A new optical method for soil stress and strain investigation

Effects of reduced inflation pressure and vehicle loading on off-road traction and soil stress and deformation state

“…One significant feature of the transducers is that they are integrated with micro-instrumentation amplifiers, so that output signals are ready for calculations (no external bridge conditioners/amplifiers between the transducer and computer are needed). For more details please refer to [10]. Measured soil pressure data were collected on the hard disk of an industrial computer, which was powered from a portable gas generator.…”

“…The probes can be displaced in two directions: vertical and horizontal. Several designs of the probes were tested [9,10]. First, flat aluminium lists, 3 · 20 mm in cross-section were used, but they were highly deformable.…”

Determining and analysing the stress state under wheeled-vehicle loads

“…It is well known and documented in the literature that tyres at decreased inflation pressure perform significantly better in off-road conditions [10,11,18]. Results from the literature prove that soil stresses decrease at lower inflation pressures [20,21], but this effect was observed for very low inflation pressures (approximately 40-50 kPa). Such a low pressure is possible for large tractor tyres, according to tyre manufacturers' recommendations.…”

“…1): the principal stresses S 1 , S 2 , and S 3 , the octahedral stresses mean normal stress (MNS), and the octahedral shear stress (OCTSS). The method has been described in references [17] to [20]. The SSTs used were 35 mm in diameter and the pressure transducers were 20 mm in diameter.…”

Sandur, sandr

“…The typical SST consists of six pressure transducers positioned to obtain soil pressure values needed for calculation of S1, S2, S3 and MNS, OCTSS. Several SST designs are in use (Bailey et al, 1987;Horn et al, 1992;Pytka , 2002). The SST can also be connected to soil deformation transducers (Horn et al, 1994;Pytka et al, 2002), thus enabling the determination of soil stress and deformation state in simultaneous measurements.…”