mohd farid aladdin - Academia.edu (original) (raw)

Papers by mohd farid aladdin

Research paper thumbnail of Perturbation effect of noise on overall feeling of discomfort from vertical whole-body vibration in vibro-acoustic environment

International Journal of Industrial Ergonomics, 2021

The human discomfort from combined noise and vibration has been investigated with a new perspecti... more The human discomfort from combined noise and vibration has been investigated with a new perspective. The concept in perturbation effect has been adopted to formulate a new novel predictive model of human discomfort from noise and vibration. A psycho-physics experiment has been designed to identify the perturbation effect which caused by noise stimulus. The experiment involved twelve (12) subjects. Each subject was imposed in random order with a total of 42 combinations of seven (7) levels of noise (X, 61, 71, 77, 84, 87, 89 dBA) where the X is no noise stimulus, and six (6) levels of vibration dose values (V1 = 0.2079, V2 = 0.3242 V3 = 0.6388 V4 = 0.8803 V5 = 1.4947 and V6 = 1.8624 m/s1.75). Initially, the subject would be imposed with a reference combination of noise and vibration which was assumed to have a value of 100. The assigned combination for reference was chosen at sound exposure level, LAE of 71 dB(A) and the vibration dose value, VDV of 0.2079 ms−1.75. Then the subject was imposed with other combinations of noise and vibration in a duration of 5 s and 5 s break in between the stimuli combination. After each exposure to each combination of noise and vibration, the subject is required to state the discomfort caused by the noise and vibration in the form of a number relative to the reference stimuli of 100. The subject was asked to be seated in a relaxed position, holding a handphone and used it to record all the response values after each stimulation. The finding suggested that the discomfort from vibration can be predicted with equation ψv=170.6082avdv0.6662 and the overall discomfort from noise and vibration is given by ψv−n=ψv+ψvε where the ε is the perturbation effect caused by noise stimulus.

Research paper thumbnail of In-situ Study of Seating Static Comfort in Passenger Vehicles

MATEC Web of Conferences

In today’s automotive market, comfort is huge selling point of a vehicle. Priority is given by bu... more In today’s automotive market, comfort is huge selling point of a vehicle. Priority is given by buyers to how comfortable a seat feels during purchase decisions. The measure of comfort is harmonious mix of many aspects such as human ergonomics and physiological factors. However, a gap still exists between objective and subjective measures due to lack of emphasis by past researchers. This is particularly obvious in the lumbar support feature that has still not been able to address the health problems related to driving. This project focuses on bridging the gap by giving users the ability to define true preferred posture in realistic settings. This is done by the creation of a apparatus that allows users to individually manipulate the seat contour for optimum support in more segments than just lumbar area. The experiment is performed in 3 parts, where in each part different segments of the apparatus are manipulatable (lumbar segment, sacral & thoracic segment, and all segments). Sixty ...

Research paper thumbnail of A study of vibration transmission on seated person in passenger vehicle

PROCEEDINGS OF THE INTERNATIONAL ENGINEERING RESEARCH CONFERENCE - 12TH EURECA 2019

Research paper thumbnail of Evaluation of Human Discomfort from Combined Noise and Whole-Body Vibration in Passenger Vehicle

International Journal of Automotive and Mechanical Engineering

Exposure to noise and whole-body vibration (WBV) has been a key element in determining comfort le... more Exposure to noise and whole-body vibration (WBV) has been a key element in determining comfort levels in transportation systems. In the automotive industry, researchers and engineers continuously work on reducing noise and vibration levels to minimize discomfort. Noise annoyance in vehicles results from structure-borne as well as air-borne noise from vehicle powertrain, tires and aeroacoustics. Whole-body vibration affects vehicle passenger comfort at the seat pan, back rest and feet. The objective of this research is to evaluate the comfort level of seated passengers in a vehicle from noise and whole-body vibration by considering both separate and combined modality. The noise and vibration data were recorded and analysed in two vehicles on the same highway road with four different speeds. The vibration exposure in vehicle were evaluated based on ISO2631-1:1997. Noise exposure was based on A-weighted sound pressure level. The combined discomfort on noise and vibration were quantifie...

Research paper thumbnail of Perturbation effect of noise on overall feeling of discomfort from vertical whole-body vibration in vibro-acoustic environment

International Journal of Industrial Ergonomics, 2021

The human discomfort from combined noise and vibration has been investigated with a new perspecti... more The human discomfort from combined noise and vibration has been investigated with a new perspective. The concept in perturbation effect has been adopted to formulate a new novel predictive model of human discomfort from noise and vibration. A psycho-physics experiment has been designed to identify the perturbation effect which caused by noise stimulus. The experiment involved twelve (12) subjects. Each subject was imposed in random order with a total of 42 combinations of seven (7) levels of noise (X, 61, 71, 77, 84, 87, 89 dBA) where the X is no noise stimulus, and six (6) levels of vibration dose values (V1 = 0.2079, V2 = 0.3242 V3 = 0.6388 V4 = 0.8803 V5 = 1.4947 and V6 = 1.8624 m/s1.75). Initially, the subject would be imposed with a reference combination of noise and vibration which was assumed to have a value of 100. The assigned combination for reference was chosen at sound exposure level, LAE of 71 dB(A) and the vibration dose value, VDV of 0.2079 ms−1.75. Then the subject was imposed with other combinations of noise and vibration in a duration of 5 s and 5 s break in between the stimuli combination. After each exposure to each combination of noise and vibration, the subject is required to state the discomfort caused by the noise and vibration in the form of a number relative to the reference stimuli of 100. The subject was asked to be seated in a relaxed position, holding a handphone and used it to record all the response values after each stimulation. The finding suggested that the discomfort from vibration can be predicted with equation ψv=170.6082avdv0.6662 and the overall discomfort from noise and vibration is given by ψv−n=ψv+ψvε where the ε is the perturbation effect caused by noise stimulus.

Research paper thumbnail of In-situ Study of Seating Static Comfort in Passenger Vehicles

MATEC Web of Conferences

In today’s automotive market, comfort is huge selling point of a vehicle. Priority is given by bu... more In today’s automotive market, comfort is huge selling point of a vehicle. Priority is given by buyers to how comfortable a seat feels during purchase decisions. The measure of comfort is harmonious mix of many aspects such as human ergonomics and physiological factors. However, a gap still exists between objective and subjective measures due to lack of emphasis by past researchers. This is particularly obvious in the lumbar support feature that has still not been able to address the health problems related to driving. This project focuses on bridging the gap by giving users the ability to define true preferred posture in realistic settings. This is done by the creation of a apparatus that allows users to individually manipulate the seat contour for optimum support in more segments than just lumbar area. The experiment is performed in 3 parts, where in each part different segments of the apparatus are manipulatable (lumbar segment, sacral & thoracic segment, and all segments). Sixty ...

Research paper thumbnail of A study of vibration transmission on seated person in passenger vehicle

PROCEEDINGS OF THE INTERNATIONAL ENGINEERING RESEARCH CONFERENCE - 12TH EURECA 2019

Research paper thumbnail of Evaluation of Human Discomfort from Combined Noise and Whole-Body Vibration in Passenger Vehicle

International Journal of Automotive and Mechanical Engineering

Exposure to noise and whole-body vibration (WBV) has been a key element in determining comfort le... more Exposure to noise and whole-body vibration (WBV) has been a key element in determining comfort levels in transportation systems. In the automotive industry, researchers and engineers continuously work on reducing noise and vibration levels to minimize discomfort. Noise annoyance in vehicles results from structure-borne as well as air-borne noise from vehicle powertrain, tires and aeroacoustics. Whole-body vibration affects vehicle passenger comfort at the seat pan, back rest and feet. The objective of this research is to evaluate the comfort level of seated passengers in a vehicle from noise and whole-body vibration by considering both separate and combined modality. The noise and vibration data were recorded and analysed in two vehicles on the same highway road with four different speeds. The vibration exposure in vehicle were evaluated based on ISO2631-1:1997. Noise exposure was based on A-weighted sound pressure level. The combined discomfort on noise and vibration were quantifie...