Finite element analysis
regarding the propagationof transient vibrations fromhandheld equipment
The sample measured is a replica of the skin on a fingertip. In this case, thedifficulty of holding one’s finger absolutely still during the measurement
necessitates using the indirect method of measuring on replicas. The
objective was to obtain information for simulation of microgeometry of skin
to be able to create a simplified virtual model. The model was going to be
used in finite element analysis (FEA) regarding the propagation of transient
vibrations from handheld equipment, such as impact wrenches and chiselmachines, through the skin to the nerves where damage occurs. These
vibrations can cause a medical condition called “white fingers” which is acommon work-related health problem.
Before this government-sponsored project, the microgeometry of skin had
not yet been characterized for this specific purpose. This project’s main
objective was getting detailed information regarding skin’s microgeometry
over a large enough area to be able to draw general conclusions for use infurther investigations.

CASE STUDY FINITE ELEMENT ANALYSIS REGARDING THE PROPAGATION OF TRANSIENT VIBRATIONSFROM HANDHELD EQUIPMENT

Swerea IVF is a research institutethat offers advanced research andconsulting services to put newtechnology and new methods
into practice with a focus on
product, process and production
development. Swerea IVF alsooffers in-depth expertise in relation
to materials’ properties andapplications for ceramic, polymer
and textile materials. Swerea IVF ispart of the Swerea group, a Swedish
research group for industrial renewal
and sustainable development. They
produce, develop, and disseminate
research results in the areas ofmaterials development, production
developmentandproductdevelopment. Project current being
undertaken by Johan Berglund andHans Lindell.

1

■■ Measurements
Overview of skin with the measurement area depicted inside the rectangularblue grid.

2CASE STUDY FINITE ELEMENT ANALYSIS REGARDING THE PROPAGATION OF TRANSIENT VIBRATIONSFROM HANDHELD EQUIPMENT

5x9 mm Extended measurement.
Example of an evaluation of the sample’s geometry using SensoMAP
advanced contour module.

■■ Conclusions
Using the confocal technique, the 20X brightfield objective lens, andextended measurements, we were able to measure the skin geometry with ahigh enough resolution and sufficient reliability to draw general conclusions
regarding the size, height, and distribution of the ridges and lines of theskin. With this data, we were able to make a simplified model of the skin forsuccessful use in FEA.
For more information, check the Attenuation of hand-held machine
vibrations. Application of non-linear tuned vibration absorber.

CASE STUDY FINITE ELEMENT ANALYSIS REGARDING THE PROPAGATION OF TRANSIENT VIBRATIONSFROM HANDHELD EQUIPMENT3

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