System Dynamics Model Application for Ergonomic Assessment of Manual Material Handling Tasks

Abstract

Despite increased levels of automation in manufacturing occupations in recent years, many activities are still performed through human intervention and involve Manual Material Handling (MMH), thus exposing workers to stress due to over-exertion and potential Work-Related Musculoskeletal Disorders (WRMSDs). An early ergonomic and physical demand assessment of work activities is critical to reducing exposure to risk and to maintaining desired levels of productivity. Biomechanics consists of applying concepts of static and dynamic equilibrium to different parts of the human musculoskeletal system using free-body diagrams to estimate muscle force and loads generated across the joints and tissues. System dynamics is a powerful tool applied in resolving complex problems with different influencing variables. This technique can help designers and managers to understand, evaluate and simulate the factors causing problems in the system. This paper presents the application of System Dynamics modeling to assess the biomechanical risks associated with manual material handling tasks. The case study presents predicted cumulative biomechanical compressive loads from material handling task and can assist project managers to understand and reduce exposure to ergonomic risks in the workplace.