Simplified Design of Falling Object Protective Structures

Mobile equipment operators in surface and underground mines are protected against falling objects by a canopy over the operator’s seat. Designing a structurally safe canopy poses challenges to the design engineer because of a number of assumptions that have to be made in establishing rational design criteria. This paper investigates the design and analysis of falling object protective structures (FOPSs) by proposing a method of energy balance between falling objects and a structure. Elastic and inelastic responses of the structure are considered. The structure is assumed to be supported on springs, simulating the elasticity of the equipment chassis and rubber tires. This realistic assumption results in significant reductions of the impact force on the canopy and supports. It is concluded that these canopies should be designed with column supports that incorporate springs. The design methodology is illustrated by solving a numerical example.