Faculty Publications
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Item Ergonomic Assessment of Musculoskeletal Disorders Among Surface Mine Workers in India(Springer Science and Business Media Deutschland GmbH, 2021) Jeripotula, S.K.; Mangalpady, M.; Raj, G.R.Injuries due to work-related musculoskeletal disorders (WMSDs) are not uncommon in heavy industry like mining. Researchers acknowledged that occupational exposure to ergonomic risk factors is the chief causative factor in the development of WMSDs. The aim of this study was to perform an ergonomic assessment of musculoskeletal disorders among surface mine workers in India. Standardized Nordic Questionnaire was used to collect subjective response from 500 workers. A stratified random sampling method according to surface mining work activity type was used to obtain the sample. Data was collected by means of a structured questionnaire, and the Statistical Package for Social Sciences (SPSS) was used to analyze data using descriptive and inferential statistical methods. A response rate of 85% was obtained out of 500 targeted groups. The WMSDs prevalence for the 12-month period was estimated to be 44.23%. The mean and standard deviation of workers’ age were 41.31and 8.927, respectively. The study has shown that the operators of dumpers, dozers, and graders along with electricians were found to be the most susceptible to develop WMSD problems. Among the most affected body parts, back disorder reported the highest. Further, it was found that working with static posture over the longer duration has a significant association with the lower back disorder (with p = 0.020) and bouncing and jarring has also significantly associated with the lower back disorder (with p = 0.023). Similarly, a significant association was found between repetitive work and neck pain (with p = 0.016). The study depicted a significant association between ergonomic hazards and WMSDs, like working with prolonged static posture, bouncing and jarring, and repetitive work. © 2020, Society for Mining, Metallurgy & Exploration Inc.Item Postural analysis of dumper operators and construction workers – a case study(Books and Journals Private Ltd., 2021) Kunar, B.M.; Mangalpady, M.; Kar, M.B.This case study aims at assessing and understanding the level of ergonomics in manual material handling tasks (loading, granite cutting, concrete mixing, brickwork, and plastering) of civil construction workers and dump truck drivers working in Indian opencast mines. The study involves the determination of the level of musculoskeletal disorder and predicting the most affected body parts due to incorrect working posture. The comprehensive methodology involved in this study includes rapid upper limb assessment (RULA) and rapid entire body assessment (REBA) techniques to find the risk involved in the working posture of the construction workers and dump truck drivers. The study showed that posture adopted in civil construction work and dump truck operators (loading and unloading task) are ergonomically incorrect and may cause musculoskeletal disorder (MSD) related problems in the future. This study also showed that the trunk and wrist are the most affected parts of the body in construction workers and the neck and wrist in case of the dumper operator while performing different tasks. © 2021, Books and Journals Private Ltd.. All rights reserved.Item Evaluating the Whole-Body Vibration Exposure in Rock Breaker Operators: Influence of Rock Type and Operational Parameters(Informatics Publishing Limited, 2024) Vikram, P.; Mangalpady, M.; Ariff, S.This study aims to evaluate the Whole-Body Vibration (WBV) exposure of rock breaker operators in surface mining, focusing on limestone, banded hematite quartzite, and granite gneiss rocks. Using a seat pad tri-axial accelerometer, operators were monitored across varying impact powers, Rock Mass Cuttability Index (RMCI), and net breaking rate (NBR). Results indicate that operators exceeded the Exposure Action Value (EAV) of 0.5 m/s2and the Vibration Dose Value (VDV) of 9.1 m/s1.75 while operating in limestone and granite gneiss rocks. Moreover, hydraulic rock breaker operators surpassed the Exposure Limit Value (ELV) of 1.15 m/s2and the VDV of 21 m/s1.75for the granite gneiss rocks, based on A(8) and VDV(8) derived limits. Notably, operators breaking banded hematite quartzite rocks experienced lower vibration amplification. RMCI and impact power emerged as critical factors in WBV exposure, underscoring the need for optimal settings to mitigate excessive vibrations. These findings underscore the importance of managing WBV for operator health and safety in surface mining operations. © 2024, Informatics Publishing Limited. All rights reserved.Item Development, optimization, and prototyping of a simplified sit-stand mechanism for lower limb impairments(Springer Science and Business Media Deutschland GmbH, 2025) George, S.P.; Thomas, M.J.; Mathew, M.; Gangadharan, N.; Varghese, A.K.A sit-stand device for rehabilitation should be simple in its design, easy to manufacture, and convenient for individuals with mobility impairments to use. This paper proposes a design framework and prototyping process for developing an assisted sit-to-stand mechanism tailored to the specific limitations faced by individuals with lower limb impairments. The study incorporates a functional kinematic and kinetic design to ensure the mechanism’s usability across a diverse range of individuals. Recognizing the critical challenges faced by individuals with spinal cord injuries (SCI) and subsequent paralysis, the design philosophy integrates considerations specifically aimed at this population. A simplified circular design trajectory is presented for individuals with muscle paralysis, focusing on the synthesis of an electrically actuated mechanism. A four-bar linkage is modeled to represent the mechanism in the sagittal plane. The functional attributes of the device are determined, and kinematic synthesis is performed to ensure comfort during the sit-to-stand motion. This is achieved by minimizing the actuator’s travel distance during the lift. The velocity and acceleration profiles of the linear actuator are determined after applying boundary conditions. An optimal configuration is selected based on minimizing the displacement of the electric actuator. A human body model based on a 50th percentile male was developed to simulate a motion study of the sit-stand and validate the trajectory using the motion study module in SOLIDWORKS™. An optimum sit-to-stand linkage design was synthesized, and the corresponding prototype was fabricated. The independent anthropometric dimensions on which the design depends are the thigh length and the weight. The sagittal linkages for lifting were calculated and tested through simulation with a human body model to replicate the sit-to-stand movement. The prototype was evaluated on an able-bodied individual. A key design feature was the repositioning of support from the armpit to the hip, thereby reducing user discomfort and improving ergonomics. The motion study revealed that the trajectory of the hip joint (H-point) followed a nearly circular curvature. Stability analysis using a mannequin confirmed a static stability margin of 1 and showed that the device would tip forward only if the deceleration exceeded 35.8 m/s2, which is significantly higher than typical human-induced accelerations—indicating safe operation during use. The prototype fabricated demonstrated the intended sit-to-stand functionality and validated the design approach. The motion analysis confirmed ergonomic hip support and smooth joint trajectories. While the initial testing was successful on an able-bodied subject, further evaluation involving individuals with spinal cord injuries is recommended for final adjustments. This work presents a cost-effective and customizable framework for manufacturing sit-to-stand assistive devices, scalable for variations in body weight and thigh length. © International Federation for Medical and Biological Engineering 2025.Item Assessment of whole-body vibration in hydraulic rock breaker operators based on operating parameters(Springer Nature, 2025) Vikram, P.; Mangalpady, M.; Tripathi, A.K.; Ariff, S.; Cherie, A.The study evaluates the impact of whole-body vibration (WBV) on rockbreaker operators in Indian mechanized quarries. The study was performed on three different operating parameters scenario with varied power and rate such as Operating parameter-(1) Impact power 37.25 HP with impact rate of 420–450 blows/min, Operating parameter-(2) Impact power 43 HP with Impact rate of 350–375 blows/min and operating parameter-(3) Impact power equal to 54 HP with impact rate of 280–300 blows/min. WBV data was collected from five rockbreaker operators using a seat pad tri-axial accelerometer, across three different operating parameters. The results indicated that all the rockbreaker operators exceeded the A(8) based exposure action value (EAV) of 0.5 m/s2 in all the three operating parameters but all the rockbreaker operators in the third operating parameter have exceeded the A (8)-based exposure limit value (ELV) of 1.15 m/s2 and vibration dose value (VDV) based exposure limit value (EAV) of 9.1 m/s1.75. The study’s findings suggest that the vibration amplification for operators working in operating parameter-1 was reduced completely compared to those working in the second and third operating parameters, based on the above “Health Guidance Caution Zone (HGCZ)” for daily vibration exposure, specifically A (8) and VDV (8) measurements, Based on the aforementioned observation, it can be inferred that operating parameter-1 is an advantageous setting, as it minimizes the vibration experienced by the rockbreaker operators. © The Author(s) 2025.