Lesson: Plasticity hardening in Abaqus
This lesson is all about understanding hardening in Abaqus and getting hands-on with practical simulations. We’ll dive into the basics of hardening, its types, and the equations that define them. Along the way, you’ll explore fascinating concepts like the Bauschinger effect, cyclic hardening with shakedown, ratcheting, and stress relaxation. By the end, you’ll learn how to create complete models, define kinematic and combined hardening, apply earthquake load histories, troubleshoot convergence issues, and extract results for plotting hysteresis curves. It’s a straightforward, step-by-step guide to mastering hardening concepts in Abaqus with real-world applications.
Workshop I: effect of the earthquake on a brace with kinematic curve
In this workshop, the effect of the earthquake on a brace or applying a kinematic curve and applied load in the top section are examined.
Workshop II: Combined hardening usage in structure under cycling loading
A combined hardening behavior with applying force on the lower section is investigated in this workshop.
Workshop III: Writing VUMAT Subroutine for Kinematic Hardening Plasticity
In this Abaqus VUMAT tutorial, kinematic hardening is illustrated using graphical explanations, and the governing equations are introduced. The required equations for use in the subroutine are derived, including those for internal and dissipation energy. A step-by-step flowchart for implementation is then presented and explained. The subroutine is thoroughly detailed line by line before being implemented in Abaqus. Finally, the subroutine is validated by comparing its results with those obtained from Abaqus.
Workshop IV: Implementation of UHARD Subroutine for isotropic hardening (formulation based) in simple model
In the first workshop, a cube with dimensions “L” is used as the model. One side of the cube is fixed, while a displacement “U” is applied to the other. The hardening in this workshop is based on formulations, meaning you need to define the appropriate formula within the subroutine before implementing it.
Implementation of the Lemaitre Damage Model with the VUMAT Subroutine
This training package covers the Lemaitre damage model, widely used for coupled damage analyses in various mechanical applications. The concept of damage is first introduced through a literature review, highlighting that the Lemaitre model addresses damage occurring alongside plastic deformation. The coupled yield and damage equations are then presented in detail.
The package begins by explaining the fundamentals of the Lemaitre damage model, including its mechanics and formulation. Next, it provides a step-by-step guide to writing the subroutine, starting with the flowchart, then coding it line by line, implementing it for a single element, and verifying the results. Finally, the subroutine is applied to a complex problem, such as an upsetting process.
The operator split method is used to solve the model’s equations, and the elastic and plastic deformation laws are explained thoroughly. Guidance is provided on incorporating these laws into the subroutine.
Additionally, the flowchart for the VUMAT subroutine is presented, along with details on required inputs and outputs. Key state variables—such as equivalent plastic strain, the damage parameter, and element deletion—are discussed, with an emphasis on how to use them to interpret the subroutine’s outputs effectively.
Workshop-1: cyclic loading simulation in steel beam-column structure reinforced with CFRP
This tutorial explores the simulation of cyclic loading on a steel beam-column structure reinforced with CFRP in Abaqus. The steel beam and column are modeled as 3D shell parts, while the CFRP plates are modeled as planar shell parts. To simulate the behavior of steel under cyclic loading, the combined plasticity model is used, allowing for accurate prediction of material behavior during each cycle. For the CFRP material, engineering constants elasticity with Hashin’s damage criterion is applied.
The analysis employs a general static step with adjustments to the convergence model. Perfect contact is assumed between the steel beam, column, and CFRP sheets. Fixed boundary conditions are applied at the top and bottom of the steel column, while displacement with an amplitude (based on a loading protocol) is applied to the steel beam’s end. A fine mesh ensures high accuracy in the results. After running the simulation, results such as stress, strain, displacement, and the hysteresis diagram can be obtained.
Workshop-2: flexural behavior simulation of CFRP steel beam reinforced
This tutorial examines the simulation of the flexural behavior of a steel beam reinforced with CFRP using Abaqus. The steel beam and CFRP sheet are represented as three-dimensional shell elements, while the rigid bodies are modeled as discrete rigid bodies.
Fiber-reinforced polymer (FRP) materials consist of an epoxy matrix embedded with fiber reinforcement. These materials are increasingly used for the strengthening and rehabilitation of concrete structures due to their advantageous properties, including a high strength-to-weight ratio, resistance to corrosion, and excellent fatigue performance. Common types of FRP composites used for structural reinforcement include Glass FRP (GFRP), Carbon FRP (CFRP), and Aramid FRP (AFRP). Numerous studies have explored the application of CFRP composites in reinforcing steel beams. However, some challenges associated with CFRP include its brittle failure characteristics and the risk of galvanic corrosion when used in steel structures.
In the simulation, the steel beam is modeled with elastic-plastic behavior incorporating a ductile damage criterion, while the CFRP material is defined using elastic properties and Hashin’s damage criterion. These material models facilitate the prediction of damage under static loading and bending conditions. The analysis is conducted using a general static simulation with adjustments to the convergence model. A surface-to-surface contact model is applied between the rigid parts, the steel beam, and the CFRP, assuming a perfect bond between the steel beam and CFRP. Fixed boundary conditions are set at the bottom rigid bodies, while displacement-based loading is applied to the two top rigid bodies. A refined mesh is necessary to ensure accurate results.
Following the simulation, various results can be obtained, including stress, strain, damage distribution, and a Force-Displacement diagram. The maximum load-bearing capacity can be determined from the Force-Displacement curve.
Workshop-3: Shear failure analysis of structure with bolt connection
This tutorial focuses on simulating the shear failure of two steel plates connected by bolts in Abaqus. The steel plates and bolts, modeled as 3D solid parts, utilize an elastic-plastic material model. To predict damage and failure, both ductile and shear damage criteria are applied. The ductile criterion predicts damage onset due to void nucleation, growth, and coalescence, while the shear criterion addresses damage caused by shear band localization.
A dynamic explicit step is used to simulate the dynamic load applied as tension to the upper plate. Surface-to-surface contact with defined contact properties is set for all interaction domains. Fixed boundary conditions are applied to the bottom plate, and a smooth displacement amplitude is applied to the upper plate. To ensure accurate results, partitions are created for each bolt, and a fine, appropriate mesh is used to capture the correct failure mode and shape.
After the simulation, results such as stress, strain, damage, and failure patterns can be obtained. Under the applied load, the upper plate experiences complete damage and failure.
Workshop-4: Damage analysis of steel beam-column structure in cyclic loading
This tutorial focuses on simulating cyclic loading and damage investigation in a steel beam-column structure using Abaqus. The beam and columns are modeled as 3D shell parts. To simulate the steel behavior under cyclic loading, elastic-isotropic plasticity coupled with a ductile damage criterion is used for better damage prediction. While kinematic or combined plasticity models can be applied, isotropic plasticity paired with ductile damage provides more accurate results.
The analysis employs a general static step, with modifications to the convergence model to prevent early non-convergence issues. Perfect contact is assumed between the beam and columns, and the general contact algorithm is used to address any interference during the simulation. Fixed boundary conditions are applied to the column bases, and a cyclic displacement protocol is assigned as an amplitude for the columns. A fine mesh is critical for accurate results.
After running the simulation, results such as stress, strain, damage, failure patterns, and the force-displacement diagram can be obtained.
Workshop-5: Dynamic and failure analysis of bolt in steel plates joint
This tutorial examines the simulation of dynamic bolt failure in a bolt and steel plates joint using Abaqus. Both the upper and bottom steel plates, as well as the bolts, are modeled as 3D solid parts. Two primary mechanisms are considered for the fracture of ductile metals: ductile fracture caused by void nucleation, growth, and coalescence, and shear fracture resulting from shear band localization. Corresponding ductile and shear damage criteria are applied to predict the onset of damage during the simulation.
The dynamic explicit step, combined with a mass-scaling technique, is used to model the dynamic failure of the bolts. Surface-to-surface interaction is defined with properties like friction to account for contact behavior. Fixed boundary conditions are applied to both sides of the bedplate, while a smooth displacement amplitude is used to apply load to the upper steel plate. A fine mesh is essential for accuracy, and multiple partitions are created to achieve proper meshing.
After the simulation, results such as stress, strain, damage, failure, and displacement can be analyzed.
Workshop-6: Failure Simulation of steel bolted double angle connections in dynamic loading
This tutorial focuses on the simulation of steel bolted double-angle connections under dynamic loading in Abaqus, with a focus on failure analysis. The beam, column, and bolts are all modeled as 3D solid parts. Connections play a vital role in maintaining the stability of steel structures by ensuring continuity of load paths between elements. All parts use grade 14 steel with an elastic-plastic material model. The ductile damage criterion is applied to predict damage and failure in the bolts and beam, allowing for damage observation after the simulation.
The dynamic explicit step is used for this analysis, along with a mass-scaling technique to reduce simulation time and stabilize the model. Surface-to-surface contact is defined with specific contact properties, and rough contact is applied to the bolt connections. Fixed boundary conditions are applied to both ends of the column, while displacement is applied to the beam’s end. Fine meshing is critical, especially in contact zones, and partitions are used to ensure high mesh quality.
After the simulation, results such as stress, strain, damage, and failure can be obtained and analyzed.
Workshop-7: Implicit damage analysis of steel beam structure in cyclic loading
This tutorial explores the simulation of steel beam damage under cyclic loading in Abaqus Standard. Under cyclic loading, such as earthquake ground motions, local buckling occurs in the compression flange, disappearing and reappearing in subsequent cycles.
The beam is modeled as a 3D shell part, using a linear elastic, isotropic plasticity material model with a damage parameter to analyze damage distribution. A general static step is employed for this analysis, and the cyclic load is applied as a protocol to the beam’s tip. Fine mesh quality is essential to improve simulation accuracy.
During the simulation, stress, strain, and damage distribution on the beam are observed, providing valuable insights into its behavior under cyclic loading.
Workshop 8: Finite element simulation of composite joints in beams and steel–concrete
This tutorial investigates the numerical simulation of steel-concrete joints and composite beams. The model includes a concrete slab, steel sheet, steel beams, and rigid bodies. The Concrete Damage Plasticity (CPD) material model is used for the concrete, while an elastic-plastic model is applied to the steel. A dynamic explicit step with smooth amplitude is used to apply a smooth load.
Surface-to-surface contact is defined for the interactions between the rigid bodies and the concrete slabs, while perfect contact is assumed between the steel sheet and concrete. Beam elements are used to model the joint between the steel beam and sheet, which becomes a critical point when the stress reaches its peak. Boundary conditions are applied to the rigid bodies, and a high-quality mesh is necessary to ensure accurate results.
After running the simulation, results such as maximum stress, strain, and tensile/compressive damage can be obtained.
Workshop 9: steel-concrete composite column analysis in different loading types (vertical and horizontal loading)
This tutorial explores the simulation of steel-concrete composite columns under vertical and horizontal loads in Abaqus. Steel-concrete composite columns are advanced composite structures widely used for their high load-bearing capacity, efficient material usage, high stiffness, ductility, and large energy absorption capabilities. By combining reinforced concrete (RC) and structural steel, these columns offer several advantages over traditional reinforced concrete and steel members, such as fire resistance for the steel and preventing buckling. However, SRC columns require both longitudinal and transverse reinforcement to prevent concrete spalling when subjected to axial loads, fire, or earthquakes.
In the model, the concrete column and steel beam core are represented as 3D parts, with the bar modeled as a wire and the pusher plate as a rigid body. An elastic-plastic material model with a ductile damage criterion is used for the steel, while the Concrete Damage Plasticity (CDP) model is applied to the concrete column. Both general static and dynamic explicit procedures are used separately, and the results are compared at the end of the simulations. Perfect contact is assumed between the concrete and steel beam, with the bars embedded in the concrete. A vertical concentrated force is applied to the top surface of the column, and a pressure load is applied to the side surface of the concrete.
After completing both static and dynamic simulations, results such as stress, strain, damage, displacement, and the force diagram can be obtained.
Workshop 10: Damage analysis of steel column with stiffeners in cyclic loading
This tutorial investigates the simulation of cyclic loading on a steel column with stiffeners in Abaqus, with a focus on damage analysis. The box column is modeled as a 3D shell part, and the stiffeners are modeled as a planar shell part. The stiffeners are placed at the column’s end, acting as a weld zone to strengthen it. They are designed to shift the damage zone from the column’s end to a different location. While kinematic or combined plasticity models are typically used to capture cyclic behavior due to their variable yield surfaces, this simulation focuses on identifying the damage and failure locations, so isotropic plasticity with a ductile damage criterion is used instead. The ductile damage criterion helps predict the damage zone under cyclic loading.
A general static step is used for the analysis. The end of the column and the bottom edges of the stiffeners are treated as a weld zone, applying fixed boundary conditions. A cyclic loading protocol is used to define the load amplitude. A fine mesh is essential to improve result accuracy. The results show how the failure or damage zone shifts from the column’s end to a higher position due to the stiffeners’ effect. All results, including stress, strain, and damage, can be obtained.
dave –
Thank you for posting the demo photos of this package, now I am sure to buy this package. Thank you for doing the same for other packages on the site.
pablo –
This package was good and with great education and went through every detail. thanks
jakub.min –
The course is made in such a way that even person with no knowledge of the software can comprehend and produce models.
Are all your tutorials like this?