Pdf test analysis verification using open software. Coordinates in 3d coordinate systems describe the 3d positioning and origin of the system. It thus becomes possible to provide improved modal assurance criterion. Taking the classical modal assurance criterion mac, the need to. Coordinate systems are used to place elements in relation to each other. Data is represented using either a geographic coordinate system latitudelongitude or a projected coordinate system xy. Some of the other assurance criteria that will be discussed include the coordinate modal assurance criterion comac, the frequency response assurance criterion. Choose a web site to get translated content where available and see local events and offers.
Latitude and longitude specify the position of a point on the surface of a planet. The modal assurance criterion mac is the most widely used criterion for vector correlation mainly because of its simplicity. Suppose that the mode can fully be activated, then the generalized coordinate, q, of the mode of vibration represents the. See kinematics and machine motion state and how simscape multibody software works. Motion modeling and coordinate systems perform array and target trajectory modeling, coordinate transformations, and compute doppler shift the phased array system toolbox lets you model the motion of radars, sonars, targets, jammers, or interference sources using the phased. Comac coordinate modal assurance criterion copmeac coordinate pseudo modal energy assurance criterion cpu computer process unit.
The block computes the initial distance dt0 between the coordinate systems when the machine is in its home configuration, the original configuration of the machines bodies before the simulation imposes initial conditions and implements joint assembly. Modal assurance criterion one of the most popular tools for the quantitative comparison of modal vectors is the modal assurance criterion mac. It was found that the new modal mode assurance criterion guaranteed the completeness and. Timedependent distance between two body coordinate systems. Furthermore, genetic algorithms are introduced and applied to finiteelementmodel updating. Easymod, as for easy modal analysis after 30 years of development, experimental modal analysis is now established as a fundamental technique for understanding the vibration behaviour of structures. Model calibration of a vehicle tailgate using frequency. This function is to compute the modal assurance criterion mac between mode shapes. Below the majors benefits are listed along with a listing of all available techniques of the different versions of artemis modal. I want to visualize 2d coordinate systems in matlab, given the equations of the transformations. How can i compute the modal assurance criterion of experimental.
Coordinates in pixel and spatial coordinate systems relate to locations in an image. For this reason, a feature tailored so as to be well correlated to the expected differences between the undamaged and damaged flexibility matrices, such as the recently proposed flexibility proportional coordinate modal assurance criterion fpcomac, is ideally suited to be exploited as damage sensitive feature. The help system is web based, so maximum performance is obtained by having an. Modal analysis of structures consists of three distinct steps. All of novel optimal sensor placement processes were done through femmacttfd code modeled and developed in matlab by authors of this article. Technical specifications for the artemis modal 5 last update. Application of the craigbampton model order reduction. A graphical method of comparison was found for simple structures, which considers the spatial distribution of the entire frequency response spectrum. The modal assurance criterion is a statistical indicator that is. Sensor location in concrete slabs with various layout of. Modal assurance criterion the modal assurance criterion analysis mac analysis is used to determine the similarity of two mode shapes.
Defines degrees of freedom in the reduced eigendata set eset used for modal assurance criterion mac analysis. Impacts of the weight coefficient and modal assurance criterion of. This matlab code implements the fdd technique for outputonly modal analysis. Lieven and erwins proposed a mode shape based damage indicator named the coordinate modal assurance criterion comac. Modal assurance criterion mac file exchange matlab.
Techniques for synthesizing frfs from analytical models. Modal assurance criterion mac siemens plm community. On the classification of normalized natural frequencies. Robotics system toolbox provides functions for transforming coordinates and units into the format required for your applications. Taking the classical modal assurance criterion mac, the need to diagnose. Lets say you have a figure, and that figure contains an axes object with handle haxes. Point compliances represented by a color scale are. We provide functions to compute modal assurance criteria mac and orthogonality, generate rigid body mode shapes from supplied finite element model geometry, generate a modal substructure from mode shapes, compute normal, complex, and multivariate mode indicator functions, and synthesize frequency response functions frf from real normal modes. All treated theory is implemented in matlab code and these scripts are extensively explained. Spatial correlation of mode shapes, the coordinate modal assurance criterion.
Modal assurance criterion mac file exchange matlab central. Damage assessment in reinforced concrete beams using. Experimental modal analysis by dr mohit law, iit kanpur. Excel macro for mode shapes orthogonalization youtube. Up to six unique digits may be placed in the field with no embedded blanks. Phillips university of cincinnati structural dynamics research lab ucsdrl, cincinnati, ohio, usa abstract. For more information on the spatial coordinate system, see spatial coordinates image processing toolbox. Macec is a powerful tool that deals with every step in the modal analysis procedure, except for the data collection. Using the function ginput would allow you to select points within the axes. Using the finite element method presented in the previous section and the matlab code, the damage is supposed to be, each time, in an. Spatial correlation of modeshapes, the coordinate modal assurance criterion comac, 1995. This function calculates the modal assurance criterion matrix. Find, read and cite all the research you need on researchgate. In a camerabased coordinate system, the points are defined relative to the center of the camera.
Citeseerx scientific documents that cite the following paper. How can i compute the modal assurance criterion of experimental mode and fe mode shape. Nonlinear aeroelastic scaling studies of high aspectratio wings. This study presents matlab tools developed for numerical process of all steps of dynamic vibration test of structures. The coordinate modal assurance criterion comac is calculated using the following approach, once the mode pairs have been identified with mac or some other approach. Techniques for synthesizing frfs from analytical models hasan g.
To increase speed, it makes use of mathematical libraries from intel. Comac coordinate modal assurance criterion daq data acquisition efi effective independence. Artemis modal is a powerful and versatile tool designed for the oma, ema, ods and shm analysis. Matlab is a unique system that can be used for structural and earthquake engineering problems. Damage assessment in reinforced concrete beams using eigenfrequencies and mode shape derivatives. Introduction high aspectratio wings have been studied with the objective of improving aircraft performance. Coordinate modal assurance criteria and coordinate pseudo modal energycriteria. Some of the other assurance criteria that will be discussed include the coordinate modal assurance criterion comac, the frequency. Note that the above formulation assumes that there is a match for every modal vector in the two sets and the modal vectors are renumbered accordingly so that the matching modal vectors have the same subscript. Use the coordinate system blocks to standardize units across your model, transform spatial representations and coordinate systems, describe the behavior of three and sixdegreesofmotion bodies, and perform common aerospace math operations. Ecomac enhanced coordinate modal assurance criterion. Field definition type default gi grid point identification numbers. Does comsol calculate mac of mode shapes obtained by fea and mode shapes derived from experimental modal analysis ema.
To access locations in images, the image processing toolbox uses several different image coordinate systems as conventions for representing images as arrays. To get an equivalent set of points from get0, pointerlocation, which gives coordinates in relation to the screen, you have to account for the figure position, axes position. Apart from this, it has been developed a graphic interface in matlab that implement the modal analysis. Spatial correlation of modeshapes, the coordinate modal assurance criterion. These masks were shown to successfully decouple the angular components of the sources direction, improving the average criterion value by up to 83% and limiting the directional uncertainty to the order of the physical systems angular resolution. In the internal development of the modal assurance criterion at the university of cincinnati, structural dynamics research lab ucsdrl, a little modal assurance criterion little mac 1, a big modal assurance criterion big mac and a multiple modal assurance criterion multimac3 were formulated as part of the original development. Coordinate systems are an important part of aerospace systems. In this article we present a pedagogical example of using experimental modal analysis to verify and calibrate a finite. Criterion behaviour which focuses only on the eigen values and eigen vectors. I want to generate images which look something like this. Superscript mc refers to measured coordinate l superscript uc refers to unmeasured coordinate abbreviations cdlv comac dem dlv dofs eom fe fem frf mac mdof rfrf serep plate9 plate28 cumulative damage location vector coordinate modal assurance criterion dynamic expansion method damage location vector degrees of freedom. Jan 16, 2020 multiobjective optimization based on the coordinate modal assurance criterion comac and cost considerations was considered in the optimization processes. Multiple damage detection and localization in beamlike.
Taking the classical modal assurance criterion mac, the need to diagnose sensors contributing to poor correlation was identi. Xmodal experimental modal analysis software structual. However, the convergence rate becomes slower for the case of multiple damages compared to the case of single damage. Heres an example of how you can do this conversion. All of the analysis, discretization and optimization process was designed and developed as a novel approach in matlab by the author under the name femscomac fem analysis of slab. Coordinate transformations and trajectories matlab. The development of the mac was modeled after the development of the ordinary coherence calculation associated with computation of the frequency response function. Comparative study of model correlation methods with application to. The modified type of modal assurance criterion values can be achieved from modal assurance criterion with the exact seismic displacement.
Some of the other assurance criteria that will be dis cussed include the coordinate modal assurance criterion. When you reconstruct a 3d scene, you can define the resulting 3d points in one of two coordinate systems. Abstract the craigbampton model order reduction cbmor method based on the rayleighritz approach was applied in a previous work to simulate dynamic behavior of a composite structure cfrp using the modal assurance criteria mac and cross orthogonality xor to validate the correlation. Additionally, this program could be reused for different methods just with few adjustments. This could be done in matlab, scilab, python or even excel. The results show that the proposed combination of coordinate modal assurance criterion and firefly algorithm or genetic algorithm can be easily used to identify multiple local structural damages in complex structures. Considering the shortcomings of the modal assurance criterion in the observation station selection and optimization algorithm for the structural modal testing experiment, this paper proposed a new criterion on the basis of the rule that the vibration mode is weightedorthogonal to the mass. Improved modal assurance criterion using a quantification of. Modified modal domain analysis mmda, a reduced order modeling technique, is applied to a geometrically mistuned integrally bladed rotor to obtain its natural frequencies, mode shapes, and forced response. The application of modal analysis underpins the theoretical and practical modelling of structural dynamic performance. Use the coordinate system functions to standardize units across your model, transform spatial representations and coordinate systems, describe the behavior of three and sixdegreesofmotion bodies, and perform common aerospace math operations. The mac and comac factors may be mentioned in this category. On the classification of normalized natural frequencies for damage detection in cantilever beam. They considered both transvers and rotational mode shapes of a damaged structure and undamaged one.
Mode shapes in comsol experted to matlab where processes experimental data. The modal assurance criterion twenty years of use and abuse. Modes matching, coordinate modal assurance criterion, composite materials, primary quantities. Modal assurance criterion mac and coordinate modal assurance criterion comac based on the basic modal parameters of structures such as natural frequencies, damping ratios, and mode shapes, some coefficients derived from these parameters can be useful for damage detection. Modal assurance criterion file exchange matlab central. How can i compute the modal assurance criterion of. Citeseerx document details isaac councill, lee giles, pradeep teregowda. Frequencyresponse functions for modal analysis matlab modalfrf. Orthogonality is verified using modal assurance criterion. Based on your location, we recommend that you select. Modal assurance criterion mac this function is to compute the modal assurance criterion mac between mode shapes. Correlation topics 122901 1 faculty server contact.
Matlab for all steps of dynamic vibration test of structures. Coordinate transformation yields statespace models with different matrices but identical dynamics. Improved modal assurance criterion using a quantification. How to assign a new coordinate system different than the global coordinates x,y for example, i need the new coordinate system to be a sine wave i drew on matlab, is there a function or a way to draw another sine function on the initial one.
The modal assurance criterion is useful for comparing test and simulation mode shapes. State coordinate transformation can be useful for achieving minimal realizations of statespace models, or for converting canonical forms for analysis and control design. The output, frf, is an h 1 estimate computed using welchs method with window to window the signals. Download citation the modal assurance criterion twenty years of use and. Orthogonalizing a set of mode shapes using the grammschmidt algorithm. This function is to compute and plot modal assurance criterion mac matrix between identified mode shapes. Teaching the topic of structural dynamics in any engineering field is a true challenge due to the wide span of the underlying subjects like mathematics, mechanics both rigidbody and continuum mechanics, numerical analysis, random data analysis and physical understanding. Then, you can download the excel files and work with your own data. Finiteelementmodel updating using computional intelligence. You can also generate trajectories using polynomial equations, bsplines, rotation matrices, homogeneous. Coordinate reference systems provide a framework for defining realworld locations. Different coordinate modal assurance criteria are applied to complement and verify the. On the classification of normalized natural frequencies for.
As described in images in matlab, matlab stores most images as twodimensional arrays i. Research article a new optimal sensor placement strategy. The universal files produced by the cadax system are imported to matlab software in order to calculate the strain energy distribution and the flexibility matrices of the beams. To learn more about the different coordinate systems, see coordinate transformations in robotics. Multiple damage detection and localization in beamlike and. Pdf improved modal assurance criterion using a quantification of. Modal correlation of test and analytical data is an. Sep 23, 2015 this function is to compute and plot modal assurance criterion mac matrix between identified mode shapes. Use the coordinate system functions to standardize units across your model, transform spatial representations and coordinate systems, describe the behavior of three and sixdegreesofmotion bodies. The wingtip of these wings has less area, which causes less vortex induced downwash, leading to less induced drag.
Integer 0 required ci component number of global coordinate. To find the model order that gives the best tradeoff between accuracy and complexity, set orders to 1. Model calibration of a vehicle tailgate using frequency response functions. The modal assurance criterion mac introduced in 23. Coverage intensity of optimal sensors for common, isolated. The coordinate modal assurance criterion comac is cal. Impacts of the weight coefficient and modal assurance. Damage detection using flexibility proportional coordinate. The modal assurance criterion twenty years of use and.
They are defined as angles between the point, the equator, and the axis of rotation. To access locations in images, the image processing toolbox uses several different image coordinate systems as. X modal iii is an experimental modal analysis research software package that the university of cincinnati, structural dynamics research lab ucsdrl has, and continues to, develop in conjunction with a group of sponsoring companies and the ucsdrl research software consortium. Spatial correlation of mode shapes, the coordinate modal. Fault identification using neural networks and vibration data. Modal analysis on an exhaust manifold to define a catalyst fe. Modified modal domain analysis of a bladed rotor using. Multiobjective optimization based on the coordinate modal assurance criterion comac and cost considerations was considered in the optimization processes. A new flexibility based damage index for damage detection.
The particleswarm optimization method is also introduced and applied for finiteelementmodel updating and the results are compared to those obtained from. In the internal development of the modal assurance criterion at the university of cincinnati, structural dynamics research lab ucsdrl, a little modal assurance criterion little mac1, a big modal assurance criterion big mac and a multiple modal assurance criterion multimac3 were formulated as part of the original development. June, 2018 system requirements artemis modal is a software platform designed for microsoft windows 64bit operating systems. Pmac partial modal analysis criterion comac coordinate modal assurance criterion mif mode indicator function ce lsce complex. It thus becomes possible to provide improved modal assurance criterion estimations where, for each modeshape, sensors known to be incorrectly identi.