TMM-04 torsion test machine Users manual MRG Infó BT Budapest
Contents
1. the required one The other rate parameters are re scaled by the ratio of the given Rate at the beginning and the value of the first rate parameter in the program file This does not effect the level values Emergency limits can also be set here If during a test the torque the elongation or the rotation angle reach the limits set in the corresponding menu point the test User Manual MRG Info BT 15 is stopped This also happens if the torgue reaches the maxima that the load cell can balance without damage 6 RUNNING TEST 16 6 Running test Torsion measurement test dat test Status Running Axis get X axis Y axis Zero Add proc Sampling rate ms 2 2 Modamp rad D 1 Modf req Hz 6 1 gt 6 62 Modulation Off Next Hold Back Function Print Help SavetQuit 5 Angle rad Figure 9 Test menu After the sample is mounter and the parameters of the O t function are selected the system is ready to perform the torsion test For this purpose the windows which can be seen on Fig 9 should appear The test can be started stopped by clicking on the menu point Status The plotting and the performance of the test can be manipulated by the other menu points as follows Axis get It selects the active vertical axis The torque is plotted in green the elongation is in red and the angle is in light blue X axis The scale on the horizontal axis can be increased decreased by a factor of 2 by cl2. O t program files should be placed in the directory usr local torsion functions Several previously written function can be found in this directory The required function can be selected in the Measuring speed parameters menu see Fig reff6 After clicking on the Functionname menu point a sub windows listing all the available program file should appear see Fig reff7 The first clicking on the required filename would draw the function curve A second clicking on the same one would select it 5 SELECTING MEASURING MODE AND DEFORMATION RATE 14 Zusr local torsion functions fun 1 cos fun compress fun crectan fun defstep fun linear fun rectang fun sin fun trectan fun Figure 8 Selecting program file In order to increase flexibility the rate and level parameters given in a O t program are relative The maximal value of the program function can be selected by the Amplitude menu point This does not effect rate values just the levels It re scales them to have the maximum of the function the required one The total signal time can be set the required one by the Signal Time or Frequency menu points These do not affect levels but the rate and time values They are re scaled to have the required total signal time It is often convenient to set the rate of the first program segment directly This can be done by the Rate at the beginning menu point It sets the initial rotation rate to
3. TMM 04 torsion test machine Users manual by Dr I Groma MRG Info BT Budapest http www mrginfo com e mail groma metal elte hu TURG nio Bt 2005 CONTENTS Contents 1 Introduction 2 Starting the measuring so tware Using the Main menu Calibration Selecting measuring mode and deformation rate Running test 10 12 16 User Manual MRG Info BT 3 1 Introduction TMM 04 is a general purpose free end torsion test machine The system is fully Figure 1 TMM 04 torsion test machine computer controlled The rotation is driven by a precision 3 phase Berger Lahr stepping motor The stepping pulses are provided by the computer This results that the time variation of the rotation angle can be programmed by the user between wide range of limits This allows to perform many different types of torsion testing During testing the rotation angle the torque required and the sample elongation are recorded with a hight performance 16 bit analog to digital converter The torque is measured by a 200N load cell HBM S2 The change of the sample length is detected by an inductive transducer HBM WI Data are collected and plotted by the computer with 0 5KHz sampling rate In order to achieve this sampling rate a Real Time Linux operation system is used for details visit http www rtlinux org which is a modified version of a Mandrake 9 0 Linux system By replacing the usual Linux system kernel with the Real
4. Time kernel it can be guaranteed that a torsion machine controlling task is performed at each 100us independently from the actual load of the computer The parameters of TMM 04 are the following 2 STARTING THE MEASURING SOFTWARE 4 Maximal rotation rate 2 rad s Angle resolution 0 36 Maximal torque range 50 Nm Torque resolution 0 02 Nm Elongation range 5 mm Elongation resolution 0 1m Maximal sample length 110 mm Maximal sample diameter 8mm Maximal data sampling rate 500 s7 2 Starting the measuring software Beside Real Time Linux RTL other operation systems are also installed on the controlling computer Shortly after the computer is turned on a boot menu should appears on the screen For performing torsion tests rtlinux has to be chosen This is the default boot mode so if another one is not selected RTL starts automatically within a few second For security reasons the TMM 04 controlling software can be run only by a ded icated user called torsion So after RTL booting when a login screen appears one has to login as torsion user The password is provided by the system administra tor For starting the controlling software called torsionmeasure either run torstonmeasure from a xterm window or click on the torsion icon It is important to note that the controlling software cannot be started twice If a second one is launched by mistake it is automatically killed by the system So if t
5. cally increased by the system after each measurement file saving The full filename is combined from the path the filename and the extension like see Fig 2 home torsion measure number test dat User Manual MRG Info BT 7 Path The directory where the measuring data file is saved can be set by this menu point After clicking on it a sub menu appears see Fig 3 listing the existing directories within the directory selected before The actual directory can be changed by clicking on the reguired directory name If the reguired directory is reached press Esc to get back to the main menu Desktop Documents MailZ measure tmp Figure 3 Main menu Extension The extension of the measuring data file can be selected by this menu point Identifier An arbitrary one line length text can be set by clicking on this menu point The date of the measurement is automatically added to the end The identifier is saved at the top of the measuring data file Measuremode With this menu point one can select which of the measured data and how they are plotted during measurement By clicking on the menu point 3 USING THE MAIN MENU 8 one can choose from the valid modes The horizontal axis can be time or angle Depending on the mode selected the measured torque elongation angle and load the measure of load is not implemented yet can be plotted simultaneously as a function of time or rotation angle Lengt
6. eters menu The parameters can be changed Print This menu point prints the measuring plot that can actually be seen on the screen The printing creates a postscript file In order to send it to the printer press Sendprintout in the main menu The ps file can be converted to jpg format by the command convert filename ps filename jpg Help A help window explaining the usage of the measuring menu can be get by this menu point 6 RUNNING TEST 18 Torsion measurement test dat test Status Stop Axis get X axis Y axis Zero Add proc Sampling rate ms Number of saved data 5761 Save Save as home torsion measure Stest dat odfreg Hz 6 82 lodulation Off Next Hold Back Do not save Quit Function Print Help SavetQuit Figure 10 Save menu Save Quit Ifthe test is finished the measured data can be saved under this menu point By clicking on it the sub menu that can be seen on Fig reff9 should appear In the first line the total number of collected data points is given By changing it to any smaller number would cause to reduce the number of saved data points to the given number Data are selected homogeneously from the total data set collected The usage of the other sub menu points are obvious If the controlling electronics in not on or for some reason the stepping motor is overheated a message The motor is not ready should appear on the screen In this case check the s
7. h The length of the sample should be given here in mm Cross section After clicking on it one is prompted for the diameter of the sample in mm The cross section is calculated automatically Axis mode The position of the 0 0 coordinate can be selected by this menu point By clicking on it one can select from the valid modes which are the following left bottom center bottom right bottom center center right top Torgue axis The scale of the torgue axis should be defined here It needs to have a nonzero starting value but it can be changed during the measurement Elongation axis The same as explained before for torgue but for elongation Angle axis The same as explained before for torque but for angle Depending on the measuring mode the value given can correspond to either the horizontal or the vertical axis Torque amp In order to increase the flexibility of the instrument a programmable internal amplifier is built in the controlling electronics The signal coming from the load cell is amplified by the selected factor 2 5 10 So if during the test the required torque is considerably smaller than the maximal measurable torque 50Nm at the current setup it can be useful to select an appropriate amplification Elongation amp The same as explained before for torque but for elongation Measuring time The scale of the time axis should be defined here It needs to have a nonzero starting value but it can be changed duri
8. hat one has to give is the slope of the given segment and the angle up the that the function goes with this rate Funct ionname rectang fun fmplitudo rad 188 Signal Time s 2668 Frequency Hz 5E 4 Rate at begin rad s 2 0 1 Torque max Nm 49 5 Torque min Nm 49 5 Elong max Emm 5 Elong min mm st Angle max rad 1888 Angle min rad 1888 Help Exit Figure 6 The O t function selection menu The definition of a O t function is a sequence of statements like 1R 1A 1R 0A where a statement with form number R defines that rate number and number A means that the function goes with the current rate up to level number see Fig User Manual MRG Info BT 13 Angle Time Figure 7 The discresitation of O t function 7 The above example defines a triangle see Fig 6 It is important to note that the rotation rate needs to have a nonzero positive value The actual rotation direction is determined by the current and the target angles So if we are let say at 5 rad and the next statement in the program sequence is 10A the angle will increase while if it is 5A the angle will decreases with the given rate The example below defines a triangular wave like O t function 1R 4A 1R 4A 1R OA Since a statement 0R would hold the stepping motor at the current angle forever to hold the angle for a given time time the statement time T should be used The
9. icking the left right mouse button respectively The curves are automatically re plotted User Manual MRG Info BT 17 Y axis The same for the active vertical axis Zero It sets the current torgue and elongation to zero Add proc Two separate cursors can be placed by this menu point Sampling rate Data sampling interval can be set by this menu point The min imal time interval between two measured data is 2ms It can be modified during measurement too Modamp The system allows to add a sinusoidal modulation to the programmed O t function The amplitude of the modulation can be set by this menu point It cannot be larger than 1rad ModFreq The modulation frequency can be set by this menu point Modulation Modulation can be started stopped by clicking on this menu point We have to say at this point that the modulated test is a new feature There is only a very limited experience with this type of testing so far Any suggestion for improving it is warmly welcome Next The performance of the test can be influenced by this menu point By click ing on it would force the system to stop the current O t programming segment The system continues with the next one Hold By clicking on it the stepping motor should stop By another clicking the O t program should continue with the next programming segment Back It turns the motor back to zero angle Function By clicking on it one can get back the Measuring speed param
10. n read this manual by clicking on this menu point Exit torsionmeasure has to be terminated by clicking on this menu point Al though under Linux there are many other way to terminate a task in order to avoid uncompleted termination it is strongly recommended to use this Always Exit before logging out or shutting down the computer Never turn the computer off before shutting Linux down This can damage the file system 4 CALIBRATION 10 4 Calibration During the torsion test the torque required at the given rotation angle is measured by a load cell positioned between two bars One of the bars is fixed to the frame of the instrument the other one to the stepping motor which can rotate freely see Fig 4 The torque developed within the sample would rotate the whole stepping motor but it is balanced by the load cell In order to increase the flexibility 4 ali TA a jJj 228 sveds uepeueg oy ym uoneioqeyjoo j ouuoipeues 610 00za2edsaujurmmm Z few 0 6z jude wory pew z ne june ez ng s T 7 THEE MN A Figure 4 Method of torque measurement of the instrument the distance between the torsional axis and the load cell can be varied see Fig 4 Thus for the calibration of the torque measurement the distance between the load cell and the rotation axis should be measured Since this might not that easy to measure with the appropriate precision one has to measure only the distance between the edge of
11. ng the measurement User Manual MRG Info BT 9 Set temperature The measuring temperature can be given by this menu point In order to start heating cooling chamber status needs to be On Chamber Status Chamber heating cooling can be On or Off by clicking on this menu point It is strongly advised to turn off the chamber during sample change Calibration The calibration sub menu can be started by clicking on this menu point The details how to calibrate the instrument are explained in the section Calibration Measure This menu point starts the measuring windows Details are explained in section Running test Rotate By clicking on this menu point with the left or right button of the mouse the stepping motor turns plus or minus 1 respectively This can be useful during sample assembling Unload The sample can be unloaded with this menu point The stepping motor turns until the torque becomes zero This can be useful for getting out an unbroken loaded sample Sendprintout The printed figures see under section Running test are not di rectly sent to the printer They are printed into ps files The files are located in the tmp mprints directory They can be saved manually by copying them to a different place In order to print them one has to click on this menu point After this the files are deleted The unprinted figures are also deleted at the startup of torsionmeasure Help One ca
12. orsionmeasure halts after the appearance of an initializing icon it has to be checked if there is another running torsionmeasure task The command ps aux User Manual MRG Info BT 5 lists all the running processes Since torsionmeasure can be run rom a remote Linux system too it can happen that one cannot directly see on the screen that torsionmeasure is already running We mention here that the TMM 04 controlling software is installed in the usr local torsion directory Care should be taken not to destroy it 3 USING THE MAIN MENU 6 3 Using the Main menu After starting torsionmeasure the window that can be seen on Fig 2 should appear The description of the menu points are the following Filename proba2 Path home groma Extension dat Identifier proba meres Measuremode time torq elong angle Length mm 18 Cross section mm 2 28 Axis mode xy Left Bottom Torque axis Nm 188 Elongation axis mm 16 Angle axis rad 188 Torque amp i Elongation amp 1 Motor is not ready Load N Measuring time 188 Set Temperature 76 gt 388 C 25 Actual temp 364 6 C Chamber status Off Calibration Measure Rotate lt gt Unload Sendprintout Help Exit Figure 2 Main menu Filename The name of measuring data file can be set by this menu point In order to avoid overwriting existing file an internal number is added to the selected name The number is automati
13. the stepping motor an the marker on the load cell see Fig 4 The rest is automatically added If it is necessary both the load cell used for torque measurement and the dis placement transducer can be replaced by another one HBM offers several different ones Their measuring limits the force or displacement corresponding to 10V out User Manual MRG Info BT 11 Filename test Force Box N 288 Distance mm 285 Elongation Box mm 5 Help Exit Axis mode xy Torque axis Nm 8 39862 Elongation axis mm 2 5 Angle axis rad 12 5 Torque amp 1 Elongation amp 1 Load N 8 Measuring time 588 Set Temperature 78 gt 380 C 28 Actual temp Calibration Measuring speed parameters Measure Rotate lt gt Unload Sendprintout Help Exit Figure 5 Calibration menu put signal should be given For the load cell shipped presently the limit is 200N while for the displacement transducer it is 5mm The calibration parameter can be set in a sub menu appearing after clicking on the Calibration menu point in the main menu see Fig reff5 5 SELECTING MEASURING MODE AND DEFORMATION RATE 12 5 Selecting measuring mode and deformation rate The time variation of the rotation angle O t can be programmed by the user Within certain rotation rate limits practically any Q t function can be applied The required O t function has to be composed from linear parts referred to segments hereafter W
14. ystem User Manual MRG Info BT 19 Enjoy your work
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