Mahesh Bhiwapurkar
@opju.ac.in
Professor, Mechanical Engineering Department
Professor
RESEARCH, TEACHING, or OTHER INTERESTS
Engineering, Multidisciplinary
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Prakash Kumar Sen, Mahesh Bhiwapurkar, and S.P. Harsha
Elsevier BV
Anurag Vijaywargiya, Mahesh K Bhiwapurkar, and A. Thirugnanam
Nepal Journals Online (JOL)
Introduction: Manual lifting operations continue to play a key role in the industrial and service sectors, inflicting physical strain on the musculoskeletal system, despite advances in automation. As a result, an experiment is carried out to assess the impact of two lifting task parameters; weight and height, based on the estimation of subjective responses and biomechanical loading, while lifting the weight symmetrically in the sagittal plane. Also to recommend the safe limit for manual lifting tasks. Methods: Twelve volunteer male students in the age group of 21 to 26 years performed lifting tasks from floor to 5 different heights (below the knee to ear level), with 5 different weights (10 to 20 kg) using free-style lifting techniques. The load pan with no handle was used for lifting weight, which is typically adopted in the Indian building construction field. The subjective estimate was obtained using workload assessment by body discomfort chart. The biomechanical loading (loading rate) for each lifted weight and height was collected using a force platform. Results: The results showed that heavier weights produced higher stresses than lower weights. The loading rate was found to be almost similar at waist or knee level. The loading rate was observed to be linearly increasing after waist level. The overall workload rating seems to be a good correlate with the mean loading rate to some extent. Conclusion: It is proposed to keep the maximum acceptable lifting weight from floor to knee, up to the ear level is 15 kg, to prevent any musculoskeletal or chronic injury.
Prakash Kumar Sen, Mahesh Bhiwapurkar, and S. P. Harsha
Springer Nature Singapore
Prakash Kumar Sen, Mahesh Bhiwapurkar, and S.P. Harsha
Elsevier BV
Prakash Kumar Sen, Mahesh Bhiwapurkar, and S.P Harsha
Elsevier BV
Prakash Kumar Sen, Mahesh Bhiwapurkar, and S P Harsha
IOP Publishing
Abstract At wheel track contact point, the high stress concentration, poor weld quality, and heterogeneity of weld material are the main factors that cause fatigue crack on any rail weld. Railway network agencies are concerned about the safety of the railway track when it comes to detecting and fixing weld faults to avoid vehicle derailment and loss of lives. This study analysed a numerical simulation of fatigue crack and its evolution under loaded service condition. A 3-D CAD wheel rail weld assembly model was built to study an AT welded joint under fatigue, and for stress concentration factor (SIF) calculation. The results are found by inserting a semi elliptical crack on the rail weld head surface with ANSYS, and then numerical simulation has been performed to get the different three modes of SIF at rail weld crack. The analysis findings data was recorded with critical fracture parameters of SIFs and its number of cycles to failure using LEFM technique and respective results have been plotted. With ANSYS the stress intensity on a crack will be resulted. By using numerical method, the critical crack size and number of cycle load with fatigue life of rail would be determined. The numbers of rail weld inspection per year has been determine by using the maximum number of cycle. The aim of this paper is to develop an effective inspection and maintenance frequency based on rolling contact surfaces crack propagation analyse. This will help to prevent the occurrence of rail failure by taking the required action at the right time, and extend the rail life expectancy, reduce the rail maintenance work and its cost.
Prakash Kumar Sen, Mahesh Bhiwapurkar, and S P Harsha
IOP Publishing
Abstract The Free vibration response of the Railway track is an important area in the design of the Rail and its joints to improve the ride comfort of the passengers. In this study, the rail weld considered is alumino thermite weldment used in majority of Indian Railways network. This paper aims at the study of the vibration response of rail wheel assembly having an AT weld on as a rail joint subjected to free vibration and to find the Natural frequencies of vibration and mode shapes. The geometric model of rail and weldment with wheel and axle components is modelled using Space-claim which is a part of ANSYS package and analysed using numerical simulation package ANSYS 2020 Workbench. In this work, free vibration analysis or modal analysis of the rail weld is carried out to extract the first few modes of vibration. The Natural frequencies obtained along with the corresponding mode shapes of the rail weldment show that they are within the permissible range specified by the standards of railway department also for better ride comfort of the passenger.
Prakash Kumar Sen, Mahesh Bhiwapurkar, and S. P. Harsha
Springer Singapore
Prakash Kumar Sen, Mahesh Bhiwapurkar, and S. P. Harsha
Springer Singapore
Mahesh Bhiwapurkar
Springer Singapore
Anurag Vijaywargiya and Mahesh Bhiwapurkar
Springer Singapore
MK Bhiwapurkar, VH Saran, and SP Harsha
SAGE Publications
An experimental study has been conducted on the vibration simulator, developed as a mockup of a railway vehicle. In this paper, the effect of variations in the posture and vibration magnitude on head motions in three translational directions (fore-and-aft, lateral and vertical) are studied with seat vibration in fore-and-aft direction. Thirty healthy male subjects are exposed to random vibration with three vibration magnitudes of 0.4, 0.8 and 1.2 m/s2 r.m.s. over the frequency range 1–20 Hz. The data results are analyzed in terms of seat-to-head transmissibility (STHT) in two sitting postures; backrest and forward lean. Vibration measurements of the head motions are made with an apparatus (bite-bar). The study confirms that the measured responses to single fore-and-aft axis vibration have shown notable cross-axis responses. An increase in the excitation magnitude consistently revealed a decrease in the response peak magnitude and the corresponding resonant frequency, particularly in the presence of a back support. Such non-linear behavior has been interpreted as a non-linear softening effect in the muscle tension under increasing intensity of vibration. The use of a back support significantly alters the biodynamic responses of the seated body, which is attributable to the constraint due to the backrest support.
Mahesh K. Bhiwapurkar, V. H. Saran, and Suraj P. Harsha
International Institute of Acoustics and Vibration (IIAV)
The low frequency vibration transmitted to the body can affect the comfort, performance, and health of humans. In this paper, the effect of variations in posture and vibration magnitude on the head motion in three translational axes (fore-and-aft, lateral and vertical) has been studied with a vertical seat vibration. Thirty healthy male subjects were exposed to random vibration with three vibration magnitudes of 0.4, 0.8, and 1.2 m/s2 rms over the frequency range of 1–20 Hz. The results are analysed in terms of seat-to-head-transmissibility (STHT) for the head motions in two seated postures (backrest and leaning forward on table). The measurement of the head motion was made with an apparatus (bite-bar) specifically developed for this purpose. The measured responses to a single axis seat vibration have also shown notable cross-axis responses in both vertical and fore-and-aft axes for both postures. The crossaxis fore-aft and vertical STHT responses showed single peak near 5 Hz in both postures. An increasing intensity of vibration yields a non-linear softening effect in the muscle tension, particularly in the presence of back support, however, the body stiffens under a greater upper body motion in the forward leaning posture. The combined effect of the unsupported back and hands support was observed to be more pronounced around the resonance peak in the forward lean posture.
Mahesh K. Bhiwapurkar, V.H. Saran, and S.P. Harsha
Inderscience Publishers
Train passengers often experience difficulty in performing various sedentary activities such as writing during travel. This study identifies the influence of three primary parameters viz., vibration level, vibration direction and sitting posture on writing performance for an improved activity comfort in trains. Therefore, an experimental study was conducted on a mock up of rail vehicle to examine the interference in writing task under random vibrations excited in mono, dual and multi axis in low frequency range of 1-20 Hz at 0.4, 0.8 and 1.2 m/s2 amplitudes. Thirty healthy male subjects were assigned the task to write the given characters in two seated postures (on lap and table posture). The performance was evaluated subjectively using Borg's CR-10 scale and quantifying the distortion in writing. The results revealed that the degradation in writing performance was found to increase with vibration stimuli and reported maximum in both lateral and vertical direction equally. Similarly, the effects of multi axis vibration were found similar to dual axes vibration and greater than mono axes vibration. While higher degradation in performance was found while working on lap than on table in X-direction, however, all other mono and multi axis vibration reported maximum in table posture.
Mahesh K. Bhiwapurkar, V.H. Saran, and S.P. Harsha
Inderscience Publishers
In an attempt to define how train vibration and motion affect passenger comfort, an experimental study has been conducted to show the effect of variations in posture and vibration magnitude on head motion in three translational directions (fore-and-aft, lateral and vertical) with seat vibration in lateral direction. Thirty healthy male subjects were exposed to random vibration in lateral axis with three excitation magnitudes of 0.4, 0.8 and 1.2 m/s2 rms over the frequency range of 1-20 Hz. The data results are analysed in terms of seat-to-head-transmissibility response, phase and coherence for head motions in two sitting postures (backrest and forward lean). The seat-to-head-transmissibility response registered maximum head motion in lateral direction with single peak at 2 Hz in both the sitting posture. The response also reported an additional peak near 6 Hz in forward lean postures. The broad peak converged to a single peak at 2 Hz with reduction in seat-to-head-transmissibility response under the higher magnitude of lateral vibration, which was attributed to the softening effect of the human body. The STHT response yields only minimal effect on posture, particularly in the vicinity of the resonance only.
M. K. Bhiwapurkar, V. H. Saran, and S. P. Harsha
International Institute of Acoustics and Vibration (IIAV)
There is increasing use of laptop computer in rail vehicles for performing various sedentary activities such as reading and typing. The vibration is a major factor influencing the reading performance during the journey. Therefore, an experimental study was conducted to investigate the extent of interference perceived in reading an e-paper in two seated postures (backrest support and leaning over the table) under random vibration. The study involved 30 healthy male subjects who were excited with vibration acceleration in mono-, dual, and multi-axes in 1–20 Hz at 0.4, 0.8, and 1.2 m/s amplitudes. The task consisted of reading the given paragraph of an e-paper under various vibration stimuli, and it was evaluated by time taken to complete the task and subjective evaluation of reading difficulty. The subjective evaluation showed that the reading difficulty increased with vibration stimuli for both the subject postures. The subjects perceived higher difficulty and degradation in reading performance for vibration in dual and multi-axes, which was comparable to that for lateral and vertical directions also. The perceived difficulty and impairment in reading performance was greater while reading with the laptop on their lap for vibration in the x-axis, while the effect was just the reverse for other axes.
M.K. Bhiwapurkar, V.H. Saran, and S.P. Harsha
Elsevier BV
M.K. BHIWAPURKAR, V.H. SARAN, and S.P. HARSHA
National Institute of Industrial Health
Performance of sedentary activities such as reading and writing, in trains is known to be affected by the vibrations. An experimental study was therefore initiated to investigate the interference perceived in sketching task under low frequency random vibration in both mono and dual axes. Thirty healthy male subjects participated in the study. Random vibration stimuli were excited in various axes in frequency range of 1-20 Hz at magnitudes of 0.4, 0.8 and 1.2 m/s(2). The task required the subjects to sketch the given geometric figures such as circle, rectangle and triangle under vibration environment in two subject postures (sketch pad on lap and on table). Three performance methods were used to measure the effect of vibration stimuli and posture. They consisted of two specifically designed objective methods for percentage distortion measurement and one subjective method using Borg CR10 scale. The results revealed that the percentage distortion and difficulty in sketching increased with an increase in vibration magnitude and was found to be higher for vibration in Y- and Z-axis. Similar trend was observed for percentage distortion and difficulty in sketching for dual axes also. The perceived difficulty and impairment in sketching performance was greater while sketching on lap for X-axis, while the effect was just the reverse for other axes.
M K Bhiwapurkar, V H Saran, S P Harsha, V K Goel, and M Berg
SAGE Publications
Whole-body vibrations in trains are known to affect the performance of sedentary activities such as reading, writing, sketching, working on a computer, etc. The objective of the study was to investigate the extent of disturbance perceived in sketching task by seated subjects in two postures under mono- and multi-axis Gaussian random vibration environment. The study involved 21 healthy male subjects in the age group of 23—32 years. Random vibrations were generated both in mono- and multi-axial directions in the frequency range of 1—10 Hz at 0.5, 1.0, and 1.5 m/s2 rms (root mean square) amplitude. The subjects were required to sketch given geometric figures such as a circle, triangle, rectangle, and square with the help of ball-point pen under given vibration stimuli in two postures (sketch pad on lap and sketch pad on table). The deviation in distortion with respect to the given figure is represented in terms of percentage distortion. The influence of vibrations on the sketching activity was investigated both subjectively and by two specifically designed objective methods, namely, RMS (root mean square methodology) and area methods. The judgements of perceived difficulty to sketch were rated using seven-point semantic judgement scale. The percentage distortion and difficulty in sketching activity increased with an increase in vibration magnitude. Both subjective evaluation and the RMS method revealed that the task was affected more while sketching on the table. The percentage distortion was affected similarly and maximum in all the vibration directions except for the vertical, while sketching difficulty was found to be higher only with longitudinal and multi-axis vibration direction. The subjective evaluation also revealed that there was no effect of the type of entity chosen on the sketching difficulty.
M.K. BHIWAPURKAR, V.H. SARAN, S.P. HARSHA, V.K. GOEL, and Mats BERG
National Institute of Industrial Health
Recent studies on train passengers' activities found that many passengers were engaged in some form of work, e.g., reading and writing, while traveling by train. A majority of the passengers reported that their activities were disturbed by vibrations or motions during traveling. A laboratory study was therefore set up to study how low-frequency random vibrations influence the difficulty to read. The study involved 18 healthy male subjects of 23 to 32 yr of age group. Random vibrations were applied in the frequency range (1-10 Hz) at 0.5, 1.0 and 1.5 m/s(2) rms amplitude along three directions (longitudinal, lateral and vertical). The effect of vibration on reading activity was investigated by giving a word chain in two different font types (Times New Roman and Arial) and three different sizes (10, 12 and 14 points) of font for each type. Subjects performed reading tasks under two sitting positions (with backrest support and leaning over a table). The judgments of perceived difficulty to read were rated using 7-point discomfort judging scale. The result shows that reading difficulty increases with increasing vibration magnitudes and found to be maximum in longitudinal direction, but with leaning over a table position. In comparison with Times New Roman type and sizes of font, subjects perceived less difficulty with Arial type for all font sizes under all vibration magnitude.