the present study, four foreign cities around the world were selected to use newly introduced model formats. Newly developed model formats have an extremely good and significant performance at 1% probability level. Furthermore, for Iranian cities, compared to available daily formats, newly introduced formats have shown to have better performances in most cases