Bending Strength Essay
This is the first body requirement and its task is to support all the vehicle subsystems. The body in static is going to suffer bending due to the weight of the components, passengers, fuel and cargo, Figure 42. Similar to a beam simple supported, the very first requirement is that the structure bend sufficient to absorb the energy due to the weight, but has to withstand the weight under different loading scenarios. Figure 42: Body loading under a static scenario and its corresponding Shear and Moment diagrams.
Utilizing beam simple analysis the Shear and Moment diagrams can be obtained. These diagrams are dependent on the location of the center of gravity (CG) of the subsystems. Those locations are at the same …show more content…
This test is called H-point bending test and consist of mounting a body into a ball and socket fixtures located in the FR and RR struts (Figure 44). Thereafter a bar applied the load at the H-points (situated at the seat fixtures of in the top of the rocker) with gradual increments, until it reaches the maximum load. For each grade, the amount of deflection is recorded on a load-deflection graph. To confirm the maximum load which the body is not deformed permanently loading and unloading cycles are conducted during the test. The slope of the curve in the load-deflection graph will be as a result, the stiffness of the body (Malen 2011 p.124). Figure 44: H-point bending test convention (Malen, 2011)
Bending Stiffness requirement
Consider the body idealized as a simple beam loaded at its center span and the supporting points are in the suspension (Figure 45) as an analogy of H-point bending test of Figure 44. Figure 45: Simple supported beam for static test
By applying the load, the body reacts in opposition to be bent. If this opposition is low, the distance of bending δ will be higher and consequently the bending angle α. This opposition depends on the wheelbase l and the section bending stiffness EI. Those are related by the equations: