Value which shows how much bending stress can be exerted on a structural member. The more resistance, the higher the modulus. Section modulus differs with the size and shape of a structural member. The same type of member will have a higher section modulus if it is heavier than the same type of member which is lighter because the heavier one will be stiffer.
A measure of a frame's strength based entirely upon the height, width, thickness, and configuration of the side rails. This is calculated at the point of maximum stress, generally directly behind the cab. The measurement can only be used to compare frames of like materials, not material strength.