Together with the results file, a graphic display of thedistorted structure (Draw the mesh), the voltageresponse (Transmitting Voltage), the sensitivity (
The user can also use ISOVAL to plot contours of constant value (iso-displacements, iso-potentials, iso-pressures,iso-stresses, etc.) on the modeled structure. ISOVAL can be used only if the generation of the PST file wasrequested in the job’s data file (see chapter III and paragraph
When dealing with underwater piezoelectric transducers, thedesigner needs to know the electrical impedance, generally given as anequivalent parallel circuit composed of a resistance and a capacitance. The
The frequencies provided in the data file are plotted byfitting a spline curve to the input data. The values of the parallel resistanceand of the parallel capacitance as a function of the frequency are in the
Using the Draw parameter button, onecan choose a linear scale or a logarithmic scale for the frequency axis. Moreover, the frequency can be normalized(Reference frequency).
Note: If the symmetries detected by the solver areincorrect, the user has to correct the values of Rp/Cp as well as the values ofRjX.
When dealing with underwater piezoelectric transducers, thedesigner needs to know the far field pressure in the fluid medium and itsspatial distribution. He might also need to find out its sensitivity, which canbe calculated from the transmitting voltage response and the electricalimpedance via the reciprocity equation. The directivity index may also bevaluable information. These parameters are available using the
The transmitting voltage response is the magnitude of thefar field pressure, expressed in dB, ref. 1 mPa/Voltat 1m.
The sensitivity (voltage magnitude measured on thetransducer for an incoming plane wave) is expressed in dB ref. 1 Volt/
These plots are made for different directions, as a functionof the frequency. The Copy command enables you to storethe values in an Excel file.
Using the radio buttons appearing in the Draw parameters dialog, the directivity index (for atwo-dimensional structure) can be plotted. It describes the increase of sourcelevel compared to the omni-directional case. The user can also change the
Inthe .ATI data file, the user must ensure that theexcitation voltage magnitude is 1 Volt (which is the reference level). Thefrequencies provided in the data file are plotted by fitting a spline curve tothe input data.
When dealing with underwater piezoelectric transducers, thedesigner needs to know the far field pressure in the fluid medium and itsspatial distribution. The aim of the Directivities button is to provide plots of the far field directivity patterns for severalfrequencies.
In the .ati data file, the user mustensure that the excitation voltage magnitude is 1 Volt (which is the referencelevel). Patterns are plotted by fitting a spline curve to the computed data.
The Directivities command uses a .pat file containing information about the far field pressurethat the ATILA solver creates. This file can berecreated from the .sy4 file (which is also created duringthe computation).
Initially, a quarter of the directivity pattern is drawn forthe first six frequencies. Using the Draw parameters dialog, it is possible to plot 1, 2 or 4 quadrants. Using the Copy command, the diagrams can be inserted into any text file.
Initially, a Simple mesh is displayed. Draw parameters modifies the display. Thebuttons are similar to those from pre-processing, except that Draw parameters reads a .sy4 file created aftersolving the problem with ATILA, instead of the datafile. It also has buttons for dynamic views that are described below.
· Displaced structure: full lines, rest structure: dashed lines.This option is used to plot the deformed shape of a structure. The solidelements of the structure at rest are shown with a dashed line, while those ofthe deformed shape are shown with a full line. Fluid elements and nodes do notappear.
The user can modify the selected frequency (harmonic or modal analysis) or selected time (transient analysis), and the
· Displaced structure: full lines, no rest structure. This optionis identical to the previous one, except that the mesh at rest is not shown.
· Electrical iso-potential lines in 2D elements. This option isused to plot iso-values of the electric potential magnitude in piezoelectricdomains of a two-dimensional mesh. The solid elements of the structure areshown with a full line. Iso-values of the electric potential magnitude areshown with a full line, except the null iso-value, which is shown with a dashedline. Fluid elements and nodes do not appear.
The user can modify the selected frequency (harmonic ormodal analysis) or selected time (transient analysis). No frequency value isrequested for a static analysis or when solving was performed for one frequencyor time only.
· Isobaric lines in 2D fluid (magnitude). This option is used toplot iso-values of the pressure magnitude in fluid domains of a two-dimensionalmesh. The fluid elements of the structure are shown with a full line. Iso-valuesof the pressure magnitude are shown with a full line, except the null pressureiso-value, which is shown with a dashed line. Solid elements and nodes do notappear.
The user can modify the selected frequency (harmonic or modal analysis) or selected time (transient analysis). Nofrequency value is requested for a static analysis or when solving wasperformed for one frequency or time only.
For magnetic and magnetostrictive domains, the followingoptions are available.
· Magnetic B field in 2D elements (magnitude). This option is usedto display vectors of the magnetic field B in magnetic or magnetostrictivedomains of a two-dimensional mesh. The magnetic field includes the rotationalpart coming from the magnetic sources and the irrotational part deduced fromthe magnetic potential. The magnetic and magnetostrictive elements of thestructure are shown with a full line. Magnetic field vectors are shown with afull line, starting from Gauss integration points, and of length proportionalto the magnitude. Fluid elements and nodes do not appear.
The user can modify the selected frequency (harmonic ormodal analysis) or selected time (transient analysis). No value is requestedfor a static analysis or when solving was performed for one frequency or timeonly. When a complex solver has been used, two graphics are provided. Thesecorrespond to the real and imaginary parts of the magnetic excitation field(remember that the real value is the real part of the product of the complexvalue and the time dependency, which is ejwt in ATILA).
WISOVAL is an interactivepost-processing graphical program for the creation and display of a shading orcontour plot of results of an ATILA run (a shading plotis the default). WISOVAL displays in different colorsthe variation of a scalar value throughout the domain under study (iso-valuesof the displacement field components, of the stress field, iso-potentials, iso-pressure,etc.). Iso-values are always represented in a plane. These can be plotted onthe outer surface of a structure or in a cross-section.
WISOVAL requires the data stored inthe post-processing file .pst. This file is generatedby ATILA if a GENERATION PST entry has been provided in the .ati data file beforeusing the solver (see Chapter III). If this command does not appear in the
Initially, the X-displacement is displayed for the first frequency input in the .ati file.
Edit and Option commandsmay be used.
In the Edit menu, Axes (see section I.F) and Draw parameters are available. The plot type may be selected: Displacement in the x direction (Ux),in the y direction (Uy), in the z direction (
In the Option menu, the mainavailable commands are: Legend, to show or hide thelegend on the right, Mesh, to show or to hide the fulllines of the mesh, Node numbering, to show the nodesnumbers and Element numbering, to show the elementsnumbers. Using Color scale, one shaded color can beselected, and Composite combines different options.
Animate performs animations. Infact, it can animate the displacement Snapshots that are equally spaced in onecycle of the harmonic response and are created from the .sy4 file that the solver creates.
By moving the arrow on the screen, the view angle ischanged.
The main available options are: Select frequency, Animation, Pause. With Animation properties, Frequency and magnitude may be changed. Wire mode displays the structure in wire frame view. Colors and materials may be selectedand changed using the Select material button.
The color white is assigned to any new material created. Tomodify this color, click on Material, then on Add the material.
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