South African industry in general lacks knowledge and awareness about the adverse health effects of vibration on its workers, so says Prof Wikus van Niekerk, head of the Department of Mechanical Engineering at the University of Stellenbosch. Cause for concern indeed, as he quotes statistics that SA workers are exposed to vibration levels of up to 5-10 times higher than that which workers in First World countries like the UK and the USA are allowed to be exposed.
Why is vibration an issue?
Vibration has two well-documented and defined effects on humans; firstly one of discomfort - an issue of annoyance, and secondly the adverse health aspects. There are well-documented cases of vibration affecting biodynamics, and varying psychological, physiological and pathological effects. Hand arm vibration syndrome (HAVS) is a compensable occupational disease according to the Occupational Health and Safety Act.
Spescom MeasureGraph recently supplied the electronic and hydraulic components from MTS which forms the basis for the newly commissioned R800 000 dynamic seat test facility, located within the Mechanical Engineering Laboratories at Stellenbosch University. With contributions from THRIP as well as funding by Ford Motor Company, the facility can boast that is one of only a few 'man-rated' facilities, worldwide.
The term 'man-rated' by definition means that humans are used in the actual testing process. A very real difference to using the 'dead-weight' alternative. It is expected that research into seating dynamics and seat transmissibility at this facility will continue for the next 4-5 years.
"The role that mechanical engineers play is vastly underestimated by government, the public and industry in general," says van Niekerk. "I am, however, confident that the research that we are about to embark upon at the facility, will go some way to highlighting the value of the work that we, the industry in general and the research community in particular, are doing at the facility."
Spescom MeasureGraph supplied Prof van Niekerk with the MTS Model 407 Controller and MTS hydraulic actuator. The 407 controller is a digitally supervised PIDF servo controller that provides complete control of the hydraulic actuator. The 407 includes AC and DC transducer conditioning, function generation (with the capability to accept externally generated command signals), servo valve drive signal generation, and hydraulic pressure control. Multiple Model 407 Controllers can be interconnected to accommodate multiple-channel testing.
The MTS 407 Controller is a standalone unit with its functions accessed via the front panel. Plug-in modules and electrical connections are easily accessible enabling the user to quickly connect and configure the controller to match the test requirements. With optional PC communications plug-in module and software, the controller can be operated remotely from a personal computer, a library of applications is available and the user can also program his own application in LabView.
For more information contact Trevor Leong, Spescom MeasureGraph, 011 266 1664, [email protected], www.spescom.com
Prof Wikus van Niekerk, a registered Professional Engineer, currently holds the post professor and chair in the Department of Mechanical Engineering at Stellenbosch University. He may be reached on 021 808 4251, [email protected]
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