Strand7 Webnotes

0.8 MB

ST7-1.20.20.3 Frame Dynamic Yielding and Static Pushover
A steel frame is subject to an earthquake load and also tested for pushover limits. The frame is composed of 200x200x10 mm I-beams. The coordinates of the frame (in metres) on the XY plane are shown at right. A translational mass of 2000 kg is placed at each node of the frame to represent supported mass. The two nodes at the base are fixed. The freedom case type is set as 2D Beam. The major units used in the model are: To define the nonlinear material behaviour of the beam (yielding)...

0.8 MB

ST7-1.20.20.9 Using Static Initial Conditions in Dynamic Analysis
Static solutions can be used as initial conditions in dynamic analyses to model systems which are pre-loaded but initially at rest; this considers the effect of an initial state of displacement and/or stress on the dynamic response. We will analyse a simple cantilever beam which sags due to self-weight (nonlinear static solution) and is then suddenly loaded to produce a dynamic response (nonlinear transient dynamic solution). We will first set up the dynamic model without static initial conditions...

0.4 MB

ST7-1.20.40.3 Plastic Beam Residual Stress
The Strand7 nonlinear material beam element uses either a moment-curvature table and axial stress-strain curve (R23x and prior) or a stress-strain curve only (R241 and later). To compare equivalent beam and shell models you must choose some analogous quantities. For stress, the beam fibre stress is analogous to the plate stress in the axial direction. The two cantilevered pipes are pushed past yield and subsequently relaxed to observe the resulting residual stress. The extrapolated nodal...

0.5 MB

ST7-1.20.40.5 Nonlinear Stress vs Strain Curves for Beam Elements
The Strand7 beam element is the most flexible element in terms of the nonlinear material behaviour it supports. Similarly to the plate and brick elements, the beam element supports both nonlinear elastic and elastic-plastic material behaviour. Unlike the plate and brick elements, the beam element also supports elastic-plastic behaviour that is different in tension and compression (plates and bricks support different tensile/compressive behaviour only for nonlinear elastic materials). This Webnote summarises the usage of Stress vs Strain tables for beam elements.

0.8 MB

ST7-1.30.20.1 Nonlinear Weld Mechanical Analysis
A quasi static nonlinear mechanical weld analysis is performed using thermal results and nonlinear Factor vs Temperature tables to calculate the mechanical response of a welded beam flange. This topic refers to the thermal results found in Webnote ST7-1.30.10.1 Nonlinear Weld Thermal Analysis. In this case we consider a short segment of steel web being welded to a flange. It is welded on both sides simultaneously in an attempt to avoid differential shrinkage deformation in the web. ...

0.4 MB

ST7-1.40.35.14 Modelling Nonlinear Behaviour of Steel Reinforced Concrete
Steel reinforced concrete beams and columns are composite structures consisting of two very different materials. Steel has high stiffness and yield in both tension and compression whereas concrete has little strength in tension (cracks under tension). These different nonlinear material behaviours can be captured using different material models and stress-strain curves in Strand7. In the modelling sense, steel reinforced concrete beams and columns can be modelled in a variety of ways including: ...

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ST7-1.50.40.5 Determining Appropriate Contact Stiffness
Contact is modelled in Strand7 using a special type of beam element. These beam elements react load nonlinearly, and in proportion to axial compression. The stiffness of these contact elements can affect the solution results accuracy and convergence. There are many physical situations that may be modelled with various configurations of contact elements. This Webnote aims to provide a guideline of what the axial stiffness value should be. Refer to ST7-1.57.20.8 Contact Element Fundamental...

0.4 MB

ST7-1.50.70.1 Beam End Release and Node Displacement in GNL Analysis
This Webnote describes the relationship between the beam end release results and nodal displacement for linear and geometric nonlinear (GNL) solution cases. The focus here is on the rotational end release attribute, but the discussion is also applicable to the translational end release attribute. The default joint condition for a beam element in Strand7 is that of a welded joint. Strand7 has two Beam End Release attributes: one is the translational end release and the other is the rotational...

0.6 MB

ST7-1.57.20.16 Comparison of the Moment Curvature and Fibre Stress Beam
Nonlinear material behaviour in beams can be modelled in Strand7 using a table defining the beam's moment-curvature behaviour or a table defining the material stress-strain behaviour. These methods are illustrated and compared in this Webnote by way of examples.

0.6 MB

ST7-1.70.70.1 Moment-Curvature Beam with Thermal Gradient Applied
When a moment-curvature nonlinear beam is used in conjunction with an applied beam thermal gradient, validating the moment-curvature relationship requires the consideration of the stress-free thermal curvature strain. The beam used in this example is shown below. It has a point load, thermal gradient, and support applied. The support is to stabilise the solution past the point of ultimate moment by providing an alternative load path after perfectly plastic hinging occurs. The total curvature...

Strand7 Webnotes - Search Results
0.8 MB	ST7-1.20.20.3 Frame Dynamic Yielding and Static Pushover A steel frame is subject to an earthquake load and also tested for pushover limits. The frame is composed of 200x200x10 mm I-beams. The coordinates of the frame (in metres) on the XY plane are shown at right. A translational mass of 2000 kg is placed at each node of the frame to represent supported mass. The two nodes at the base are fixed. The freedom case type is set as 2D Beam. The major units used in the model are: To define the nonlinear material behaviour of the beam (yielding)...
0.8 MB	ST7-1.20.20.9 Using Static Initial Conditions in Dynamic Analysis Static solutions can be used as initial conditions in dynamic analyses to model systems which are pre-loaded but initially at rest; this considers the effect of an initial state of displacement and/or stress on the dynamic response. We will analyse a simple cantilever beam which sags due to self-weight (nonlinear static solution) and is then suddenly loaded to produce a dynamic response (nonlinear transient dynamic solution). We will first set up the dynamic model without static initial conditions...
0.4 MB	ST7-1.20.40.3 Plastic Beam Residual Stress The Strand7 nonlinear material beam element uses either a moment-curvature table and axial stress-strain curve (R23x and prior) or a stress-strain curve only (R241 and later). To compare equivalent beam and shell models you must choose some analogous quantities. For stress, the beam fibre stress is analogous to the plate stress in the axial direction. The two cantilevered pipes are pushed past yield and subsequently relaxed to observe the resulting residual stress. The extrapolated nodal...
0.5 MB	ST7-1.20.40.5 Nonlinear Stress vs Strain Curves for Beam Elements The Strand7 beam element is the most flexible element in terms of the nonlinear material behaviour it supports. Similarly to the plate and brick elements, the beam element supports both nonlinear elastic and elastic-plastic material behaviour. Unlike the plate and brick elements, the beam element also supports elastic-plastic behaviour that is different in tension and compression (plates and bricks support different tensile/compressive behaviour only for nonlinear elastic materials). This Webnote summarises the usage of Stress vs Strain tables for beam elements.
0.8 MB	ST7-1.30.20.1 Nonlinear Weld Mechanical Analysis A quasi static nonlinear mechanical weld analysis is performed using thermal results and nonlinear Factor vs Temperature tables to calculate the mechanical response of a welded beam flange. This topic refers to the thermal results found in Webnote ST7-1.30.10.1 Nonlinear Weld Thermal Analysis. In this case we consider a short segment of steel web being welded to a flange. It is welded on both sides simultaneously in an attempt to avoid differential shrinkage deformation in the web. ...
0.4 MB	ST7-1.40.35.14 Modelling Nonlinear Behaviour of Steel Reinforced Concrete Steel reinforced concrete beams and columns are composite structures consisting of two very different materials. Steel has high stiffness and yield in both tension and compression whereas concrete has little strength in tension (cracks under tension). These different nonlinear material behaviours can be captured using different material models and stress-strain curves in Strand7. In the modelling sense, steel reinforced concrete beams and columns can be modelled in a variety of ways including: ...
0.5 MB	ST7-1.50.40.5 Determining Appropriate Contact Stiffness Contact is modelled in Strand7 using a special type of beam element. These beam elements react load nonlinearly, and in proportion to axial compression. The stiffness of these contact elements can affect the solution results accuracy and convergence. There are many physical situations that may be modelled with various configurations of contact elements. This Webnote aims to provide a guideline of what the axial stiffness value should be. Refer to ST7-1.57.20.8 Contact Element Fundamental...
0.4 MB	ST7-1.50.70.1 Beam End Release and Node Displacement in GNL Analysis This Webnote describes the relationship between the beam end release results and nodal displacement for linear and geometric nonlinear (GNL) solution cases. The focus here is on the rotational end release attribute, but the discussion is also applicable to the translational end release attribute. The default joint condition for a beam element in Strand7 is that of a welded joint. Strand7 has two Beam End Release attributes: one is the translational end release and the other is the rotational...
0.6 MB	ST7-1.57.20.16 Comparison of the Moment Curvature and Fibre Stress Beam Nonlinear material behaviour in beams can be modelled in Strand7 using a table defining the beam's moment-curvature behaviour or a table defining the material stress-strain behaviour. These methods are illustrated and compared in this Webnote by way of examples.
0.6 MB	ST7-1.70.70.1 Moment-Curvature Beam with Thermal Gradient Applied When a moment-curvature nonlinear beam is used in conjunction with an applied beam thermal gradient, validating the moment-curvature relationship requires the consideration of the stress-free thermal curvature strain. The beam used in this example is shown below. It has a point load, thermal gradient, and support applied. The support is to stabilise the solution past the point of ultimate moment by providing an alternative load path after perfectly plastic hinging occurs. The total curvature...