IMAT is a toolbox that allows you to access function, time history, shape, result, and finite element model (FEM) data from Siemens NX, I-deas Test
An important feature of the toolbox is that you have access to all of the I-deas data attributes from MATLAB. These data attributes include data type information (acceleration, displacement, sound pressure, etc.), as well as function types, descriptive information, coordinate labels, etc. All of this information is carried with each function when you import it, and you can both examine and modify the attributes.
IMAT also consists of several additional toolboxes, grouped by functionality. IMAT+FEA, IMAT+Modal, and IMAT+Signal are described in more detail below.
This user guide describes the MATLAB data types and operations provided in IMAT that allow you to manipulate functions and other entities.
Here is a summary of the features of the IMAT toolbox:
f.functiontype='Order Function'
the toolbox automatically substitutes the proper numeric value to represent an order function.
>> t=imat_ctrace('1001x','1002y','1003z-');
>> f_top = f{t}; % Selection using a coordinate trace
>> z=imat_filt('responsecoord',
'=', '100?z*');
>> f_up = f{z}; % Selection using a filter
IMAT+FEA allows the user to interface with several different analysis packages including NASTRAN®, Femap, and Abaqus. In most cases bi-directional support is provided. IMAT+FEA functions are marked with a +FEA next to the documentation. You can read more about IMAT+FEA here.
IMAT+Modal provides functionality geared toward the modal test engineer. IMAT+Modal provides capabilities for generating Test Analysis Models (TAMs) in NASTRAN through the TAMKIT functionality, optimal accelerometer selection using a genetic algorithm (GA) and a brute-force method (selectASET), and many routines for processing modal test data. OPoly is a polyreference modal parameter estimator with two orthogonal polynomial algorithms to choose from. MIFODS produces operating deflection shapes by picking peaks from mode indicator functions. SDOFit is a single degree-of-freedom modal parameter estimator that is also included. IMAT+Modal functions are marked with a +Modal next to the documentation. You can read more about IMAT+Modal here.
IMAT+Signal extends IMAT by providing functionality that facilitates signal processing, both with stationary and rotating signals. In addition to command-line functions, spFRF is a GUI that provide an easy-to-use interface for processing stationary signals. spView is a GUI that allows users to easily compare results from multiple datasets. RTK is a GUI that encapsulates the process of obtaining response characteristics and finding insights into the mechanics of rotating events. It applies the Vold-Kalman filter technique to order-tracking of rotational events. IMAT+Signal functions are marked with a +Signal next to the documentation. You can read more about IMAT+Signal here.
IMAT gives you several different ways to transfer data between different software packages and MATLAB.
The most direct and efficient method is to directly read and write I-deas and NX ADFs (associated data files) from within MATLAB, using the readadf and writeadf functions.
Toolbox functions are provided for reading and writing Universal data files from within MATLAB. The Universal files can be used to transport data to and from I-deas and any other software package that supports the format. The readunvand writeunv functions operate on universal files containing functions, time histories, mode shapes, coordinate traces, degree of freedom sets, and finite element geometry, including coordinate systems, nodes, elements, and tracelines. The readunv and writesubst functions operate on universal files containing substructure matrices (mass, stiffness, back expansion) for I-deas Test/Correlation. You can also extend the import capabilities of readunv by writing your own dataset plugins. The Extending Readunv guide steps you through this process.
IMAT+FEA supports importing NASTRAN data from Output2, Output4, punch, bulk data, and DMI and DMIG-formatted files. The readnas function can import OP2 and bulk data files. Not all data types within these files is supported. The documentation for these functions specifies what data types they can read.
You can write records to an Output2 file using writenas and its companion function create_op2table. You can also write matrices to Output4 format using writeop4. In addition, you can write limited bulk data using writeblk and several other related functions found in the examples directory.
IMAT+FEA supports importing Abaqus data from ODB files. The readodb function supports xyData, and history and field objects on a step. This data is imported as imat_fn, imat_shp, and result objects as appropriate.
IMAT+FEA supports exporting data to Femap through the Neutral file or directly to a Femap session through the COM interface. The writeFemap function supports imat_fn, imat_shp, result, imat_fem, and imat_group. You can also import some datasets from Femap Neutral files using readneu.
One of the powerful features of I-deas is its ability to change unit systems "on the fly". This is handled internally by storing all information in SI units, and presenting results to the user in whatever unit system is currently selected.
A different scheme has been implemented for handling units in MATLAB with the IMAT toolbox. With IMAT, you must preselect the unit system you will be working in (using the setunits function). You can select one of the nine built-in unit systems, or you can define your own units. When you read data from Universal files or ADFs, the numeric data will be stored in your selected unit system. The units also come into effect when you write data to these formats. The getunits function tells you what unit system you are working in. IMAT assumes that data imported from NASTRAN and Abaqus is stored in the current units system in MATLAB.
You can call setunits at any time during your MATLAB session to change your working unit system. Unlike I-deas, however, this will not automatically change the numeric values of existing data. Some data types such as imat_fn and imat_shp have methods named chgunits that convert your data to a different units system. It is the user's responsibility to maintain a consistent unit system while working in MATLAB. (If you always work in the same unit system, you may find it convenient to put a call to setunits in your startup.m file.)
I-deas does not have a G units system for acceleration data. However, IMAT has implemented this capability through a modifier to the units system specified with setunits. If this modifier is applied, all data that is tagged as acceleration will be treated as G's rather than engineering units. The modifier is as simple as appending a 'g' to the units specifier or toggling the acceleration units treatment on the setunits form.
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