Resources

• Methods for Modeling Bolts in the Bolted Joint

  Jerome Montgomery

  "Modeling bolts for three-dimensional finite element applications have, and still continue to raise questions. The limitations on model size sometimes make modeling of solid bolts impractical. Therefore, many analysts choose other methods to model bolts. Line elements with coupled nodes and line elements with spider beams are a couple of alternative approaches. This paper looks at a few methods for modeling pretension bolted joints using the finite element method (ANSYS 5.7). Pretension is modeled using ANSYS pretension elements (PRETS179) which can be used on solid or line element types. Surface-to-surface contact elements are used to account for varying contact distribution along flanges. Bolt head and nut behavior is modeled by, coupled nodes, beam elements, rigid body elements (RBE3), or solids. Bolt stud is modeled by solid elements, beam elements, pipe elements, or link elements. The choice of line elements versus solid elements is determined by the degree of complexity sought. The pros and cons of different simulations are also discussed."

• Micromachined Piezoelectric Ultrasonic Transducers Based On Parylene Diaphragm In Silicon Substrate

  Cheol-Hyun Han and Eun Sok Kim

  "This paper describes the techniques used in fabricating the transducers, their performance characteristics, and finite element analyses (FEA) with ANSYS 5.6. With ANSYS, we have calculated the stress and strain (under a static pressure load) and the dynamic mode shapes over a certain frequency range. Also, with appropriate piezoelectric matrices incorporated into the ANSYS batch model, a piezoelectric coupled-field analysis has been performed." (MEMS)

• Microsystem Design Using Simulator Coupling

  S. Wünsche, C. Clauß, P. Schwarz, F. Winkler

  "A methodology for simulating the performance of complex microsystems using simulator coupling is presented. The technique is based on the coupling of the FEM program ANSYS with the circuit and system simulator SABER."

• Modal Cyclic Symmetry Enhancements at 6.0 [PDF]

  Sheldon Imaoka (ANSYS, Inc.)

  "At ANSYS 6.0, the modal cyclic symmetry procedure has been significantly improved. New commands, CYCLIC and CYCOPT, replace the older CYCGEN and CYCSOL macros and provide more flexibility and ease-of-use."

• Modeling Approach for CVD-Diamond-based Mechanical Structures [PDF]

  P. Schmid, M. Adamschik, S. Ertl, P. Gluche, and E. Kohn

  Analysis of diamond-based MEMS devices (instead of silicon) with ANSYS.

• Modeling Diesel Engine Cylinder Head Gaskets using the Gasket Material Option of the SOLID185 Element

  Jonathan Raub

  "The modeling of diesel engine cylinder head gasket joints is complicated by the nonlinear response of the head gasket’s materials. Linearization of these material responses can lead to significant errors in the solution’s results. The 1-dimensional nonlinear approximation made by the Gasket material option of the SOLID185 element sufficiently captures the response of the nonlinear gasket materials while maintaining practical solution times for the large model sizes associated with multi-cylinder head gasket joint models. This paper will give an overview of the model building and assembly process used to create a head gasket joint model, describe the nonlinear nature of the materials used in the model, and present comparisons of the model’s results with experimental measurements."

  [STI: There is a gasket-specific material & element in 6.1, not available at the time of the writing]

• Modeling MEMS Resonant Devices Over a Broad Temperature Range [PDF]

  Russell DeAnna, Shuvo Roy, Christian A. Zorman, Mehran Mehregany

  (from ANSYS Solutions magazine, volume 1, #2) (MEMS)

• Modeling Of Aluminum Reduction Cells Using Finite Element Analysis Techniques

  Imad Tabsh, Marc Dupuis

  "This paper summarizes the authors' experience in using FEA to model Hall-Héroult reduction cells. FEA capabilities necessary to adequately simulate thermo-electric, electro-magnetic and stress fields within the cell are identified." (Used ANSYS 4.4A and 5.0)
  Available is an older, related paper on Thermo-Electric Coupled Field Analysis of Aluminum Reduction Cells Using the ANSYS Parametric Design Language.

• Modeling Viscous Behavior [ZIP]

  Sheldon Imaoka (ANSYS, Inc.)

  "Amorphous solids or solids at elevated temperatures may exhibit viscous behavior. It may be difficult for some users to determine how best to model such behavior. This memo hopes to describe some available options in ANSYS and to differentiate between viscoelastic and viscoplastic constitutive models."

• Modeling an Electrostatically Actuated MEMS Diaphragm Pump

  James Nabity

  The recent advent of microelectromechanical systems (MEMS) or micro-devices has generated excitement in many diverse fields. In the area of micro-fluidics liquid pumps are highly desirable for fluid transport and atomization. A recent and popular example of this is the inkjet, which self-aspirates ink from a reservoir and then transports it to a chamber for expulsion as a single droplet during the printing process. Extending this technology to other potential applications requires analytical and computational tools for design. Several computational software packages are commercially available, such as CoventorWareTM, FLUENTTM, and ANSYSTM [1-3], but each is difficult to use and to date only ANSYS has been able to solve this fully coupled multi-physics problem. Thus, simplified analytical models are attractive for preliminary design and analysis. This paper describes a quasi one-dimensional model developed for the design and analysis of an electrostatically actuated diaphragm pump. The attributes and assumptions of this model will be presented. Finally, performance results obtained for a MEMS diaphragm pump will be compared to ANSYS three-dimensional time-accurate results.

• Modeling of the Piezoelectric Micropump for Improving the Working Parameters [PDF]

  Oana Tatiana Nedelcu, Victor Moagar-Poladian

  A piezo micropump. Used ANSYS for analysis of deflection of pump. (MEMS)

• Modeling preloaded bolts [PDF]

  Sheldon Imaoka (ANSYS, Inc.)

  Modeling preload in bolts via contact offset, thermal contraction, or the new pretension elements PRETS179.
  PRELOAD1, PRELOAD2, and PRELOAD3 input files

• Modelling and Experimental Investigations on Degradation of Microcomponents in Power Cycling

  M. Thoben, W. Staiger, J. Wilde

  "Thermomechanical damage is one of the principal failure causes of microcomponents and microsystems. Often the basic defect mechanisms are crack initiation and subsequent crack propagation in interfaces or materials. The fatigue behavior of microcomponents can in many cases be described by the Manson-Coffin-Formula. This model is well-suited for comparison of different designs relative to each other but it will fail when a realistic lifetime prognosis is expected. Therefore we worked out a concept which is based on the computation of the strain range distribution in the interconnection by finite elements simulations and subsequent calculation of the cyclic crack propagation rate. Using this method in combination with calibration measurements it is possible to predict the lifetime of electronic assemblies with significantly improved precision compared to the Low-Cycle-Fatigue approaches."

• Multi-Criteria Shape Optimization of a Funnel in Cathode Ray Tubes Using Response Surface Model

  Tae Hee Lee, Kwangki Lee, Kwang Soon Lee

  "The ultimate goal of simulation that represents the behaviour of structures is to optimize their response performances within the specific requirements and needs with respect to the design variables. The first step of the design of cathode ray tubes is to design the glass geometry, called funnel geometry, to endure the vacuum stress because it is a main structure of cathode ray tubes. In order to create 3-dimensional funnel geometry in the cathode ray tubes, higher order response surface model is used instead of NURBS (non-uniform rational B-splines) or Bezier curve because it is more robust for understanding the geometry change in finite element analysis. By combining finite element analysis, response surface model and sequential quadratic programming within the process integration framework, the shape optimization of a funnel is successfully performed and the maximum stress is reduced to almost half of the current one."

• Multiframe Restarts [PDF]

  Sean Harvey (CSI)

  Memo covering the multiframe restart capability (RESCON) in ANSYS.
  Accompanying input file

• Neighborhood-based Element Sizing Control for Finite Element Surface Meshing [PDF]

  Steven Owen, and Sunil Saigal

  "A method is presented for controlling element sizes on the interior of areas during surface meshing. A Delaunay background mesh is defined over which a neighborhood based interpolation scheme is used to interpolate element sizes."

• Nested macros, local parameters, trailing underscores

  Martin Herrenbruck (Technische Universität München)

  "A macro file is a file which contains Ansys commands. If you save your macro in your working directory or in the macro directory (see /PSEARCH command) you just enter the macro name in the command line and all these commands will be executed. You can even nest macros: from your main file you call e.g. zzmacro1 which again calls zzmacro2. The only problem is that a macro could change - and you would probably not notice that - the value of a parameter you are using in your main input file. This will be the case if the same parameter name is used accidentally in both the macro and your main input. Let's see how one can avoid these nasty errors - just click on the link!"

• Non-Linear Elastic Properties of the Lingual and Facial Tissues Assessed by Indentation Technique: Application to the Biomechanics of Speech Production

  J.M. Gerard, J. Ohayon, V. Luboz, P. Perrier, Y. Paya

  "This paper aims at characterizing the mechanical behavior of two human anatomical structures, namely the tongue and the cheek. For this, an indentation experiment was provided, by measuring the mechanical response of tongue and cheek tissues removed from the fresh cadaver of a 74 year old woman. Non-linear relationships were observed between the force applied to the tissues and the corresponding displacements. To infer the mechanical constitutive laws from these measurements, a finite element (FE) analysis was provided. This analysis aimed at simulating the indentation experiment. An optimization process was used to determine the FE constitutive laws that provided the non-linear force/displacements observed during the indentation experiments. The tongue constitutive law was used for simulations provided by a 3D FE biomechanical model of the human tongue. This dynamical model was designed to study speech production. Given a set of tongue muscular commands, which levels correspond to the force classically measured during speech production, the FE model successfully simulated the main tongue movements observed during speech data."
  [ANSYS Nonlinear, version 5.7]

• Non-linear Finite Element Modeling of the Titanium Briquettes Hot Extrusion Process

  Alexey I. Borovkov, Denis V. Shevchenko

  "In this paper the mathematical model is developed to perform mathematical simulation of the hot extrusion process. The model makes it possible to observe the influence of various system parameters on the extrusion process. All researches were carried out with the use of the ANSYS 5.6 RFS FE-software system. During the research the modeling and analysis of various events that can be observed (material dead zone appearing, capsule crimping, capsule damage etc.) was successfully carried out. The mathematical model was created on the basis of contact thermo-mechanics relations with physical and geometrical non-linearities."

• Nonlinear Contact Analysis Techniques Using ANSYS

  (ANSYS, Inc.)

  Presentation on various aspects of 17x contact technology (part of the "Advanced Analysis with ANSYS" seminar during the 2002 User's Conference).

• Nonlinear Mechanics of Suspension Beams for a Micromachined Gyroscope

  W. O. Davis and A. P. Pisano

  "We present a method for the calculation of the coefficients of cubic stiffening for tether-suspended micromachined systems. The analysis is based on a nonlinear rod theory, and enables the prediction of the maximum achievable motion amplitude prior to the onset of nonlinear behavior. The analysis is applied in detail to a microgyroscope. Comparisons with a finite element model and experimental data are used to validate the analysis, and issues pertaining to the optimal design of the gyroscope's suspension are investigated." (MEMS)

• Nonlinear Models of Reinforced and Post-tensioned Concrete Beams

  P. Fanning

  "Commercial finite element software generally includes dedicated numerical models for the nonlinear response of concrete under loading. These models usually include a smeared crack analogy to account for the relatively poor tensile strength of concrete, a plasticity algorithm to facilitate concrete crushing in compression regions and a method of specifying the amount, the distribution and the orientation of any internal reinforcement. The numerical model adopted by ANSYS is discussed in this paper. Appropriate numerical modelling strategies are recommended and comparisons with experimental load-deflection responses are discussed for ordinary reinforced concrete beams and post-tensioned concrete T-beams." (Concrete SOLID65)

• Nonlinear Submodeling [ZIP]

  Sheldon Imaoka (ANSYS, Inc.)

  "Submodeling is often used to efficiently obtain solutions at local areas. Although submodeling may be commonly thought of as being applicable to linear static structural solutions, it can also be applied to nonlinear and transient analyses, as well as other disciplines. This memo hopes to cover the specific case of nonlinear static structural submodeling."
  (Week 14, week of 01/14/02.)

• Nonlinear monitoring [PDF]

  Sheldon Imaoka (ANSYS, Inc.)

  Memo covering the benefits of the jobname.mntr file and the MONITOR command in nonlinear analyses.

• Novel Horn Designs for Ultrasonic/Sonic Cleaning Welding, Soldering, Cutting and Drilling

  S. Sherrit, S.A. Askins, M. Gradziol, B.P. Dolgin, X. Bao, Z. Chang, and Y. Bar-Cohen

  "In this paper we will present a variety of novel horn designs, which overcome some of the limitations discussed above. One particular design that has been found to overcome these limitations is the folded horn. In this design the horn elements are folded which reduce the overall length of the resonator (physical length) but maintain or increase the acoustic length. In addition initial experiments indicate that the tip displacement can be further adjusted by phasing the bending displacements and the extensional displacements. The experimental results for a variety of these and other novel horn designs will be presented and compared to the results predicted by theory."
  [ANSYS Piezoelectric, version unknown]

• Numerial Implementation of Multiaxial High-Cycle Fatigue Criterion to Structural Optimization

  Miroslaw Mrzyglód, Andrzej P. Zielinski

  "Modern multiaxial high-cycle fatigue criteria were investigated with respect to their application in structural optimization procedures coupled with finite element codes. As a result of tests carried out for several fatigue criteria, the Dang Van hypothesis was used for the detailed numerical study. A way of respective adapting the high-cycle load history was also suggested. The complete algorithm of the fatigue optimization was illustrated by applying the proposed procedures to vehicle parts which are subject to high-cycle loadings. The finite element code ANSYS was used in the structural modeling."

  [ANSYS Structural, version 8.1]

• Numerical And Analytical Modeling Of The Piezoelectric Transformer And Experimental Verification [PDF]

  S. Hallaert , E. Sarraute and B. Le Pioufle

  Use of ANSYS for modal analysis of miniature piezo transformer. (MEMS)

• Numerical Modeling for Systematization of Line Heating Process

  Jong-Gye Shin, Won-Don Kim, and Jang-Hyun Lee

  "In this paper, we first propose a conceptual configuration for ship production system of plate forming. It is necessary to integrate lofting and plate forming activities for minimum thermal energy in line heating process. The modeling of heating torch, water cooling, and plate to be formed is proposed for the finite element analysis after the mechanics of line heating is studied. A three-dimensional 8-node solid elements of ANSYS were chosen for analysis."
  (Thermal-Stress)

• Numerical Simulations of Flat-walled Diffuser Elements for Valveless Micropumps [PDF]

  Anders Olsson, Goran Stemme, and Erik Stemme

  Use of ANSYS/Flotran for analysis of micropump. (MEMS)

• Off-Axis Loads Cause Failure of the Distal Radius at Lower Magnitudes than Axial Loads: A Finite Element Analysis

  Karen L. Troy and Mark D. Grabiner

  "Distal radius fractures are among the most common fall-related injuries in older women. Numerous studies have quantified upper extremity fall biomechanics with the goal of identifying possible interventions to reduce the peak force on the wrists, thereby reducing the number of fractures. Fracture initiation depends both on the force applied to the bone and upon the strength of the bone itself; thus, poor bone quality has been implicated as a factor in distal radius fractures. Generally, an intervention to improve bone quality (such as antiresorptive therapy) is considered successful if bone mineral density (BMD) can be increased by 2-4%.
  Cadaver and finite element studies have previously quantified the force required to cause a distal radius fracture. To date, however, only simple axial loads on the radius have been considered. Because most falls onto the hands result in off-axis loads, we considered the possibility that a combination of loading modes would significantly influence the fracture strength of the distal radius. Here, we used a validated finite element model of the distal radius, scaphoid, and lunate, to explore the effects of loading direction and changes in BMD on predicted fracture strength."
  [ANSYS Structural, version 10.0]

• On Stress Analysis For a Hyperelastic Material [PDF]

  Xiao-Yan Gong and Riyand Moe

  Paper using ANSYS 5.5 for characterizing hyperelastic materials with Mooney-Rivlin

• Optimal Design of Computer Experiments for the Generation of Microsystem Macromodels Using IMSET and Non-Parametric Fitting

  Selden B. Crary, Peter Cousseau, David Armstrong, David M. Woodcock, Olivier Dubochet, Philippe Lerc

  "We present a new and unique software program, IMSET, capable of finding optimal designs for computer experiments. A finite-element simulation of a micro-machined flow sensor was used to illustrate macromodel generation and to compare the quality of the IMSET design with other approaches."

• Optimization of a Circular Piezoelectric Bimorph for a Micropump Driver

  Christopher J. Morris and Fred K. Forster

  "Piezoelectric bimorph actuation has been successfully used in numerous types of microdevices, most notably micropumps. However, even for the simple case of circular geometry, analytical treatments are severely limited. This study utilized the finite-element method to optimize the deflection of a circular bimorph consisting of a single piezoelectric actuator, bonding material and elastic plate of finite dimensions. Optimum actuator dimensions were determined for given plate dimensions, actuator-to-plate stiffness ratio and bonding layer thickness." (PLANE13)

• Optimizing Board-level Reliability of an Underfilled, Stacked Chip Scale Package

  Zane E. Johnson, Nathan R. Schneck

  "Previously benchmarked finite-element (FE) models of a stacked chip scale package (CSP) are used to identify optimum underfill material properties under drop-impact and accelerated temperature cycling (ATC) stress conditions. The simulation sets indicate that an underfill having a modulus of 2–6 GPa and CTE of 25 ppm/K maximizes drop life and does no harm to ATC performance for both Sn63Pb37 and SAC305 solder joints. The methodology described can be applied to other package styles, material sets, and stress conditions."

• Optimum Design of a Ceramic Tensile Creep Specimen Using a Finite Element Method

  Z. Wang, C. K. Chiang, and T. J. Chuang

  "An optimization procedure for designing a ceramic tensile creep specimen to minimize stress concentration is carried out using a finite element method."
  (Optimization, Creep, Contact)

• Overview of Reliability Models and Data Needs

  Ahmer Syed

  "Workshop on Modeling and Data Needs for Lead-Free Solders" (Amkor Presentation) Note that FEA pictures in presentation are ANSYS plots - Darveaux's data is based on Anand's Model (TB,ANAND), although ANSYS also allows for use of common creep laws such as hyperbolic sine and power law.

• PDF file summarizing beta contact features at 5.6.1 [PDF]

  Sheldon Imaoka (CSI)

  Presentation on the thermal contact and fluid pressure capabilities of the surface-to-surface contact elements. This was written when these capabilities were beta at 5.6. Thermal capabilites are documented at 5.7.
  Accompanying thermal contact example and fluid pressure example

• PDS and Nonlinear Runs [ZIP]

  Sheldon Imaoka (ANSYS, Inc.)

  "The Probabilistic Design System (PDS) of ANSYS provides a very powerful tool in understanding the effect of uncertainties in one’s design. The details of PDS are covered in the online help, so this memo will discuss the specific case of setting up serial and parallel PDS runs as well as performing nonlinear analyses with PDS."

• POW2MAT.zip

  Carl Olsard (noiseboard.com)

  "This is a simple program written in Turbo pascal which I find very useful for converting the output from ANSYS (prvar, prnsol, etc) into columns, while removing the headers at the start and between the page listings. The program is used at a DOS prompt and one types in: pow2mat col filein fileout , where col are the number of columns in the output, filein MUST have an extension .val and fileout WILL have an extension .txt. You do NOT type in the extensions, they are default. For example, you would type pow2mat 7 nodelist nodelist which would extract 7 columns from the file nodelist.val and write a stripped file called nodelist.txt . If you have several files to convert, you can use the DOS FOR command as follows:
  FOR %I IN (*.val) DO pow2mat 3 %~nI %~nI"

• PRESSURE_MAC.zip

  Hursha Narayan (Robert Bosch Corporation)

  "I have written a macro that calculates the total force along the three axes from applied pressure. I find this macro to be useful just to make sure that the pressure I'm applying on a curved surface is accurate and also it gives a feel for the mesh discretization where the pressure is applied. The user has to basically identify the elements with a particular magnitude of pressure and save the list file (SFELIS.lis). The macro does everything else automatically. The downside to the macro is:

  1. Right now it only handles 10 node tet elements.
  2. The pressure has to be uniform
     The user will have to modify some of the fields in the macro as well as the c-shell file prescalc."