Ergonomic Evaluation of Billet Mould Maintenance Using Hierarchical Task Analysis, Biomechanical Modeling and Digital Human Modeling

ABSTRACT

Work related musculoskeletal disorders (MSD) are common in maintenance tasks arising out of man-machine incompatibility. A hybrid methodology integrating hierarchical task analysis (HTA), posture analysis (REBA), biomechanical modeling, and digital human modeling (DHM) is sequentially applied to a mould maintenance job. Among the 29 tasks identified using HTA, 5 tasks namely ‘striking with mallet’, ‘positioning oiler plate’, ‘fastening oiler plate’, ‘positioning top plate’, ‘fastening top plate’ are under ‘high severity’ category based on REBA scores. From biomechanical modeling, it is observed that all the five L5/S1 peak loading values corresponding to dynamic analysis (4069 – 5701 N) and most of the peak loading values corresponding to static analysis (2948 – 5707 N) exceed the threshold (e.g. NIOSH 3400 N). The workstation for the maintenance job is redesigned using DHM. The new design has reduced the compressive force at L5/S1 from 2948 - 5707 N to 2010 - 2637 N.

GRAPHICAL ABSTRACT

Keywords:

• hierarchical task analysis
• biomechanics
• digital human modeling
• steel industry

ACKNOWLEDGMENT

The authors appreciate the efforts provided by Dr O B Krishna, and all of the workplace personnel involved during the field study.