Digital Human Modeling for Long, and Low-Volume Assembly Processes: Gas Turbine Assembly Case Study

Musculoskeletal disorders (MSDs) are prevalent among workers in industrialized countries, reducing productivity, affecting business profitability, and causing personal discomfort. Poor workplace design is a key contributing factor to the phenomenon. The Digital Human Modeling (DHM) approach, initially developed and primarily used for large-scale, repetitive production environments, facilitates the early identification of potential risks associated with tasks in design situations. This paper aims to investigate the extent to which existing Digital Human Modeling (DHM) tools, such as Jack 7.1, can accurately assess ergonomic risks in long, low-volume assembly processes. To this end, a single case involving the work of tightening in a position above the heart, as part of the assembly of gas turbines in a restricted space, was analyzed using Jack 7.1. The work system was simulated in JACK 7.1 and the Predetermined Time Standard tool based on MTM-1, included in the software, was used for time calculations. The rest allowances were calculated in accordance with the guidelines set forth by the International Labour Office and Kanawaty (1996). The MSD risk assessment for over-the-heart work was performed in two phases: initially, a simulation and RULA ergonomic analysis in JACK 7.1, followed by additional ergonomic evaluations using the OCRA Index and KIM-MHO. This paper concludes that JACK 7.1 can be used to analyze ergonomic risks in long, and low-volume assembly processes. However, the analysis needs to be completed using other methods not available in the software, such as the OCRA Index and KIM-MHO.