ABAQUS Advanced use

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ABAQUS Advanced use

• Element and Node Sets
• Shear Locking in solid elements
• Reduced Integration and Zero Energy Modes
• Sign Convention
• Integration Schemes
• Shell Elements pitfalls to avoid
• Beam Elements
• General Suggestions

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ABAQUS CAE - Modules

• PART Create part using
  Sketcher
• SKETCH sketcher
• ASSEMBLY Creation of instances and
  assembly.
• PROPERTY Define Material, SECTION
  Properties and
• ASSIGNS it.
  
  
• STEP Analysis Steps
• INTERACTION Interaction Properties,
  Constraints.
• Contact between
  2 surfaces,
• LOAD Loads, Boundary Conditions
  and Fields.
• MESH Choice of element
• JOB Creates Job, associates
  job with a MODEL
• VISUALIZATION Post processing

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Sign Convention

• Displacements and point loads are positive in the
  direction of the positive axes.
• Normal Stresses Tensile stress is ve.
• Shear stress anticlockwise about element centre
  is ve.
• Direct strains Tensile stress is ve
• Soils consolidation s s u

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Stress Discontinuities

• Stresses are calculated accurately at Gauss
  (Integration) points.
• Displacements are continuous across element
  boundaries.
• Stresses jump across element boundaries.

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Shell Element - Normal

• The direction of the ve normal is defined by the
  nodal sequence and the Right hand rule.
• The section points are numbered in the direction
  of the ve normal. The section points identify
  the sections.

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Parts and Instances

• Parts are the master components. These are
• not directly assembled.
• Instances are the copies of parts which make up
  the assembly.
• In the plate example the plate is the only part
  and is named Part-1
• Instance is a copy of the Part. It is the
  instances which form the assembly. If there is
  only a single part then the assembly consists of
  just the instance of the single part.

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What is the need for Instances?

• One might ask why there is a need for
  instances? Why not just have part (or parts)
• Which are assembled into the assembly?
• Instance in addition to containing all the
  information of the Part has information about its
  positioning in the assembly (using a translation
  and rotation vector).
• If the assembly contains multiple copies of
• a component (Part) then this is
  facilitated
• by having multiple instances of the part.

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Example of Instance

• Part, nameL-Plate
• Node
• 1, 15., 0., 30.
• 2, 15., 0., 0.
• Element, typeC3D8R
• 1, 577, 404, 461, 576, 2417,
  2244, 2301, 2416
• .
• End part
• ..
• ASSEMBLY
• Assembly, nameAssembly
• Instance, nameL-Plate-1, partL-Plate
• End Instance

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Example of Instance

• Part, nameL-Plate
• Node
• 1, 15., 0., 30.
• 2, 15., 0., 0.
• Element, typeC3D8R
• 1, 577, 404, 461, 576, 2417,
  2244, 2301, 2416
• .
• End part
• ..
• ASSEMBLY
• Assembly, nameAssembly
• Instance, nameL-Plate-1, partL-Plate
• End Instance

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Parts and Instances

• By default instances are dependent entities.
  Instances then inherit all the properties from
  the part (Example mesh
• section and material properties).
• However it is possible to make the instance
• independent when the instance is created.
  Then the instance can be meshed separately and
  assigned properties independent of the
• part. (Example two parts have minor
  differences).