- Email: [email protected]
Relationship between stress and deformation of frozen soils taking into account the time factor
118 102.
ABSTRACTS H. H. Van Der Watt. Influence of particle size distribution on soil compactibility. Agrochemo-
physiea 1, 79-86 (1969). [E.afr.f.] [Univ. Pretoria, S. Africa]. Only the coarse sand (1-2 ram) and silt -+ clay (--_'0.002 ram) fractions were required for obtaining a highly significant regression equation for maximum bulk density attainable under specified experimental conditions; limitations of such an equation are discussed and a diagram for evaluating soil compactibility from rate of particle-size analysis is presented. (Soils and
Fertilizers.) 103.
B. D. Van Deusen (Chrysler Corp.). Truck suspension system optimization. S.A.E. Paper No. 710222, Automot. Engng. Congr., January 11-15 (1971). Investigations were undertaken to improve the suspension of a large military tractor having a spring-and-link suspension. Testing involved operation of the suitably instrumented vehicle over four proving-ground courses varying in roughness. Vibrational level at various points within the vehicle and the effects of suspension modifications were determined. Two computer models were also developed to study suspension parameters. Test and model results have been applied in the design of a new vehicle. Lower tyre-spring rates, increased jounce travel, reduced suspension-spring rates, provision of shock-absorbers and new springs with reduced interleaf friction have substantially improved ride. (M.LR.A.)
104.
S. S. Vyalov. Relationship between stress and deformation of frozen soils taking into account the time factor. 9 pp. (1970). In order to study the relationship between stress and deformation of frozen soils, experiments were made on displacement along wooden rods which were frozen into the ground, on the penetration into frozen soils of hard indenters, and on tension and compression. The experiments were conducted with various types of soils (from clays to light-weight sandy silts), at various sub-zero temperatures, which were always constant for any given experiment. In order to show the effect of time, experim~.nts conducted were both short-term and very lengthy (lasting several months and even more than a year). (U.S. Gov. Res. Dev. Rep., 25.3.71, AD-717 304.)
105.
N. A. Vzyatishev. Selection of the parameters of spherical and arc-type couplings for tractor vehicles designed for semi-trailers. Avtom. Prom. No. 5, pp. 16-19 (May 1971). The article deals with selection of the parameters of spherical and arc-type semi-trailer couplings affecting stability. Features of the kinematics of these couplings and their influence on semi-trailer lateral stability are shown in the figure. With a spherical or arc-type semi-trailer coupling, as at (b) in the figure, semi-trailer roll brought about by sideways slope of the road surface leads to an increase in the positive level of potential energy for the forward part of the semi-trailer and the emergence of a restoring moment. However, if a conventional semi-trailer coupling (a) is used, the lateral-stability characteristics deteriorate in the presence of roll, the level of potential energy declining and an overturning moment appearing. The major design parameter of spherical and arc-type semi-trailer couplings, on which depend the semi-trailer lateral-stability characteristics, is the radius of the sphere or arc. This must be selected for the effect of both static and dynamic forces. Hence, the characteristic features of a tractor/trailercombination oscillatory system with use of a spherical or arc-type semi-trailer coupling are examined. Graphs show the relationships, with and without a coupling flexible link, for the arc or sphere radius and (a) tractor/trailer-combination-oscillatory-system characteristics and (b) tractor/trailer-combination static and dynamic lateral stability. With increase of the coupling arc or sphere radius, the radius of roll changes linearly; the moment-of-inertia curve has a minimum value which is dependent on the change in the sphere or arc radius. Under certain conditions, an arc-type or spherical semi-trailer coupling improves the dynamic-stability characteristics with a steady-state resonance by a factor of 1.6 compared with the conventional variety. The presence of a flexible link in the coupling, or a change in the resistance coefficient of the trailer suspension and coupling, leads to a reduction of the absolute stability-coefficient values. Radii of 75-150 cm are indicated for the coupling arc or sphere. Computer calculations revealed that the nature of the change in dynamic stability as a function of coupling arc or sphere radius is the same under transient as under steady-state operating conditions. However, excessive increase of the arc or sphere radius gives rise to a considerable moment about the vertical axis with yawing of the sprung mass, particularly on short-wheelbase semi-trailers. Experimental and computer-derived curves of dynamic-stability coefficient vs. coupling arc or sphere radius show good correlation. (M.LR.A.)
ABSTRACTS H. H. Van Der Watt. Influence of particle size distribution on soil compactibility. Agrochemo-
physiea 1, 79-86 (1969). [E.afr.f.] [Univ. Pretoria, S. Africa]. Only the coarse sand (1-2 ram) and silt -+ clay (--_'0.002 ram) fractions were required for obtaining a highly significant regression equation for maximum bulk density attainable under specified experimental conditions; limitations of such an equation are discussed and a diagram for evaluating soil compactibility from rate of particle-size analysis is presented. (Soils and
Fertilizers.) 103.
B. D. Van Deusen (Chrysler Corp.). Truck suspension system optimization. S.A.E. Paper No. 710222, Automot. Engng. Congr., January 11-15 (1971). Investigations were undertaken to improve the suspension of a large military tractor having a spring-and-link suspension. Testing involved operation of the suitably instrumented vehicle over four proving-ground courses varying in roughness. Vibrational level at various points within the vehicle and the effects of suspension modifications were determined. Two computer models were also developed to study suspension parameters. Test and model results have been applied in the design of a new vehicle. Lower tyre-spring rates, increased jounce travel, reduced suspension-spring rates, provision of shock-absorbers and new springs with reduced interleaf friction have substantially improved ride. (M.LR.A.)
104.
S. S. Vyalov. Relationship between stress and deformation of frozen soils taking into account the time factor. 9 pp. (1970). In order to study the relationship between stress and deformation of frozen soils, experiments were made on displacement along wooden rods which were frozen into the ground, on the penetration into frozen soils of hard indenters, and on tension and compression. The experiments were conducted with various types of soils (from clays to light-weight sandy silts), at various sub-zero temperatures, which were always constant for any given experiment. In order to show the effect of time, experim~.nts conducted were both short-term and very lengthy (lasting several months and even more than a year). (U.S. Gov. Res. Dev. Rep., 25.3.71, AD-717 304.)
105.
N. A. Vzyatishev. Selection of the parameters of spherical and arc-type couplings for tractor vehicles designed for semi-trailers. Avtom. Prom. No. 5, pp. 16-19 (May 1971). The article deals with selection of the parameters of spherical and arc-type semi-trailer couplings affecting stability. Features of the kinematics of these couplings and their influence on semi-trailer lateral stability are shown in the figure. With a spherical or arc-type semi-trailer coupling, as at (b) in the figure, semi-trailer roll brought about by sideways slope of the road surface leads to an increase in the positive level of potential energy for the forward part of the semi-trailer and the emergence of a restoring moment. However, if a conventional semi-trailer coupling (a) is used, the lateral-stability characteristics deteriorate in the presence of roll, the level of potential energy declining and an overturning moment appearing. The major design parameter of spherical and arc-type semi-trailer couplings, on which depend the semi-trailer lateral-stability characteristics, is the radius of the sphere or arc. This must be selected for the effect of both static and dynamic forces. Hence, the characteristic features of a tractor/trailercombination oscillatory system with use of a spherical or arc-type semi-trailer coupling are examined. Graphs show the relationships, with and without a coupling flexible link, for the arc or sphere radius and (a) tractor/trailer-combination-oscillatory-system characteristics and (b) tractor/trailer-combination static and dynamic lateral stability. With increase of the coupling arc or sphere radius, the radius of roll changes linearly; the moment-of-inertia curve has a minimum value which is dependent on the change in the sphere or arc radius. Under certain conditions, an arc-type or spherical semi-trailer coupling improves the dynamic-stability characteristics with a steady-state resonance by a factor of 1.6 compared with the conventional variety. The presence of a flexible link in the coupling, or a change in the resistance coefficient of the trailer suspension and coupling, leads to a reduction of the absolute stability-coefficient values. Radii of 75-150 cm are indicated for the coupling arc or sphere. Computer calculations revealed that the nature of the change in dynamic stability as a function of coupling arc or sphere radius is the same under transient as under steady-state operating conditions. However, excessive increase of the arc or sphere radius gives rise to a considerable moment about the vertical axis with yawing of the sprung mass, particularly on short-wheelbase semi-trailers. Experimental and computer-derived curves of dynamic-stability coefficient vs. coupling arc or sphere radius show good correlation. (M.LR.A.)