Mechanical vibration and shock. Mechanical impedance of the human hand-arm system at the driving point

2015 ◽  
Keyword(s):  
Mechanical Vibration ◽  
Mechanical Impedance ◽  
Human Hand

scholarly journals An Experimental Study of the Influence of Hand-Arm Posture and Grip Force on the Mechanical Impedance of Hand-Arm System

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Wenjie Zhang ◽  
Qichao Wang ◽  
Zheng Xu ◽  
Hongmei Xu ◽  
Hang Li ◽  
...  
Keyword(s):  
Grip Force ◽  
Mechanical Impedance ◽  
Test System ◽  
Human Hand ◽  
Adult Males ◽  
Obvious Effect ◽  
Elbow Angle ◽  
Vibration Intensity ◽  
Vibration Excitation ◽  
40 Hz

In order to investigate the effects of hand-arm posture, grip force, push force, and vibration excitation intensity on the mechanical impedance of human hand-arm system, a test system with a self-developed vibration handle has been prepared. Based on the testing system, the mechanical impedance of the hand-arm system of seven Chinese adult males were tested and calculated under the random vibration excitation with the frequency of 10–1000 Hz. The results reveal that when the frequency is lower (<40 Hz), the hand-arm system with an elbow angle of 180o produces a higher mechanical impedance; when the frequency ranges from 40 Hz to 100 Hz, the hand-arm system with an elbow angle of 90o generates a higher mechanical impedance; while when the frequency is higher (>100 Hz), the hand-arm posture seems to have no obvious effect on the mechanical impedance. Higher grip or push force would increase the frequency corresponding to the peak value of the mechanical impedance and often correspond to a higher mechanical impedance in a specific frequency range (30–200 Hz). When the frequency is lower (<140 Hz), vibration intensity has certain effects on the mechanical impedance of the hand-arm system. In conclusion, vibration intensity does not directly affect the mechanical impedance, but an increase in grip or push force often causes an increase in mechanical impedance and a higher frequency that corresponds to the peak of mechanical impedance.

scholarly journals Stress and strain distributions in the human hand-arm system using finite element analysis

2017 ◽  
Vol 6 (2) ◽  
pp. 21
Author(s):  
Surajudeen Adewusi ◽  
Marc Thomas
Keyword(s):  
Finite Element ◽  
Mechanical Vibration ◽  
International Standard Organization ◽  
Human Hand ◽  
Stress And Strain ◽  
Stress Strain ◽  
Element Analysis ◽  
Standard Organization ◽  
Measurement And Evaluation ◽  
Frequency Weightings

This study presents stress and strain distributions in the human hand-arm system exposed to vibrations using finite element (FE) models. Frequency weightings at shoulder, elbow, wrist and palm based on stress and strain distributions were proposed. The stress/strain-based frequency weightings around the shoulder and elbow are comparable with that reported in the International Organization for Standardization ISO 5349-1, Mechanical vibration and shock– Measurement and evaluation of human exposure to mechanical vibration – part 1: General requirements, 2001. However, stress/strain-based frequency weightings around the palm and wrist are different above 20 Hz from the weighting reported by the International Standard Organization.  This study suggests the need for different frequency weightings for the assessment of the potential injury of different components of the hand-arm vibration syndrome.

“The Electro-Mechanical Analogy in Oscillation Theory”

1943 ◽  
Vol 47 (385) ◽  
pp. 22-26 ◽  
Author(s):  
R. G. Manley
Keyword(s):  
Dynamic Stiffness ◽  
Mechanical Vibration ◽  
Electric Circuit ◽  
Mechanical Impedance ◽  
Oscillation Theory ◽  
Full Description ◽  
Torsional Motion ◽  
Rational Basis ◽  
Equivalent Electric Circuit ◽  
Electric Circuits

It has long been realised that there is a precise analogy between the properties of vibrating mechanical systems and those of alternating current electric circuits. It was from this analogy that the concept of “ mechanical impedance ” (more appropriately termed “ dynamic stiffness ”) was derived, thus enabling the theory of certain types of mechanical vibration, notably torsional motion, to be put on a more rational basis.By means of analogous elements it is possible to represent a mechanical vibrating system, provided it includes no bending elements, by an equivalent electric circuit. The author has been unable to discover any full description of the process, and the object of the present paper is to set out the principles underlying the procedure and to illustrate them briefly by examples.

Distribution of mechanical impedance at the fingers and the palm of the human hand

2005 ◽  
Vol 38 (5) ◽  
pp. 1165-1175 ◽  
Author(s):  
R.G. Dong ◽  
J.Z. Wu ◽  
T.W. McDowell ◽  
D.E. Welcome ◽  
A.W. Schopper
Keyword(s):  
Mechanical Impedance ◽  
Human Hand

Vibrational Analysis of the Human Hand

1976 ◽  
Vol 20 (14) ◽  
pp. 267-271
Author(s):  
C.W. Suggs ◽  
John Wayne Mishoe
Keyword(s):  
Vibrational Analysis ◽  
Mechanical Impedance ◽  
Objective Evaluation ◽  
Human Hand ◽  
Apparent Mass ◽  
Mass System

Investigation of hand-arm vibration by means of mechanical impedance techniques has provided objective evaluation of the observation that most of the higher frequency vibration inputs at the hand are not transmitted into the arm. This is reflected in the impedance curves which show two orders of magnitude decrease in apparent mass as frequency is increased from 50 Hz to 1000 Hz. The system may be modeled as damped spring-mass system containing three masses interconnected by springs and dampers.

Measurement of Human Hand Impedance in Dual Arm Configurations

2004 ◽  
Vol 16 (6) ◽  
pp. 635-642 ◽  
Author(s):  
Yusaku Takeda ◽  
◽  
Yoshiyuki Tanaka ◽  
Toshio Tsuji
Keyword(s):  
Dynamic Characteristics ◽  
Arm Movements ◽  
Mechanical Impedance ◽  
Human Hand ◽  
Human Movements ◽  
Robot Cooperation ◽  
Dual Arm

Dynamic characteristics of a human extremity are usually expressed using the mechanical impedance. This paper examines hand impedance in dual arm movements while posture was maintained in dual-arm configurations. The results of experiments show that the orientation of viscosity ellipses roughly agrees with the human sagittal axis, tending to be oriented similar to stiffness ellipses. Viscosity and stiffness amplitude and orientation exceed those of single arm. Our results will be used in human-robot cooperation systems and in analyzing human movements.

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