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36. Stresses and displacements in nonlinear soil media
74
ABSTRACTS method was found to be a powerful tool for solving problems which involve either linear or nonlinear media. (Author's summary)
34.
E . T . H a n r a h a n . Analysing strain in real solids, Cir. Engng Publ. W o r k Rev., M a r c h (1968). Mention is made of some of the parameters commonly in use in connection with the theory of elasticity. They are shown to be unsuitable for application to the problem of real solid.s, chiefly because with such materials, the amount of both stress and strain caused by the tangential (i.e. shear) component of the stress system is totally independent of that resulting from the normal (i.e. compressive or tensile) component. A new simple formula is proposed for evaluating strain as the sum of two independent quantities, each being derived from the appropriate stress-strain relationship, viz. shear (G) and compression (K). (Author's summary)
35.
K. Hiieg, J. T. Christian and R. V. Whitman. Settlement of strip load on elastic-plastic soil, J. Soil Mech. Fndns. Div., ASCE, 94, SM2, Proc. Paper 5850, March, pp. 431-445 (1968). T h e gradual development of the yielded zone beneath a strip footing on an idealized elastic-plastic soil is analyzed. The corresponding stress and displacement fields and the accumulations of footing settlements after local shear failure has occurred is also shown. Factors affecting the magnitude of the displacements and the nature of the Ioadsettlemment curve are studied. The development of the electronic computer has made it possible to use finite numerical approximations to solve •roblems in soil mechanics that were hitherto insolvable by conventional analyses. (Author's Summary)
36.
Y . H . Huang. Stresses and displacements in nonlinear soil media. J. Soil Mech. Fndns. Div., ASCE, 94, SM1, Proc. Paper 5714, January, pp. 1-19 (1968). A method is presented for determining the vertical stresses and displacements in semiinfinite nonlinear soil media under circular loaded areas. The soil is assumed to be incompressible with an elastic modulus varying with the state of the stresses. The medium is arbitrarily divided into seven layers in which the stresses and displacements are determined by a high speed computer using Burmister's layered theory and the principle of successive approximations. The results of this stud,y reveal that the nonlinear behaviour of soils has a relatively small effect on stresses but a large effect on displacements. This may explain why Boussinesq's solution of stresses based on linear theory has been applied to soils with great success even though soils themselves are basically nonlinear. Because the differences in stresses between linear and nonlinear theory are not too significant, the displacements in a nonlinear medium can be estimated by a simplified method based on Boussinesq's stress distribution. It is found that this simplified method checks closely with .the method presented, especially at large radial distances. (Author's Summary)
37.
Igor L. Paul, Hariharan Sankaran and James J. Jackson. General vehicle dynamic model. Massachussetts Inst. of Tech., Cambridge. Engineering Projects Lab. Nov., 189 p. (1966). Two computer programs were developed to calculate the three-dimensional dynamics of a rigid high-speed~ ground-vehicle supported vertically and laterally by an arbitrary n u m b e r of suspensions and excited by arbitrary inputs (acting on the suspensions or on the vehicle body). The first program models each suspension by a linear spring and damper in parallel connected to the unsprung mass and another linear spring and damper in parallel joining the unsprung mass and the vehicle. This model is applicable to a limited class of suspensions over their linear operating range. The second, much more comprehensive program permits non-linear a n d / o r 'active' suspension elements. Each suspension can consist of masses connected (in series or parallel) by elements with force characteristics which can be any function of time or of the relative or absolute displacements, velocities or accelerations of any of the masses (including the vehicle mass). Both programs accept sinusoidal, step, ramp or arbitrary function inputs to the suspensions and print out any or all of the following vehicle response parameters as a function of time: vertical and lateral d,isplacement, velocity and acceleration of the vehicle center of mass; vehicle roll, pitch and yaw (and their first and second derivatives); suspension forces on the vehicle and on the guideway. (U.S. Gov. Res. Dev. Rep., 10.8.67, PB-173650)
38.
James C. Armstrong and Wayne A. Dunlap. The use of particulate mechanics in the simulation of stress-strain characteristics of granular materials. Texas Transportation Inst., College Station. Aug., 110 p. (1966).
ABSTRACTS method was found to be a powerful tool for solving problems which involve either linear or nonlinear media. (Author's summary)
34.
E . T . H a n r a h a n . Analysing strain in real solids, Cir. Engng Publ. W o r k Rev., M a r c h (1968). Mention is made of some of the parameters commonly in use in connection with the theory of elasticity. They are shown to be unsuitable for application to the problem of real solid.s, chiefly because with such materials, the amount of both stress and strain caused by the tangential (i.e. shear) component of the stress system is totally independent of that resulting from the normal (i.e. compressive or tensile) component. A new simple formula is proposed for evaluating strain as the sum of two independent quantities, each being derived from the appropriate stress-strain relationship, viz. shear (G) and compression (K). (Author's summary)
35.
K. Hiieg, J. T. Christian and R. V. Whitman. Settlement of strip load on elastic-plastic soil, J. Soil Mech. Fndns. Div., ASCE, 94, SM2, Proc. Paper 5850, March, pp. 431-445 (1968). T h e gradual development of the yielded zone beneath a strip footing on an idealized elastic-plastic soil is analyzed. The corresponding stress and displacement fields and the accumulations of footing settlements after local shear failure has occurred is also shown. Factors affecting the magnitude of the displacements and the nature of the Ioadsettlemment curve are studied. The development of the electronic computer has made it possible to use finite numerical approximations to solve •roblems in soil mechanics that were hitherto insolvable by conventional analyses. (Author's Summary)
36.
Y . H . Huang. Stresses and displacements in nonlinear soil media. J. Soil Mech. Fndns. Div., ASCE, 94, SM1, Proc. Paper 5714, January, pp. 1-19 (1968). A method is presented for determining the vertical stresses and displacements in semiinfinite nonlinear soil media under circular loaded areas. The soil is assumed to be incompressible with an elastic modulus varying with the state of the stresses. The medium is arbitrarily divided into seven layers in which the stresses and displacements are determined by a high speed computer using Burmister's layered theory and the principle of successive approximations. The results of this stud,y reveal that the nonlinear behaviour of soils has a relatively small effect on stresses but a large effect on displacements. This may explain why Boussinesq's solution of stresses based on linear theory has been applied to soils with great success even though soils themselves are basically nonlinear. Because the differences in stresses between linear and nonlinear theory are not too significant, the displacements in a nonlinear medium can be estimated by a simplified method based on Boussinesq's stress distribution. It is found that this simplified method checks closely with .the method presented, especially at large radial distances. (Author's Summary)
37.
Igor L. Paul, Hariharan Sankaran and James J. Jackson. General vehicle dynamic model. Massachussetts Inst. of Tech., Cambridge. Engineering Projects Lab. Nov., 189 p. (1966). Two computer programs were developed to calculate the three-dimensional dynamics of a rigid high-speed~ ground-vehicle supported vertically and laterally by an arbitrary n u m b e r of suspensions and excited by arbitrary inputs (acting on the suspensions or on the vehicle body). The first program models each suspension by a linear spring and damper in parallel connected to the unsprung mass and another linear spring and damper in parallel joining the unsprung mass and the vehicle. This model is applicable to a limited class of suspensions over their linear operating range. The second, much more comprehensive program permits non-linear a n d / o r 'active' suspension elements. Each suspension can consist of masses connected (in series or parallel) by elements with force characteristics which can be any function of time or of the relative or absolute displacements, velocities or accelerations of any of the masses (including the vehicle mass). Both programs accept sinusoidal, step, ramp or arbitrary function inputs to the suspensions and print out any or all of the following vehicle response parameters as a function of time: vertical and lateral d,isplacement, velocity and acceleration of the vehicle center of mass; vehicle roll, pitch and yaw (and their first and second derivatives); suspension forces on the vehicle and on the guideway. (U.S. Gov. Res. Dev. Rep., 10.8.67, PB-173650)
38.
James C. Armstrong and Wayne A. Dunlap. The use of particulate mechanics in the simulation of stress-strain characteristics of granular materials. Texas Transportation Inst., College Station. Aug., 110 p. (1966).