Strand7 Webnotes - ST7-1.20 Nonlinear

ST7-1.20 Nonlinear
ST7-1.20.10 Nonlinear / Statics
1.2 MB	ST7-1.20.10.8 Troubleshooting Nonlinear Static Models Solutions to nonlinear FEA problems are approximate due to the iterative nature of the algorithms used to solve the problems. Before proceeding, review ST7-1.10.10.3 General Model Troubleshooting to ensure that the model is basically sound. In this example, a fictitious welded assembly, which is between two confining walls, is forced downwards by an eccentric load until lateral buckling occurs and contact is formed between the buckled member and the adjacent walls. The base of the buckling...
ST7-1.20.40 Nonlinear / Material
0.7 MB	ST7-1.20.40.6 Setting Up a Soil Analysis Strand7 is capable of performing common geotechnical analysis with five soil model types. Due to the nonlinear stress-strain response of the soil, the analysis generally utilises a Strand7 solver that is capable of performing Material Nonlinearity analysis (e.g. Nonlinear Static). The types of analysis that can be handled by Strand7 soil elements include Earth pressure , Short-term consolidation, Lateral earth pressure, Construction sequences .
0.7 MB	ST7-1.20.40.8 Strand7 Soil Models Strand7 offers five different soil material models for 2D plane strain, axisymmetric and 3D analysis: Linear Elastic Soil Mohr-Coulomb Soil Drucker-Prager Soil Duncan-Chang Soil Modified Cam-Clay Soil All of the soil models consider the effects of fluid content (e.g. water), void ratio, and in-situ stress. Soil models require a range of parameters to characterise their behaviour; this is illustrated in the following sections. The Linear Elastic Soil model is an isotropic soil material...
0.7 MB	ST7-1.20.40.9 Fluid Level in Soil Models Soil in a natural state contains voids between grains that are filled by air and fluid such as water. The fluid can greatly affect the in-situ stress state of the soil by adding mass and pressure to the soil strata. Trapped fluid in soil can also influence the stress in the soil skeleton under external loads by sharing a portion of the loads with the soil skeleton. Depending on the fluid content, the soil can be approximated with one of two limit situations: saturated or unsaturated. ...
0.7 MB	ST7-1.20.40.10 Modelling Nonlinear Concrete with Nonlinear Elastic Material This Webnote outlines the application of the Max Stress yield criterion for modelling nonlinear elastic concrete material. This modelling approach allows us to consider the concrete's different behaviour in compression and tension.
0.8 MB	ST7-1.20.40.12 CEB-FIP MC 90 Concrete Creep and Shrinkage The basic creep and shrinkage formulation in the CEB-FIP Model Code 90 utilises the hyperbolic law. This formulation can be directly entered into Strand7 using the Concrete Creep and Shrinkage Hyperbolic Law creep option. This document illustrates the process of extracting the required factors from the CEB-FIP Model Code 90 for concrete creep and shrinkage and entering them into Strand7. In this section the calculation procedure for the concrete material parameters is examined. where ...
0.8 MB	ST7-1.20.40.13 ACI-209 Concrete Creep and Shrinkage The basic creep and shrinkage formulation in ACI-209 utilises the hyperbolic law. This formulation can be entered directly into Strand7 using the Concrete Creep and Shrinkage Hyperbolic Law creep option. This Webnote illustrates the process of extracting the required factors from ACI-209 for concrete creep and shrinkage and entering them into Strand7. In this section the calculation procedure for the concrete material parameters is examined. The second material parameter considered is the...
0.9 MB	ST7-1.20.40.14 AS 3600-2009 Concrete Creep and Shrinkage This Webnote illustrates the process of extracting the required factors from AS3600-2009 for concrete creep and shrinkage effects and entering them into Strand7. The basic creep formulation in AS3600-2009 utilises the hyperbolic law. In this section the calculation procedure of concrete material parameters is examined. The next material parameter considered is the density of the concrete, . The third material parameter considered is the elastic modulus of the concrete at any time, Ecj. = 1.5 0.043 ...
0.8 MB	ST7-1.20.40.15 AASHTO Concrete Creep and Shrinkage This Webnote illustrates the process of extracting the required factors from the AASHTO LRFD Design Specifications (AASHTO LRFD) for concrete creep and shrinkage and entering them into Strand7. The basic creep and shrinkage formulation in AASHTO LRFD Bridge Design Specifications utilises the hyperbolic law with time-dependent factors. This formulation can be directly entered into Strand7 using the Concrete Creep and Shrinkage User Defined option. Article 5.4.2.3.1 of AASHTO LRFD Bridge...
1.1 MB	ST7-1.20.40.16 Basic Material Nonlinear Analysis This Webnote gives a brief summary of material nonlinear analysis and showcases a simple example. To start a material nonlinear analysis, a stress-strain curve is usually required. A typical stress-strain curve for low and medium carbon steels is shown below, with part of the curve exaggerated for clarity. For stresses up to the proportional limit, stress will be linearly proportional to the strain according to figure 1. If the stress exceeds the proportional limit then material nonlinear...
1.0 MB	ST7-1.20.40.17 Material Nonlinearity and Yield Criteria Strand7 supports various linear, nonlinear and specialised material models suitable for modelling a range of different physical materials such as ductile metals, brittle concrete and soils. ...
ST7-1.20.50 Nonlinear / Geometry
1.0 MB	ST7-1.20.50.2 Nonlinear vs Linear Buckling Analysis This Webnote examines the critical buckling load for four typical column configurations. Results from linear buckling analyses are compared with hand calculations using the familiar Euler equation in conjunction with effective length constants, which may be obtained from any text on elastic stability. Results from linear buckling analysis are then compared with those from a nonlinear buckling analysis. ...
0.4 MB	ST7-1.20.50.3 Modelling a Snap-Through Buckle Buckling and post-buckling prediction is one useful applications of finite element analysis. A nonlinear buckling analysis can give a good indication of the structural response near the onset of buckling, and post-buckling if the solution can be made sufficiently stable. Snap-through buckling is one situation that exhibits stable post-buckling behaviour. This Webnote examines the prediction of snap-through buckling using Strand7. ST7-1.20.10.1 Nonlinear Elastic and Inelastic Buckling of a...
ST7-1.20.60 Nonlinear / Construction Sequence
1.5 MB	ST7-1.20.60.1 Construction Sequence Analysis Strand7 allows the modelling of construction sequence scenarios with sophisticated construction sequence tools. These tools have been designed to allow the user to easily model a staged construction such as a multi-storey building, a cable stay bridge, a staged excavation, a tunnel, an in-ground water tank, etc. For many structures it is important to understand how the structure will behave during its construction. The entire construction, excavation or deconstruction process can be simulated...
0.9 MB	ST7-1.20.60.2 Soil In-Situ Stress in Construction Sequence Analysis Construction sequence analysis involving soil requires the consideration of the soil in-situ stress state in each of the defined analysis stages. When adding soil in a subsequent stage of a staged analysis (i.e. soil that is not present in the initial stage), the in-situ stress distribution of the added soil needs to be pre-computed. One minor consideration that may affect the results interpretation when adding soil is that existing soil can displace during the construction stage, before the new...
0.6 MB	ST7-1.20.60.3 Applying Pre Strain Attributes in Construction Sequence Analysis This Webnote explores the handling of the element pre strain attribute in construction sequence (staged) analysis. In a staged analysis, the dimensions of an element at the beginning of a stage may be different to the as modelled mesh dimensions. The "initial" dimension depends on the Morph setting in the element's birth stage and the morphed element dimensions, which in turn affect the amount of contraction or expansion resulting from a pre strain attribute.

1.2 MB

ST7-1.20.10.8 Troubleshooting Nonlinear Static Models
Solutions to nonlinear FEA problems are approximate due to the iterative nature of the algorithms used to solve the problems. Before proceeding, review ST7-1.10.10.3 General Model Troubleshooting to ensure that the model is basically sound. In this example, a fictitious welded assembly, which is between two confining walls, is forced downwards by an eccentric load until lateral buckling occurs and contact is formed between the buckled member and the adjacent walls. The base of the buckling...

0.7 MB

ST7-1.20.40.6 Setting Up a Soil Analysis
Strand7 is capable of performing common geotechnical analysis with five soil model types. Due to the nonlinear stress-strain response of the soil, the analysis generally utilises a Strand7 solver that is capable of performing Material Nonlinearity analysis (e.g. Nonlinear Static). The types of analysis that can be handled by Strand7 soil elements include Earth pressure , Short-term consolidation, Lateral earth pressure, Construction sequences .

0.7 MB

ST7-1.20.40.8 Strand7 Soil Models
Strand7 offers five different soil material models for 2D plane strain, axisymmetric and 3D analysis: Linear Elastic Soil Mohr-Coulomb Soil Drucker-Prager Soil Duncan-Chang Soil Modified Cam-Clay Soil All of the soil models consider the effects of fluid content (e.g. water), void ratio, and in-situ stress. Soil models require a range of parameters to characterise their behaviour; this is illustrated in the following sections. The Linear Elastic Soil model is an isotropic soil material...

0.7 MB

ST7-1.20.40.9 Fluid Level in Soil Models
Soil in a natural state contains voids between grains that are filled by air and fluid such as water. The fluid can greatly affect the in-situ stress state of the soil by adding mass and pressure to the soil strata. Trapped fluid in soil can also influence the stress in the soil skeleton under external loads by sharing a portion of the loads with the soil skeleton. Depending on the fluid content, the soil can be approximated with one of two limit situations: saturated or unsaturated. ...

0.7 MB

ST7-1.20.40.10 Modelling Nonlinear Concrete with Nonlinear Elastic Material
This Webnote outlines the application of the Max Stress yield criterion for modelling nonlinear elastic concrete material. This modelling approach allows us to consider the concrete's different behaviour in compression and tension.

0.8 MB

ST7-1.20.40.12 CEB-FIP MC 90 Concrete Creep and Shrinkage
The basic creep and shrinkage formulation in the CEB-FIP Model Code 90 utilises the hyperbolic law. This formulation can be directly entered into Strand7 using the Concrete Creep and Shrinkage Hyperbolic Law creep option. This document illustrates the process of extracting the required factors from the CEB-FIP Model Code 90 for concrete creep and shrinkage and entering them into Strand7. In this section the calculation procedure for the concrete material parameters is examined. where ...

0.8 MB

ST7-1.20.40.13 ACI-209 Concrete Creep and Shrinkage
The basic creep and shrinkage formulation in ACI-209 utilises the hyperbolic law. This formulation can be entered directly into Strand7 using the Concrete Creep and Shrinkage Hyperbolic Law creep option. This Webnote illustrates the process of extracting the required factors from ACI-209 for concrete creep and shrinkage and entering them into Strand7. In this section the calculation procedure for the concrete material parameters is examined. The second material parameter considered is the...

0.9 MB

ST7-1.20.40.14 AS 3600-2009 Concrete Creep and Shrinkage
This Webnote illustrates the process of extracting the required factors from AS3600-2009 for concrete creep and shrinkage effects and entering them into Strand7. The basic creep formulation in AS3600-2009 utilises the hyperbolic law. In this section the calculation procedure of concrete material parameters is examined. The next material parameter considered is the density of the concrete, . The third material parameter considered is the elastic modulus of the concrete at any time, Ecj. = 1.5 0.043 ...

0.8 MB

ST7-1.20.40.15 AASHTO Concrete Creep and Shrinkage
This Webnote illustrates the process of extracting the required factors from the AASHTO LRFD Design Specifications (AASHTO LRFD) for concrete creep and shrinkage and entering them into Strand7. The basic creep and shrinkage formulation in AASHTO LRFD Bridge Design Specifications utilises the hyperbolic law with time-dependent factors. This formulation can be directly entered into Strand7 using the Concrete Creep and Shrinkage User Defined option. Article 5.4.2.3.1 of AASHTO LRFD Bridge...

1.1 MB

ST7-1.20.40.16 Basic Material Nonlinear Analysis
This Webnote gives a brief summary of material nonlinear analysis and showcases a simple example. To start a material nonlinear analysis, a stress-strain curve is usually required. A typical stress-strain curve for low and medium carbon steels is shown below, with part of the curve exaggerated for clarity. For stresses up to the proportional limit, stress will be linearly proportional to the strain according to figure 1. If the stress exceeds the proportional limit then material nonlinear...

1.0 MB

ST7-1.20.40.17 Material Nonlinearity and Yield Criteria
Strand7 supports various linear, nonlinear and specialised material models suitable for modelling a range of different physical materials such as ductile metals, brittle concrete and soils. ...

1.0 MB

ST7-1.20.50.2 Nonlinear vs Linear Buckling Analysis
This Webnote examines the critical buckling load for four typical column configurations. Results from linear buckling analyses are compared with hand calculations using the familiar Euler equation in conjunction with effective length constants, which may be obtained from any text on elastic stability. Results from linear buckling analysis are then compared with those from a nonlinear buckling analysis. ...

0.4 MB

ST7-1.20.50.3 Modelling a Snap-Through Buckle
Buckling and post-buckling prediction is one useful applications of finite element analysis. A nonlinear buckling analysis can give a good indication of the structural response near the onset of buckling, and post-buckling if the solution can be made sufficiently stable. Snap-through buckling is one situation that exhibits stable post-buckling behaviour. This Webnote examines the prediction of snap-through buckling using Strand7. ST7-1.20.10.1 Nonlinear Elastic and Inelastic Buckling of a...

1.5 MB

ST7-1.20.60.1 Construction Sequence Analysis
Strand7 allows the modelling of construction sequence scenarios with sophisticated construction sequence tools. These tools have been designed to allow the user to easily model a staged construction such as a multi-storey building, a cable stay bridge, a staged excavation, a tunnel, an in-ground water tank, etc. For many structures it is important to understand how the structure will behave during its construction. The entire construction, excavation or deconstruction process can be simulated...

0.9 MB

ST7-1.20.60.2 Soil In-Situ Stress in Construction Sequence Analysis
Construction sequence analysis involving soil requires the consideration of the soil in-situ stress state in each of the defined analysis stages. When adding soil in a subsequent stage of a staged analysis (i.e. soil that is not present in the initial stage), the in-situ stress distribution of the added soil needs to be pre-computed. One minor consideration that may affect the results interpretation when adding soil is that existing soil can displace during the construction stage, before the new...

0.6 MB

ST7-1.20.60.3 Applying Pre Strain Attributes in Construction Sequence Analysis
This Webnote explores the handling of the element pre strain attribute in construction sequence (staged) analysis. In a staged analysis, the dimensions of an element at the beginning of a stage may be different to the as modelled mesh dimensions. The "initial" dimension depends on the Morph setting in the element's birth stage and the morphed element dimensions, which in turn affect the amount of contraction or expansion resulting from a pre strain attribute.