The EU Directive on machinery requires the emission of whole-body and hand-arm vibration from mobile machinery to be declared. One of the major problems in development of standards for verification of the declared values that has been experienced by the responsible CEN Technical Committee (TC231) is to define the test conditions, especially the surface over which the machines shall be travelling.
The objective of this project is to develop and evaluate test methods using artificial test tracks (smooth test tracks with obstacles).
Measurements of whole-body vibration have been made on three categories of industrial trucks (ware house trucks, large counterbalance trucks and all terrain vehicles) under actual work conditions so as to identify typical ranges of vibration values and to get targets for the adjustments of the characteristics of the test tracks. A draft method for the measurement of vibration on steering wheels has been elaborated and a programme of work is underway to show the possible effect of hand impedance and accelerometer mass on measurements of steering wheel vibration. The effectiveness of four suspension seats for reducing vertical vibration has been compared in the laboratory on a vibration simulator and on a counterbalance truck in accordance with recommendations from CEN draft standards. The results show that it is acceptable to measure the vibration at the seat base mounting on the truck and to multiply the value thus obtained by the laboratory seat transmissibility, measured by the procedure and at the vibration levels recommended in the applicable CEN draft standard, for assessing the vertical vibration transmitted to the truck driver. A tyre model is being elaborated to study the effect of new set of tyres on the truck vibration emission. A test bench is being built to determine tyre dynamic characteristics.
Funding SchemeCSC - Cost-sharing contracts
S3 7HQ Sheffield