Assessing Friction Laws for Simulating Bowed-String Motion

In order to carry out meaningful "virtual" experiments on the playability of bowed-string instruments, a simulation model is required that can reproduce all details relevant to a musician. Measured transient behaviour of machine-bowed strings is compared in detail with predictions from a range of previously-published computer simulation models. The general trends of waveforms and parameter dependence observed experimentally are successfully predicted, but some important details are not well captured by any of the models tested. The discrepancies, mainly associated with uncertainty about the correct model for the frictional interaction between bow and string, are examined systematically to reveal patterns of sensitivity to specific features of the models and to provide guidance on aspects of those models that may require enhancement to achieve a closer match to experiment. Of the models tested, the friction model based on contact temperature performed significantly better than more traditional ones based on instantaneous sliding speed.