With recent advancements in the production of plastic materials the use of woven plastic webbings (Nylon, Polyester, etc) has increased due to decreased cost, increased load rating, greater ease of use over chains, and an increasingly proven history of use. However a common misconception is that chains and plastic webbing can be interchanged as long as the webbing has a sufficient load rating.
Packages in transport are commonly secured by an arrangement of rigid blocks (chock blocks) at the base and chains, cables, or straps to the top. Analysts are apt to evaluate restraint loads by distributing the prescribed shipping loads based on relatively simple free body diagrams, assuming rigid body mechanics. However, due to the lower stiffness of plastic webbing these rigid body assumptions are not always valid, and may lead to incorrect or misleading results.