Structural Mechanics

Beam and Shell

A number of new capabilities enhance structural analysis.

Shear-moment diagram results displayed along length of beam models

Restart for Nonlinear Simulation

The ANSYS Workbench platform delivers solutions that provide ease of use and productivity even for complex nonlinear simulations. ANSYS 13.0 introduces the ability to perform restarts on nonlinear simulations.

For example, if the solver stops because of convergence issues or the user needs to check intermediate results, the entire solution no longer needs to be recomputed from beginning to end.

Restart analysis and restart controls are included in the analysis settings for static structural and transient structural analyses. This capability allows the analysis to be restarted under a variety of conditions, such as time step changes. These restart points can be managed in the timeline and tabular data windows. Jobs can be interrupted and restarted for local, RSM and distributed solutions.

Controls for establishing restart points

Cyclic Symmetry Analysis

Many companies in the turbine industry require cyclic symmetry analysis functionality. For many years, ANSYS structural solutions have allowed patterned geometries (also called cyclic symmetry models) to be computed using only a sector of the model. ANSYS 13.0 now exposes the capability in the ANSYS Mechanical environment.

Results of single sector revolved 360 degrees

Nonlinear Simulation

Most engineering simulation applications require nonlinearities of some kind, such as contact or materials. The ANSYS focus on nonlinear capabilities delivers easy-to-use, advanced and robust tools so these simulations can be performed as easily as linear analyses.

With ANSYS 13.0, a prestressed modal basis at any load step of a linear or nonlinear model can be computed. In previous releases, only linear states were considered for computation of the modal basis (eigenvectors and frequencies).

Release 13.0's underlying technique is called linear perturbation, which has been developed in the core solver and is available to ANSYS Workbench users. The technique radically differs from the method (based on PSOLVE and other APDL commands) previously used to compute nonlinear prestressed modal analyses.

In setting up the nonlinear and prestressed modal analysis, the user process is the same except the choice of the time step.

Prestressed modal created for multiple simulation points

Tightly Coupled FSI

To accurately model the interaction between fluids and solids, it is best to use two different solution methods that are tightly coupled and directly communicate as the simulation progresses. Fluids and gases are best handled with a method called Euler, while structures are handled by the Lagrange method. The interaction between the two parts is called Euler–Lagrange coupling, or fluid–structure interaction (FSI). The coupled method handles boundary interactions between the two parts of the same problem.

FSI is now available to users of the ANSYS Explicit Dynamics solver with one mouse click. When the user indicates that the fluid part of the problem's reference frame is Euler, the virtual Euler domain is automatically created. For users of ANSYS Mechanical within the ANSYS Workbench environment, the model definition is very similar to an implicit simulation, making it is easy to learn and use.

Fluid sloshing in container

Variational Technology

Variational technology (VT), an innovative way to compute simulation results faster, has been extended in ANSYS 13.0 to frequency sweeps and the computation of modes in the case of cyclic symmetry problems.

Typical speedup ratios found with such problems range from five to 10. Higher ratios can be achieved when there are more steps in the frequency range or more indexes required for the cyclic symmetry.

Variational technology also can be used for thermal transient runs and parametric variations. This capability was introduced in earlier releases.

VT harmonic analysis computes results faster

3-D Rezoning

This unique feature is provided within ANSYS structural mechanics solutions for materials that exhibit extreme shape deformation, such as plastic, rubber and foam.

Traditionally it has been difficult to arrive at an accurate solution. When very large deformations are encountered, the low quality of the distorted mesh might prevent obtaining a solution over the entire time range. In that case, the simulation needs to be stopped, the volume remeshed in its current state, and the simulation continued after all quantities have been remapped, including contacts, material property assignment, loads and boundary conditions.

The new 3-D rezoning solution mapper technology automatically handles contact and boundary conditions mapping from the old mesh to a new mesh. This solves the model to the limit of confident accuracy.

3-D Rezoning

Rigid Body Dynamics 3-D Generalized Contact

Fully rigid simulations (in which no stresses or strains are computed) provide a quick and efficient way to determine forces and relative motions of a mechanism. However, a mixed rigid–flexible approach is needed to determine how stresses evolve in some members of a mechanism — a capability useful for predicting life estimates.

The ANSYS Workbench platform provides unparalleled ease of use when setting up a rigid–flexible model. The user simply indicates which bodies are considered as flexible and which ones are considered as rigid. The Rigid Body Dynamics module from ANSYS is used for computing mechanisms and the interaction between bodies. In many mechanisms, the probability for the motion of some parts to be contact driven is very high. One example is a cam-driven mechanism.

With ANSYS 13.0, the Rigid Body Dynamics add-on supports 3-D generalized contact. Contact detection is performed automatically, as with any other structural analysis, and the solver ensures proper detection of the impacts.

Kinematics capabilities — which include configure and redundancy tools to determine if a model is set up properly by dynamically checking joints and to examine redundancies, respectively — are now available in most ANSYS structural mechanics solutions.

Rigid body dynamics analysis of cam follower (top) and flexible body dynamics of vehicle suspension (bottom)

Design Assessment System

A new analysis system called design assessment is available with ANSYS structural mechanics products to allow management of load combinations and customized post-processing (such as code checks) based on ANSYS programs or the users' own programs.

The design assessment system enables the selection and combination of upstream results along with an optional ability to further assess results with customizable scripts. It allows the user to associate attributes, which may be linked by geometry but are not necessarily a property of the geometry, to the analysis via customizable items that can be added in the tree. Custom results can be defined from a script and presented in the design assessment system to enable complete integration of a post-finite element analysis process. The scripting language supported is python-based. Script location and available properties for the additional attributes and results can be defined via an XML file, which can be created easily in any text editor and then selected by right-clicking on the system's setup cell.

A user can add this release 13.0 feature to a static structural or transient structural analysis. Predefined scripts are supplied to interface with the ANSYS BEAMCHECK and ANSYS FATJACK products.

Selection of ANSYS BEAMCHECK assessment type (top) and example of joint unitary check result visualization (bottom)

HPC with GPUs

Committed to providing the most advanced and modern high-performance solutions, ANSYS monitors the evolution of hardware to leverage its power for customers. The overarching goal is to reduce time to solution.

ANSYS 13.0 leverages the power of graphics processing units (GPUs) to offload heavy number-crunching algorithms onto more powerful GPU cards, which are capable of performing general-purpose computations using double-precision accuracy. This capability is available for the ANSYS Mechanical and Nexxim solvers.

Multiphysics

External Data Mapper

ANSYS continues to align Simulation Driven Product Development with real-world business challenges. At many organizations, engineers from different disciplines work on a single design, often using different tools. Those working independently on CFD often need to exchange data with those working on structural analyses — for example, when CFD pressures are applied to a structural model.

With ANSYS 13.0, the new external data mapper imports external data in the form of a text file defining a point cloud and the data to be projected onto the current mesh. The external data mapper allows users from different groups (such as CFD and structural) to exchange model data in a straightforward manner. It also provides the capability to import data from third-party applications. Body temperatures, surface pressures and heat transfer coefficient can be easily mapped from a data source onto a new simulation. The user can define the units for the data to be imported and align the imported data using current geometry. Visual controls identify how the point cloud data is aligned with the model. Data mapping works from 3-D data to 3-D geometry as well as from 2-D data to 3-D geometry.

Point cloud temperature interpolation on turbine blade

Electromagnetic–Structural Coupling

This feature has been enhanced through tight ANSYS Workbench project schematic integration between the Maxwell and ANSYS Mechanical solvers. Maxwell passes electromagnetic force densities to the ANSYS Mechanical solver within the ANSYS Workbench environment. Forces are mapped automatically across a dissimilar mesh interface to the structural model, and the structural solution is performed including the electromagnetic force densities. This new capability allows users to calculate mechanical deformations and stresses for a wide range of electromechanical applications, including electric motors, transformers and superconducting magnets. The entire coupled solution is parametric, which allows for fast and easy evaluation of many designs.

Electromagnetic–structural coupling for hybrid vehicle motor stator

Electromagnetic–Thermal Coupling

Electromagnetic–thermal coupling has been enhanced through tight ANSYS Workbench project schematic integration between the HFSS and ANSYS Mechanical solvers. HFSS passes electromagnetic losses to the ANSYS Mechanical solver. Both surface and volumetric losses are mapped automatically across a dissimilar mesh interface to the mechanical mesh, and the thermal is performed including the electromagnetic losses. This new capability allows users to calculate the thermal response for a wide range of RF and microwave components. The entire solution is parametric, which allows for fast and easy evaluation of many designs.

Electromagnetic–thermal coupling for high-power connector using ANSYS Workbench

Multiphase Flow

ANSYS FLUENT is a leader in multiphase modeling technology. Its varied capabilities allow engineers to gain insight into equipment that is often difficult to probe. 

ANSYS FLUENT software makes use of the Eulerian multiphase model with its separate sets of fluid equations for interpenetrating fluids or phases, as well as a more economical mixture model. Both models can also handle granular flows. 

Several other multiphase models are standard in ANSYS FLUENT. For some multiphase applications such as spray dryers, liquid fuel sprays, continuous fiber drawing and coal furnaces, the discrete phase model (DPM) can be used. Both the volume of fluid model and the coupled level-set model are available for free surface flows, such as bubble flow, in which the prediction of the interface is of interest. The cavitation model has proven useful for robustly modeling hydrofoils, pumps and fuel injectors. Several population balance models are available for modeling size distributions.

Bubbles in a fluidized bed

Fluid Dynamics

Turbulence Models

ANSYS 13.0 contains many new and improved turbulence models that allow physical phenomena to be captured more accurately.

Fully developed channel flow simulated with embedded LES

Unphysical wiggles (left) can be prevented (right) with the BCD scheme in scale-resolving simulations

Wake structure behind F-1 car wheel simulated with SAS

Mesh Swapping and Remeshing

New capabilities have been introduced to increase accuracy using better mesh quality.

Mesh swapping used for in-cylinder engine simulation

Cartesian remeshing for in-cylinder engine simulation

Multiphase Flow

Additional multiphase capabilities have been added to ANSYS 13.0 to address more applications with greater reliably and accuracy as well as to meet users' evolving CFD needs.

Contours of vapor volume fraction in nuclear fuel assembly

Accumulation of sand models using packing limits in DDPM

Comparison of several breakup models (including KHRT) with experimental data

Solid Motion and Temperatures

Various capabilities have been added to ANSYS 13.0 that address reliability and accuracy.

Airflow around F-1 car using MRF

Fluid (left) and solid (right) temperature fields in catalytic converter

Design Optimization

Parametric studies help companies design better products or obtain an in-depth understanding of product behavior. Automatic shape flow optimization for fluid dynamics analysis uses gradient information, mesh-morphing technology and an optimizer that are all integrated into the ANSYS FLUENT solver. In one case study, the design criterion was to automatically determine channel shape for which the outflow velocity would be most uniform. The original design incorporated straight sides, and the resulting outflow was nonuniform. The ANSYS FLUENT automatic shape flow feature then determined that a curved shape provided a more uniform outlet velocity profile.

Automatic shape flow optimization

Data and Process Management

Workflows or simulation processes are sequential tasks connected with actions that lead to successful completion of the simulation. The tasks could be assigned to simulation expert staff or machine resources, such as compute clusters.

ANSYS Engineering Knowledge Manager (ANSYS EKM) software handles such CAE-focused collaborative workflows very effectively. New to ANSYS 13.0, ANSYS EKM Studio software defines such workflows, and the process player in ANSYS EKM allows execution of the workflow in a user-friendly way. It captures the process-related information, inputs and decisions automatically. This is useful for audit purposes.

ANSYS Workbench Framework

Improved Evaluation of Multiple Design Points

Building on the strength of ANSYS Workbench parametric simulation, the efficiency of design point updates has been improved. First, when updating a design point, only those systems and components required to bring all output parameters up to date are calculated. Adding systems or making changes that do not affect those output parameters will not cause design points to go out of date.

When complex projects involving multiple physics are calculated, output parameters are shown as they are calculated. This improves feedback and provides more information in cases where a design point is only partially up-to-date.

A new option has been added to update design points in order, which can avoid unnecessary regeneration of the mesh when subsequent design points use the same geometric configuration.

Example of a parametric design point in ANSYS Workbench

ANSYS DesignXplorer Accuracy

When performing sensitivity analyses or optimization based on response surface techniques, the user needs to determine the accuracy of the response surface and, therefore, the trustworthiness of the approximation. A good approximation is required to extract meaningful results from sensitivity studies. Several new features in ANSYS DesignXplorer software reinforce the accuracy of the results.

New design of experiment (DOE) schemes are now available. Sparse grid, for example, is a dynamic DOE response type that features automatic adaptive refinement. This capability adds design points based on response surface gradients until the relative error drops below a certain threshold.

Accuracy can be checked visually by using these sampling points (from the design of experiments) in combination with additional verification points. These points are plotted against the estimated response surface. Points close to the diagonal are more accurate when compared with the response surface.

Automated adaptive refinement (top) and accuracy assessment (bottom) using ANSYS DesignXplorer

Microsoft Excel Interoperability

Microsoft® Excel® is one of the most widely applied tools for engineering. With ANSYS 13.0, the ANSYS Workbench platform can interact directly with Microsoft Excel spreadsheets.

For parametric analysis with the ANSYS DesignXplorer tool, it is possible to import a table of parametric configurations from Microsoft Excel into ANSYS Workbench for subsequent execution of DOE studies.

In addition, an Excel component system is available within ANSYS Workbench that can enable Excel to exchange parameters with the ANSYS Workbench project. Parameters can easily be flagged in Excel using the "name a range" method and values from those cells are then exchanged as ANSYS Workbench input or output parameters. In this way, optimization can be conducted based on Excel-calculated parameters, such as cost. In addition, the Excel system can introduce a reduced-order model (ROM) coupled with parameters from other systems in the project schematic.

Microsoft Excel spreadsheet linked to ANSYS Workbench project

Extending the Reach of the Remote Solve Manager (RSM)

The Remote Solve Manager (RSM) is a tool for job queuing and remote job submission that has been in use for several releases with the ANSYS Mechanical application. At ANSYS 13.0, it has been extended for use with other solvers, so that the most computationally intensive simulation task, the solver update, can be queued to wait for available computing resources, potentially on remote machines. This capability has also been made available for the update of design points. By getting the computational heavy lifting off the desktop workstation, engineering productivity can be greatly enhanced.

Engineering Design

ANSYS CFD-Flo software addresses the fluid flow analysis needs of designers who work on the front lines of their company’s product development process. The tool provides access to the physics models most commonly used by design engineers, and it is compatible with other applicable ANSYS Workbench platform add-ins. The reduced complexity and cost of ANSYS CFD-Flo make it a good choice for design departments.

ANSYS CFD technology delivers the ability to perform in-depth analysis of fluid mechanics in many types of products and processes. Not only does it reduce the need for expensive prototypes, it provides comprehensive data that is not easily obtainable from experimental tests. Fluid simulation can be used to complement physical testing. Some designers use fluid dynamics simulation to analyze new systems before deciding which validation tests, and how many, need to be performed. When troubleshooting, problems are solved faster and more reliably because fluid dynamics analysis highlights the root cause, not just the effect. When optimizing new equipment designs, many what-if scenarios can be analyzed in a short time. This can result in improved performance, reliability and product consistency.

Gas and solids distribution in a three-phase bubble column as calculated using the Eulerian multiphase flow model. The light-blue iso-surface shows the region with the highest gas fraction. The color on the column wall indicates the concentration of the solid catalyst particles. The solids are not well mixed. ANSYS CFD software can be used to determine the optimum operating conditions for these reactors.

Electromagnetics

HFSS Transient Solver

This solver, based on the discontinuous Galerkin time domain (DGTD) method, uses an unstructured, geometry-conforming mesh to accurately simulate complex geometries. Computer memory usage is modest because the underlying method doesn't require the solution of a large matrix equation. It has an innovative local time stepping procedure that optimizes runtime, stability and efficiency.

The HFSS transient solver can handle complicated and curved geometries because of the flexibility of the unstructured meshes used in DGTD. The new method provides powerful significant advantages over simulation by conventional brick-shaped FDTD and FIT meshers.

Applications using HFSS transient capability: EMI study (left) and lightning strike (right)

Hybrid Equation Solver

ANSYS 13.0 introduces the first commercial code that performs a hybrid solution between finite element methods (FEM) and integral equation (IE) methods for high-frequency electromagnetics problems. In the FEM method, the FEM volume must be truncated into an outer surface. This traditionally has been a type of absorbing boundary condition (ABC). Though ABC is a good absorber, it is not a perfect absorber. Hybridizing the code provides a perfect absorber and highly accurate fields. The IE surface can be placed very close to the surface and can have convex shape conforming to the structures. This minimizes the volume and speeds the solution.

Radar cross section of wind turbine

HSPICE Integration

Ansoft Designer software has been linked to the popular circuit simulator from Synopsys, HSPICE. This configuration provides a powerful user interface and direct links to electromagnetics software such as HFSS and SIwave. As a result, users can now quickly and accurately analyze signal-integrity, power-integrity and electromagnetic interference (EMI) problems from a single schematic- and layout-based environment.

Ansoft Designer linking HFSS with HSPICE

Meshing

CutCell Meshing

CutCell meshing is a general-purpose meshing technique that produces almost all hexahedral elements on complex 3-D geometry automatically. This meshing algorithm is suitable for a large range of applications, is useful for meshing fluid bodies in both single and multibody parts, and is very easy to set up.

Hexahedral mesh automatically generated for F-1 car

Virtual Split Edge

While automated meshing is important for speedy solutions, engineers require advanced meshing controls to allow interaction with the model. Using both automated and manual meshing techniques can maximize productivity.

The new virtual split edge feature, part of the virtual topology tool for the simulation application, allows splitting of one edge into two virtual edges. The user can define the location of the split either by picking the location in the geometry window or by specifying a numerical value in the details view. This new feature brings several new capabilities:

Vertice definition (left) and controlled mesh (right) produced with virtual split edge feature