Jaroslaw Pytka

Determination of the stress-strain relationship for sandy soil in field experiments

Abstract A new method for determination of soil stress-strain relationships under traffic in field experiments is described. Tire or track sinkage as well as vertical movements of a point in soil volume can be quantified using an optoelectronic method. In soil stress measurements, a standard stress state transducer (SST) with six strain gage type pressure transducers was used. Detailed descriptions of technical solutions are described and presented on illustrations. The measuring system is capable of collecting simultaneously soil stress and deformation data. Results from a preliminary experiment with the use of a tracked armoured vehicle are presented and analysed. Soil stress and deformation data measured simultaneously are used for the evaluation of soil stress–strain relationship, which may become a mechanical characteristic of the investigated soil.

A portable wheel tester for tyre-road friction and rolling resistance determination

The paper describes theory of operation, design and construction as well as results from primarily experiments with a portable wheel tester that has been developed by the authors as a device for on-site determination of tyre-road braking/driving friction and rolling resistance. The paper includes schematics, drawings, descriptions as well as graphical results form early tests with the presented device. It is expected that the tester can be useful in road accident reconstruction applications as well as in vehicle dynamics research.