StressCheck
Encyclopedia
StressCheck is a finite element analysis software product developed and supported by ESRD, Inc. of St. Louis, Missouri
. It is one of the first commercially available FEA products to utilize the p-version of the finite element method
.
, and Mr. Kent Myers. The principals have been performing research and development related to p-version finite element analysis for more than 20 years. Close ties to the Washington University Center for Computational Mechanics
facilitates incorporation of the latest research results into StressCheck.
and heat transfer, and utility modules that offer functionality to import CAD models and perform 2D and 3D automatic meshing. Below is an abbreviated summary of current analysis modules and general capabilities.
. The utilization of the p-version in finite element analysis was pioneered by Dr. Barna Szabó during his tenure at Washington University in St. Louis
. The p-version finite element method spans a space of high order polynomials by nodeless basis functions, chosen approximately orthogonal for numerical stability. Since not all interior basis functions need to be present, the p-version finite element method can create a space that that contains all polynomials up to a given degree with many fewer degrees of freedom.
In practice, the name p-version means that accuracy is increased by increasing the order of the approximating polynomials (thus, p) rather than decreasing the mesh size, h. Thus, to check for solution convergence by increasing the number of degrees of freedom in a given model, the shape function polynomial level is increased rather than remeshing with more elements, which is the standard FEA tool method. In StressCheck the maximum p-level is set to eight (8).
, and for a range of applications such as aircraft damage tolerance
assessment and analysis of composite materials for which high order elements are particularly useful.
St. Louis, Missouri
St. Louis is an independent city on the eastern border of Missouri, United States. With a population of 319,294, it was the 58th-largest U.S. city at the 2010 U.S. Census. The Greater St...
. It is one of the first commercially available FEA products to utilize the p-version of the finite element method
Finite element method
The finite element method is a numerical technique for finding approximate solutions of partial differential equations as well as integral equations...
.
History
Development of StressCheck software began shortly after the founding in 1989 of ESRD, Inc. by Dr. Barna Szabó, Dr. Ivo BabuškaIvo Babuška
Ivo M. Babuška is a Czech-American mathematician, noted for his studies of the finite element method and the proof of the Babuška-Lax-Milgram theorem in partial differential equations. One of the celebrated result in the finite elements is the so-called Babuska-Brezzi condition, which provides...
, and Mr. Kent Myers. The principals have been performing research and development related to p-version finite element analysis for more than 20 years. Close ties to the Washington University Center for Computational Mechanics
Washington University School of Engineering and Applied Science
The Washington University School of Engineering is a part of Washington University in St. Louis. Founded in 1854, the engineering school is a world-class research institution occupying seven buildings on Washington University’s Danforth Campus...
facilitates incorporation of the latest research results into StressCheck.
Capabilities
StressCheck is a complete 3D finite element analysis tool with an integrated pre- and post-processor, a suite of analysis modules supporting advanced solutions in elasticityElasticity (physics)
In physics, elasticity is the physical property of a material that returns to its original shape after the stress that made it deform or distort is removed. The relative amount of deformation is called the strain....
and heat transfer, and utility modules that offer functionality to import CAD models and perform 2D and 3D automatic meshing. Below is an abbreviated summary of current analysis modules and general capabilities.
Pre-Processing
- Fully parametric modeling capability, including parameter- or formula-controlled:
- Geometric dimensioning
- Meshing parameters
- Material properties
- Boundary conditions (loads and constraints)
- Tractions can be directly applied to the model to meet the requirements of elasticityElasticity (physics)In physics, elasticity is the physical property of a material that returns to its original shape after the stress that made it deform or distort is removed. The relative amount of deformation is called the strain....
- Intrinsic capability to represent sinusoidal bearing loads
- Support for a wide variety of constraint conditions
- Tractions can be directly applied to the model to meet the requirements of elasticity
- Solution settings
- Extraction settings
- Geometric (blended) mappingMappingIn geomatics or geospatial science and technology:Mapping usually refers to map-making and often used instead of cartography.Mapping term is also sometimes used for geospatial data collection but in fact it is not mapping because a map is created from some cartographic works In geomatics or...
capability for higher-order approximation of geometry- This is critical for detailed stress analysis and composite modeling
- Automatic meshing capability in 2D and 3D
- Advanced boundary layer meshing and crack insertion for fracture mechanicsFracture mechanicsFracture mechanics is the field of mechanics concerned with the study of the propagation of cracks in materials. It uses methods of analytical solid mechanics to calculate the driving force on a crack and those of experimental solid mechanics to characterize the material's resistance to fracture.In...
problems
- Advanced boundary layer meshing and crack insertion for fracture mechanics
- Handmeshing capability in 2D and 3D for improved discretizationDiscretizationIn mathematics, discretization concerns the process of transferring continuous models and equations into discrete counterparts. This process is usually carried out as a first step toward making them suitable for numerical evaluation and implementation on digital computers...
- H-discretization capability to automatically refine hand mesh
- Global-local capability, i.e. importing structural nodal loads from a global model into a local StressCheck detail model
- TLAP (Total Load At a Point) bearing and traction capability converts discrete point loads/moments into statically equivalent, smooth stress distributions
- Advanced laminated composite modeling capability
- Support for high aspect ratio elements (200:1 and larger) for representation of individual plies
- Automatic lamination capability for discretizationDiscretizationIn mathematics, discretization concerns the process of transferring continuous models and equations into discrete counterparts. This process is usually carried out as a first step toward making them suitable for numerical evaluation and implementation on digital computers...
of a simple mesh to a ply-by-ply or homogenized representation
- StandardizationStandardizationStandardization is the process of developing and implementing technical standards.The goals of standardization can be to help with independence of single suppliers , compatibility, interoperability, safety, repeatability, or quality....
via Handbook Solutions and Toolkit FEA- Each installation of StressCheck contains a library of pre-built HandbookHandbookA handbook is a type of reference work, or other collection of instructions, that is intended to provide ready reference .A handbook is sometimes referred to as a vade mecum or pocket reference that is intended to be carried at all times.Handbooks may deal with any topic, and are generally...
models to encompass a variety of commonly solved engineering problems. - Users may generate organization-specific Handbook solutions for standardization purposes.
- Each installation of StressCheck contains a library of pre-built Handbook
Finite Element Solver Features
- Linear ElasticityElasticity (physics)In physics, elasticity is the physical property of a material that returns to its original shape after the stress that made it deform or distort is removed. The relative amount of deformation is called the strain....
, including multi-body contact analysis of metallic and compositeComposite materialComposite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...
structures - Nonlinear ElasticityElasticity (physics)In physics, elasticity is the physical property of a material that returns to its original shape after the stress that made it deform or distort is removed. The relative amount of deformation is called the strain....
, including material (i.e. plasticityPlasticityPlasticity may refer to:Science* Plasticity , in physics and engineering, plasticity is the propensity of a material to undergo permanent deformation under load...
) and geometric nonlinearities - ModalModal analysis using FEMThe goal of modal analysis in structural mechanics is to determine the natural mode shapes and frequencies of an object or structure during free vibration. It is common to use the finite element method to perform this analysis because, like other calculations using the FEM, the object being...
/BucklingBucklingIn science, buckling is a mathematical instability, leading to a failure mode.Theoretically, buckling is caused by a bifurcation in the solution to the equations of static equilibrium...
analysis, including pre-stress buckling - Steady-State Conduction Heat TransferHeat transferHeat transfer is a discipline of thermal engineering that concerns the exchange of thermal energy from one physical system to another. Heat transfer is classified into various mechanisms, such as heat conduction, convection, thermal radiation, and phase-change transfer...
, including radiation and convection boundary conditions - 64-bit64-bit64-bit is a word size that defines certain classes of computer architecture, buses, memory and CPUs, and by extension the software that runs on them. 64-bit CPUs have existed in supercomputers since the 1970s and in RISC-based workstations and servers since the early 1990s...
Windows batch solver capability for solutions with extraordinary degrees of freedomDegrees of freedomDegrees of freedom can mean:* Degrees of freedom , independent displacements and/or rotations that specify the orientation of the body or system...
(DOF)
Post-Processing
- Inherent verificationVerificationThe word verification may refer to:* Verification and validation, in engineering or quality management systems, it is the act of reviewing, inspecting or testing, in order to establish and document that a product, service or system meets regulatory or technical standards.* Verification , in the...
capability for identifying and controlling discretizationDiscretizationIn mathematics, discretization concerns the process of transferring continuous models and equations into discrete counterparts. This process is usually carried out as a first step toward making them suitable for numerical evaluation and implementation on digital computers...
errors- Extract any FEA data of interest (i.e. stress, strainDeformation (mechanics)Deformation in continuum mechanics is the transformation of a body from a reference configuration to a current configuration. A configuration is a set containing the positions of all particles of the body...
, etc.) and convergenceConvergence-Mathematics:* Convergence , refers to the notion that some functions and sequences approach a limit under certain conditions* Convergence , the notion that a sequence of transformations come to the same conclusion, no matter what order they are performed in.-Natural sciences:*Convergence ,...
information for that data at any location in the model domain
- Extract any FEA data of interest (i.e. stress, strain
- Parameter and formula based post-processing
- Fracture mechanicsFracture mechanicsFracture mechanics is the field of mechanics concerned with the study of the propagation of cracks in materials. It uses methods of analytical solid mechanics to calculate the driving force on a crack and those of experimental solid mechanics to characterize the material's resistance to fracture.In...
extractions, including stress intensity factorsStress Intensity FactorThe stress intensity factor, K, is used in fracture mechanics to predict the stress state near the tip of a crack caused by a remote load or residual stresses. It is a theoretical construct usually applied to a homogeneous, linear elastic material and is useful for providing a failure criterion...
and J integralJ integralThe J-integral represents a way to calculate the strain energy release rate, or work per unit fracture surface area, in a material. The theoretical concept of J-integral was developed in 1967 by Cherepanov and in 1968 by Jim Rice independently, who showed that an energetic contour path integral ...
computation of separated energy release rates (i.e. J1, J2, and J3) - Ply by Ply extraction capability for laminated composite materials
Interfacing with External Tools
- COMComponent Object ModelComponent Object Model is a binary-interface standard for software componentry introduced by Microsoft in 1993. It is used to enable interprocess communication and dynamic object creation in a large range of programming languages...
API, allowing the ability to create or load models, solve them, and extract solution data using external programs such as AFGROWAFGROWAFGROW is the Air Force Growth crack life prediction software tool that allows users to analyze crack initiation, fatigue crack growth, fracture, and assess the life of metallic structures. AFGROW is one of the fastest, most efficient, and user-friendly crack life prediction tools available today...
, Microsoft ExcelMicrosoft ExcelMicrosoft Excel is a proprietary commercial spreadsheet application written and distributed by Microsoft for Microsoft Windows and Mac OS X. It features calculation, graphing tools, pivot tables, and a macro programming language called Visual Basic for Applications...
, MATLABMATLABMATLAB is a numerical computing environment and fourth-generation programming language. Developed by MathWorks, MATLAB allows matrix manipulations, plotting of functions and data, implementation of algorithms, creation of user interfaces, and interfacing with programs written in other languages,...
and Visual Basic .NETVisual Basic .NETVisual Basic .NET , is an object-oriented computer programming language that can be viewed as an evolution of the classic Visual Basic , which is implemented on the .NET Framework...
- Allows for the development of custom applications
- Optimization programs can interface with parametric modeling capability
- Automation scripts can be written to update and solve multiple models
Technology
StressCheck uses the p-version of the finite element methodFinite element method
The finite element method is a numerical technique for finding approximate solutions of partial differential equations as well as integral equations...
. The utilization of the p-version in finite element analysis was pioneered by Dr. Barna Szabó during his tenure at Washington University in St. Louis
Washington University in St. Louis
Washington University in St. Louis is a private research university located in suburban St. Louis, Missouri. Founded in 1853, and named for George Washington, the university has students and faculty from all fifty U.S. states and more than 110 nations...
. The p-version finite element method spans a space of high order polynomials by nodeless basis functions, chosen approximately orthogonal for numerical stability. Since not all interior basis functions need to be present, the p-version finite element method can create a space that that contains all polynomials up to a given degree with many fewer degrees of freedom.
In practice, the name p-version means that accuracy is increased by increasing the order of the approximating polynomials (thus, p) rather than decreasing the mesh size, h. Thus, to check for solution convergence by increasing the number of degrees of freedom in a given model, the shape function polynomial level is increased rather than remeshing with more elements, which is the standard FEA tool method. In StressCheck the maximum p-level is set to eight (8).
Application
StressCheck is used in a variety of industries, notably aerospaceAerospace
Aerospace comprises the atmosphere of Earth and surrounding space. Typically the term is used to refer to the industry that researches, designs, manufactures, operates, and maintains vehicles moving through air and space...
, and for a range of applications such as aircraft damage tolerance
Damage tolerance
Damage tolerance is a property of a structure relating to its ability to sustain defects safely until repair can be effected. The approach to engineering design to account for damage tolerance is based on the assumption that flaws can exist in any structure and such flaws propagate with usage...
assessment and analysis of composite materials for which high order elements are particularly useful.
See also
- hp-FEMHp-FEMhp-FEM is a general version of the finite element method , a numerical method for solving partial differential equations based on piecewise-polynomial approximations that employs elements of variable size and polynomial degree ...
- Spectral element methodSpectral element methodIn mathematics, the spectral element method is a high order finite element method.Introduced in a 1984 paper by A. T. Patera, the abstract begins: "A spectral element method that combines the generality of the finite element method with the accuracy of spectral techniques..."The spectral element...
- List of finite element software packages