In the era of Industry 4.0, digital human modeling (DHM) may be the key to improving ergonomics related to manual operations in the workplace. Poor workplace ergonomics may lead to reduced work productivity and an increased risk of health problems among employees, resulting in actual losses for enterprises, e.g., sickness absence, employee turnover, and training. DHM technology can help speed up ergonomic analysis and improvement. This paper proposes a methodological framework based on DHM to improve ergonomics in the workplace. Its purpose is to provide practitioners with an easy and detailed approach to ergonomics assessment and improvement procedures. The framework developed two main stages: the workplace Research Stage and the DHM and Simulation Stage, which cover the eight detailed steps of an effective DHM-based ergonomic assessment together. A case study was used to verify and demonstrate the effectiveness of the proposed methodological framework.

Results of mathematical modelling and computer simulation of transient processes in the turbine jet engine SO-3 have been presented. The transient processes result from two different fault conditions. In the first case, the transient process has been induced with a rapid fuel shut-off. In the second case, the transient process follows some failure to the shaft that connects the turbine rotor to that of the compressor. The failure occurred in the area of the middle engine bearing support.

The effect of processes of accumulating mass and enthalpy of the working medium on the dynamics of transient processes thereof is often discussed in scientific publications on the mathematical modelling of turbine engines (treated as systems that undergo control and automatic adjustment). The paper is intended to make a comparison between findings gained from simulation carried out with two alternative models of an aircraft turbine engine (of the S0-3 type). The first model takes account of the dynamics of the processes of accumulating mass and energy of the working medium within the combustion-chamber volume and that of the convergent nozzle. The second, simplified model, neglects the dynamics of the processes of accumulating mass and energy of the working medium, since it has been assumed that it is the dynamics of the kinetic-energy accumulation in the rotor mass that predominates in various representations of transient processes. To conduct simulation-based experiments, each of the alternative models of an engine was connected to a special simulation unit, which simulated operation of fuel supply and control systems. Two rounds of experiments were carried out. The first one was intended to facilitate observations of transient processes effected with quick shifting of a control lever from the idle position to that of full thrust, and back. In the second round observed were processes resulting from changes in the critical jet area. The second, alternative model was used to investigate the effect of ever-greater hypothetical volumes of the nozzle on how the transient processes proceeded. It has been found that in the case of the S0-3 engine, low nozzle capacity remains of only slight effect on how the transient processes proceed. Hence, simplified modelling methodology is fully justified.