Introduction high aspectratio wings have been studied with the objective of improving aircraft performance. The modal assurance criterion mac introduced in 23. The mac and comac factors may be mentioned in this category. Technical specifications for the artemis modal 5 last update. 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. Model calibration of a vehicle tailgate using frequency response functions. 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. Some of the other assurance criteria that will be discussed include the coordinate modal assurance criterion comac, the frequency. How can i compute the modal assurance criterion of experimental. Below the majors benefits are listed along with a listing of all available techniques of the different versions of artemis modal. Download citation the modal assurance criterion twenty years of use and.
Experimental modal analysis by dr mohit law, iit kanpur. Criterion behaviour which focuses only on the eigen values and eigen vectors. Modal correlation of test and analytical data is an. Spatial correlation of modeshapes, the coordinate modal assurance criterion comac, 1995. Taking the classical modal assurance criterion mac, the need to. You can also generate trajectories using polynomial equations, bsplines, rotation matrices, homogeneous. Orthogonalizing a set of mode shapes using the grammschmidt algorithm. The application of modal analysis underpins the theoretical and practical modelling of structural dynamic performance. Finiteelementmodel updating using computional intelligence. Lets say you have a figure, and that figure contains an axes object with handle haxes. Defines degrees of freedom in the reduced eigendata set eset used for modal assurance criterion mac analysis. Coordinate transformation yields statespace models with different matrices but identical dynamics. 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. Model calibration of a vehicle tailgate using frequency.
Apart from this, it has been developed a graphic interface in matlab that implement the modal analysis. Some of the other assurance criteria that will be dis cussed include the coordinate modal assurance criterion. Modified modal domain analysis of a bladed rotor using. 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. Lieven and erwins proposed a mode shape based damage indicator named the coordinate modal assurance criterion comac. Based on your location, we recommend that you select. 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.
Nonlinear aeroelastic scaling studies of high aspectratio wings. Taking the classical modal assurance criterion mac, the need to diagnose sensors contributing to poor correlation was identi. Citeseerx document details isaac councill, lee giles, pradeep teregowda. Additionally, this program could be reused for different methods just with few adjustments.
However, the convergence rate becomes slower for the case of multiple damages compared to the case of single damage. Using the function ginput would allow you to select points within the axes. Modal analysis on an exhaust manifold to define a catalyst fe. In a camerabased coordinate system, the points are defined relative to the center of the camera. This study presents matlab tools developed for numerical process of all steps of dynamic vibration test of structures. Using the finite element method presented in the previous section and the matlab code, the damage is supposed to be, each time, in an.
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. The modal assurance criterion is a statistical indicator that is. 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. Matlab is a unique system that can be used for structural and earthquake engineering problems. Heres an example of how you can do this conversion. Spatial correlation of mode shapes, the coordinate modal assurance criterion. Up to six unique digits may be placed in the field with no embedded blanks. 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. The modal assurance criterion is useful for comparing test and simulation mode shapes.
Modes matching, coordinate modal assurance criterion, composite materials, primary quantities. 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. On the classification of normalized natural frequencies for. Robotics system toolbox provides functions for transforming coordinates and units into the format required for your applications. 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. Sensor location in concrete slabs with various layout of. Coordinate systems are used to place elements in relation to each other. I want to visualize 2d coordinate systems in matlab, given the equations of the transformations. Matlab for all steps of dynamic vibration test of structures. 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. Latitude and longitude specify the position of a point on the surface of a planet. Comac coordinate modal assurance criterion daq data acquisition efi effective independence. 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. Application of the craigbampton model order reduction.
Improved modal assurance criterion using a quantification. As described in images in matlab, matlab stores most images as twodimensional arrays i. On the classification of normalized natural frequencies for damage detection in cantilever beam. Modal analysis of structures consists of three distinct steps. Pmac partial modal analysis criterion comac coordinate modal assurance criterion mif mode indicator function ce lsce complex. Phillips university of cincinnati structural dynamics research lab ucsdrl, cincinnati, ohio, usa abstract. Modal assurance criterion mac file exchange matlab. 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. Mode shapes in comsol experted to matlab where processes experimental data. Pdf improved modal assurance criterion using a quantification of. Orthogonality is verified using modal assurance criterion. Modal assurance criterion mac siemens plm community. Timedependent distance between two body coordinate systems. For more information on the spatial coordinate system, see spatial coordinates image processing toolbox.
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. Integer 0 required ci component number of global coordinate. Multiple damage detection and localization in beamlike. Spatial correlation of modeshapes, the coordinate modal assurance criterion. Modal assurance criterion file exchange matlab central. Comac coordinate modal assurance criterion copmeac coordinate pseudo modal energy assurance criterion cpu computer process unit. This could be done in matlab, scilab, python or even excel. Data is represented using either a geographic coordinate system latitudelongitude or a projected coordinate system xy. The modified type of modal assurance criterion values can be achieved from modal assurance criterion with the exact seismic displacement. June, 2018 system requirements artemis modal is a software platform designed for microsoft windows 64bit operating systems. The output, frf, is an h 1 estimate computed using welchs method with window to window the signals.
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. On the classification of normalized natural frequencies. Coordinate systems are an important part of aerospace systems. To learn more about the different coordinate systems, see coordinate transformations in robotics. Taking the classical modal assurance criterion mac, the need to diagnose. Techniques for synthesizing frfs from analytical models hasan g. Different coordinate modal assurance criteria are applied to complement and verify the. I want to generate images which look something like this. To increase speed, it makes use of mathematical libraries from intel.
Coordinate reference systems provide a framework for defining realworld locations. Artemis modal is a powerful and versatile tool designed for the oma, ema, ods and shm analysis. Point compliances represented by a color scale are. Multiple damage detection and localization in beamlike and.
The particleswarm optimization method is also introduced and applied for finiteelementmodel updating and the results are compared to those obtained from. It was found that the new modal mode assurance criterion guaranteed the completeness and. Find, read and cite all the research you need on researchgate. 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. All of novel optimal sensor placement processes were done through femmacttfd code modeled and developed in matlab by authors of this article. How can i compute the modal assurance criterion of. Field definition type default gi grid point identification numbers. It thus becomes possible to provide improved modal assurance criterion estimations where, for each modeshape, sensors known to be incorrectly identi. Citeseerx scientific documents that cite the following paper. Frequencyresponse functions for modal analysis matlab modalfrf. Pdf test analysis verification using open software.
Ecomac enhanced coordinate modal assurance criterion. It thus becomes possible to provide improved modal assurance criterion. Some of the other assurance criteria that will be discussed include the coordinate modal assurance criterion comac, the frequency response assurance criterion. Furthermore, genetic algorithms are introduced and applied to finiteelementmodel updating. Coverage intensity of optimal sensors for common, isolated. Multiobjective optimization based on the coordinate modal assurance criterion comac and cost considerations was considered in the optimization processes. To access locations in images, the image processing toolbox uses several different image coordinate systems as. Coordinate transformations and trajectories matlab.
Modal assurance criterion the modal assurance criterion analysis mac analysis is used to determine the similarity of two mode shapes. Suppose that the mode can fully be activated, then the generalized coordinate, q, of the mode of vibration represents the. The coordinate modal assurance criterion comac is cal. 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. Jan 16, 2020 multiobjective optimization based on the coordinate modal assurance criterion comac and cost considerations was considered in the optimization processes. Then, you can download the excel files and work with your own data. State coordinate transformation can be useful for achieving minimal realizations of statespace models, or for converting canonical forms for analysis and control design. Sep 23, 2015 this function is to compute and plot modal assurance criterion mac matrix between identified mode shapes. All treated theory is implemented in matlab code and these scripts are extensively explained. Macec is a powerful tool that deals with every step in the modal analysis procedure, except for the data collection. The modal assurance criterion twenty years of use and. 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.
Excel macro for mode shapes orthogonalization youtube. The help system is web based, so maximum performance is obtained by having an. Coordinate modal assurance criteria and coordinate pseudo modal energycriteria. Fault identification using neural networks and vibration data. Correlation topics 122901 1 faculty server contact. Comparative study of model correlation methods with application to. 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. 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. Techniques for synthesizing frfs from analytical models. This function is to compute the modal assurance criterion mac between mode shapes. This matlab code implements the fdd technique for outputonly modal analysis.
Spatial correlation of mode shapes, the coordinate modal. A new flexibility based damage index for damage detection. The development of the mac was modeled after the development of the ordinary coherence calculation associated with computation of the frequency response function. 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. Research article a new optimal sensor placement strategy. This function is to compute and plot modal assurance criterion mac matrix between identified mode shapes. Impacts of the weight coefficient and modal assurance criterion of. A graphical method of comparison was found for simple structures, which considers the spatial distribution of the entire frequency response spectrum. Modal assurance criterion mac file exchange matlab central. In this article we present a pedagogical example of using experimental modal analysis to verify and calibrate a finite. Modal assurance criterion mac this function is to compute the modal assurance criterion mac between mode shapes. Xmodal experimental modal analysis software structual.
Damage assessment in reinforced concrete beams using eigenfrequencies and mode shape derivatives. 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. 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. When you reconstruct a 3d scene, you can define the resulting 3d points in one of two coordinate systems. Damage assessment in reinforced concrete beams using. Choose a web site to get translated content where available and see local events and offers. The modal assurance criterion mac is the most widely used criterion for vector correlation mainly because of its simplicity. Improved modal assurance criterion using a quantification of. Coordinates in pixel and spatial coordinate systems relate to locations in an image. Damage detection using flexibility proportional coordinate.
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