MAJOR FEATURE ENHANCEMENTS
The latest version of CAEfatigue VIBRATION contains major feature improvements including
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ADDITIONAL FEATURES AND CAPABILITIES
CAEFATIGUE VIBRATION (CFV) IS AVAILABLE IN TWO DIFFERENT MODULES
CAEfatigue VIBRATION (CFV) is a random response and vibration fatigue solver. It works with mixed random and deterministic loading to provide fatigue life and damage predictions, as well as several forms of response statistics. It is exceptionally fast, easy-to-use and capable of handling very large models.
The software is sold in two different modules.
Random Response plus Full Fatigue for Single Input
The CFV-BASE module is designed to provide the user with both the random response results and the fatigue results from a structure undergoing loading input from a single random PSD with or without additional loading from deterministic inputs and mean offsets. Response outputs includes mean stress, RMS stress or strain, mean stress plus RMS stress or strain, moments, zero crossings, peaks per second and irregularity factor. Fatigue results including damage, life and margin of safety from a single random input.
The loading inputs needed for CFV can come from Optistruct, Nastran, Ansys or Abaqus generated from (virtually) any size model. Examples of inputs are simultaneous wide band and narrow band inputs, wide band random and swept sine inputs, wide band random and deterministic inputs, wide band and swept narrow band inputs, swept narrow band or swept sine wave.
Random Response plus Full Fatigue for Multiple Input
The CFV-MULTI module offers all the input / output options from CFV-BASE plus the ability to use multiple random input PSDs (and cross PSDs) with mean offsets i.e., data from a test rig with multiple events and multiple channels per event plus a mean offset. This module offers random response and S-N or E-N fatigue results generated from the multiple simultaneous correlated load inputs, with any number of DOF’s, inputs, events and frequencies. Coupled with CAEfatigue RANDOM, CFV-MULTI becomes a powerful tool for understanding output results for displacement, velocity, acceleration, force, stress, strain and fatigue (damage / life).
A clean, modern graphical user interface for pre and post processing.Response analysis, fatigue analysis and the use of a graphical user interface have traditionally suffered from a lack of democratisation; that is to say, only expert users have been fully capably of using the technology. CFG aims to change this in two ways.
First, a control file setup Wizard is provided to help the user create the input control file and many variables are either used in default mode or are automatically calculated based on an understanding of the system being analysed.
Second, a comprehensive Technology Transfer package is included within the software which is directly accessible from within the software GUI. More than 100 hours of video training material from beginner level to advanced level is included along with more than 100 relevant Test Problems to aid the User in understanding the technology. The CFG software tool provide the simplicity desired by the engineer and designer along with the functionality and visual graphics found in many of the post processing packages available today.
A Frequency Domain based Spot and Seam Weld Tool.CAEfatigue Limited has created an industry first! Using our latest software module, CF_JOINTS, we now provide the ability to conduct a full Spot Weld and Seam Weld analysis in the Frequency Domain. This capability will allow a full automotive vehicle analysis, that includes spot and seam welds to be conducted with CFV all at the same time.
A Time Domain based fatigue solver.CAEfatigue Limited have implemented a step change in the way frequency based analysis is performed for both fatigue and random response analysis. The CFT* module is intended to provide the same step change improvement – but this time for conventialnal modal superposition (static) and modal participation factor (dynamic transient) types of analysis. The CFT tool uses state of the art software development tools and algorithms to deliver a fatigue solver with superior speed and accuracy. Coupling CFT with CFV and our other software products provides our customers with a complete time and frequency domain analysis package that surpasses the performance and accuracy needs of our uses.
*CFT is currently in development. Please contact CAEfatigue Limited for further information.
An automated way to convert a time history into a power spectral density (PSD).Historical loads conditioning procedures involve a series of user options that are hard for a typical engineer or designer to implement. Some of these have now been automated in the CFC approach. Both window length (FFT buffer size), window overlap, and initial deletion of non-relevant parts of the signal can all be done automatically. The CFC tool provides a way to correctly eliminate sections of the time history that do not contribute to the damage. Conditioning is vital to ensure the damage from the time history is correctly transferred to the Power Spectral Density (PSD). The CFC tool also converts multi-input time histories to a PSD matrix that organizes, labels and tracks the PSDs to correctly account for cross correlation effects. An option also exists within CFC to switch on or off, the correlation terms to evaluate the influence on damage. The connections with solver subcase ID’s are automatically dealt with so the user does not have to take extra time managing the data.
For those who require advanced random response statistics and collision detection.For many automotive and aerospace systems it is required to calculate both the durability and to rule out the possibility of collision of individual components during severe base shake vibration conditions. Advanced frequency domain methods now exist to enable the durability assessment and response to be assessed in the frequency domain. With the CFR module it is possible to output displacement and/or velocity and/or acceleration and/or force rms levels and Power Spectral Density (PSD) plots for both absolute and relative responses. In addition, a residual sum of the squares (RSS) is calculated to take into account any off axis response. New post processing options allow the relative response from any node to be compared against the actual distance to all and any nearby nodes in order to check for the probability of collisions (i.e. RATTLE) between adjacent components. The response maximum is determined using either a ratio of the rms (e.g. 3.0*rms) from a corresponding level of probability on a Gaussian or Rayleigh distribution, or by using a method which takes into account the number of cycles of response. CFR (coupled with CFV) is an excellent tool to predict structural response under complicated loading conditions found in many engineering applications throughout a wide variety of industries.
Replace a complex test rig time history with a surrogate PSD that gives you the same fatigue damage.The specification of loads for durability is a very important topic. Ideally, any loads used in an analysis or in a laboratory based test procedure, should be as close as possible to the Customers use of the product. In practice, the nearest scenario that can be achieved is to measure multi events and multi input loads (with correlation) from prototype vehicles (test tracks) and then replay these in the laboratory or analysis environment. For analysis, this is feasible and is a commonly adopted method although it does not easily deal with the topic of test acceleration. For laboratory based simulation, especially of parts or subsystems, there is a need (usually because of available test equipment) to simplify the loads down to single input load one at a time (e.g, X, then Y, then Z), which this poses significant challenges. Two common approaches are currently used. First, an enveloping procedure can be applied to the loads where the multiple loads are combined into a single smoothed profile. A classical application of this procedure involves no knowledge of the structural system so there is no assurance that the enveloped loads will cause the same damage values or distribution. Second, is to use the concept of a Fatigue Damage Spectrum (FDS) where a simplified loading is created which does the same damage on a hypothetical 1 DOF system (where the resonance is moved through the loading). Again, this takes no account of the actual structural system or systems. The CFS* module provides a NEW approach, which is a variation of the FDS approach but using the actual system properties. The CFS tool provides a way to transform a complicated multi-input and multi-event time history loading into a simplified “SURROGATE LOAD” that will provide the SAME damage output for the system as the complex test time history.
*CFS is currently under development and is scheduled to be released in Q2 2019 or sooner.