An appropriate constitutive model embedded in a finite element engine is the key to the successfu... more An appropriate constitutive model embedded in a finite element engine is the key to the successful prediction of the observed behaviour of geotechnical structures. However, to capture the behaviour of geomaterials accurately, the constitutive models have to be complex involving a large number of material parameters and constants. This paper presents a methodology for converting or recasting complex constitutive models for geomaterials developed based on any constitutive theory into a fully trained Artificial Neural Network (ANN), which is then embedded in an appropriate finite element solution code. The length of strain trajectory traced by a material point, also called ‘intrinsic time’ is used as an additional input parameter in training. For the purpose of illustration, two constitutive models viz. Hardening Soil Model available in the commercial software, PLAXIS and a two-surface deviatoric hardening model in the multilaminate framework have been cast in the form of an ANN. Computational efficiency is perceived to be the main advantage of this methodology.
International Journal for Numerical and Analytical Methods in Geomechanics, 1998
Abstract A numerical model is proposed to analyse elastic as well as elastoplastic behaviour of s... more Abstract A numerical model is proposed to analyse elastic as well as elastoplastic behaviour of stone-column reinforced foundations. The stone-columns are assumed to be dispersed within the in situ soil and a homogenization technique is invoked to establish equivalent ...
An 'equivalent' material approach is presented for the computation of the elastic prope... more An 'equivalent' material approach is presented for the computation of the elastic properties of brick masonry. A stacked brick-mortar system consisting of a series of parallel layers which behave elastically is introduced. This is extended such that masonry with two sets of mortar joints ( ...
... Computers and Geotechnics 2 (1 986) 8999 SYIlIETRIC T ItEITIAL STIFFNESS FOIIIILATION FOR liO... more ... Computers and Geotechnics 2 (1 986) 8999 SYIlIETRIC T ItEITIAL STIFFNESS FOIIIILATION FOR liOIItSSIATE0 PLASTICI'rY GN PANDE Department of Civil ... A numerical scheme is proposed in which the response of a material with nonassociated flow rule is made equivalent to ...
As the temperature of a saturated porous medium drops, the water in the pores starts to freeze. S... more As the temperature of a saturated porous medium drops, the water in the pores starts to freeze. Since the temperature at which the phase change takes place is dependent on the pore size, the permeability of the medium changes continuously. Simultaneously, due to the expansion of water on freezing, it is forced to migrate through the pore body thus inducing stresses in material matrix. The stresses developed and the consequent frost damage are therefore dependent on the change in the permeability characteristics of the medium on freezing. This paper deals with the numerical prediction of permeability characteristics of porous cemented media saturated with water undergoing progressive freezing. A bond percolation model is used to generate the pore structure according to an assumed poresize distribution. Permeability of the medium at various temperatures is computed by solving the network problem. The computed results are compared with other analytical and experimental results. The proposed model predicts a threshold temperature below which permeability drops to zero. This phenomenon is crucial in developing a deeper understanding of the mechanism of frost damage to cemented porous materials such as bricks, stone, concrete, etc.
... ( denotes the shear modulus. ... a) LEHOST, a finite element analyzer [9]; (b) ANA LYZE [10],... more ... ( denotes the shear modulus. ... a) LEHOST, a finite element analyzer [9]; (b) ANA LYZE [10], a finiteelement stiffness code developed at the Wright Patterson Air Force Base; (c) the integrated force method (IFM) [ll]; (d) the simplified force method; and (e) a closedform IFM ...
An appropriate constitutive model embedded in a finite element engine is the key to the successfu... more An appropriate constitutive model embedded in a finite element engine is the key to the successful prediction of the observed behaviour of geotechnical structures. However, to capture the behaviour of geomaterials accurately, the constitutive models have to be complex involving a large number of material parameters and constants. This paper presents a methodology for converting or recasting complex constitutive models for geomaterials developed based on any constitutive theory into a fully trained Artificial Neural Network (ANN), which is then embedded in an appropriate finite element solution code. The length of strain trajectory traced by a material point, also called ‘intrinsic time’ is used as an additional input parameter in training. For the purpose of illustration, two constitutive models viz. Hardening Soil Model available in the commercial software, PLAXIS and a two-surface deviatoric hardening model in the multilaminate framework have been cast in the form of an ANN. Computational efficiency is perceived to be the main advantage of this methodology.
International Journal for Numerical and Analytical Methods in Geomechanics, 1998
Abstract A numerical model is proposed to analyse elastic as well as elastoplastic behaviour of s... more Abstract A numerical model is proposed to analyse elastic as well as elastoplastic behaviour of stone-column reinforced foundations. The stone-columns are assumed to be dispersed within the in situ soil and a homogenization technique is invoked to establish equivalent ...
An 'equivalent' material approach is presented for the computation of the elastic prope... more An 'equivalent' material approach is presented for the computation of the elastic properties of brick masonry. A stacked brick-mortar system consisting of a series of parallel layers which behave elastically is introduced. This is extended such that masonry with two sets of mortar joints ( ...
... Computers and Geotechnics 2 (1 986) 8999 SYIlIETRIC T ItEITIAL STIFFNESS FOIIIILATION FOR liO... more ... Computers and Geotechnics 2 (1 986) 8999 SYIlIETRIC T ItEITIAL STIFFNESS FOIIIILATION FOR liOIItSSIATE0 PLASTICI'rY GN PANDE Department of Civil ... A numerical scheme is proposed in which the response of a material with nonassociated flow rule is made equivalent to ...
As the temperature of a saturated porous medium drops, the water in the pores starts to freeze. S... more As the temperature of a saturated porous medium drops, the water in the pores starts to freeze. Since the temperature at which the phase change takes place is dependent on the pore size, the permeability of the medium changes continuously. Simultaneously, due to the expansion of water on freezing, it is forced to migrate through the pore body thus inducing stresses in material matrix. The stresses developed and the consequent frost damage are therefore dependent on the change in the permeability characteristics of the medium on freezing. This paper deals with the numerical prediction of permeability characteristics of porous cemented media saturated with water undergoing progressive freezing. A bond percolation model is used to generate the pore structure according to an assumed poresize distribution. Permeability of the medium at various temperatures is computed by solving the network problem. The computed results are compared with other analytical and experimental results. The proposed model predicts a threshold temperature below which permeability drops to zero. This phenomenon is crucial in developing a deeper understanding of the mechanism of frost damage to cemented porous materials such as bricks, stone, concrete, etc.
... ( denotes the shear modulus. ... a) LEHOST, a finite element analyzer [9]; (b) ANA LYZE [10],... more ... ( denotes the shear modulus. ... a) LEHOST, a finite element analyzer [9]; (b) ANA LYZE [10], a finiteelement stiffness code developed at the Wright Patterson Air Force Base; (c) the integrated force method (IFM) [ll]; (d) the simplified force method; and (e) a closedform IFM ...
Uploads