Enhancements made to WinTest DMA software.

Features have been added to the company's standard WinTest based dynamic mechanical analysis (DMA) application software, including mixed mode testing, strain or stress control, measurement of specimen height, and new calculations and export features.

The ability to independently define the feedback used for mean control and the dynamic amplitude has been added. During cycling, the test system compensation adjusts for any inaccuracies in the dynamic amplitude, and simultaneously adjusts the total waveform to provide the requested mean level in the requested feedback. These selection options were added to the bottom of the "new condition" window and the "edit condition" window. When an old cycle file is opened, the default setting will be that both the mean and dynamic amplitude will be set to the original feedback mode.

In addition to choosing the independent control for the mean and dynamic amplitude in the "new condition file" definition and "edit condition" window, users can now choose stress or strain control, in addition to the normal feedback selections. Note that when stress or strain is selected, the feedback button is grayed out as the control mode is pre-selected as displacement or force, depending on user choice.

The "load hold" value can now be defined as a variable. This will allow more flexibility in the definition of tests, including allowing studies of the effect of "load hold" values on dynamic properties.

It is now possible to have the test system automatically measure the specimen height (or length) upon contact in compression or minimum tension. The analysis window will now report a Lo and Lm. Lo is the initial specimen height and Lm is the specimen height when the mean condition has been applied.

Lo will be set to the appropriate dimension from the specimen geometry. If the corrected sample height is chosen, the software will add the displacement reading at the load hold value for each test condition to the sample height for the cylindrical or rectangular specimens. To implement this approach, use a gage block equal to the dimension entered in the "specimen geometry" to determine the gap between the fixtures, and zero the LVDT with the gage block defining the opening.

If strain control is chosen, then the new specimen height is used to calculate the displacement required to apply the requested strain for mean or dynamic amplitude.

Also note that the "load hold value," "mean level rate" and "temperature rates" have been moved to the "new condition definition" window and the "edit condition" window to consolidate all the test definition values into one user interface window.

New options have been added to the export function. Users may now export all relevant calculations available. For example, if specimen geometry has been entered, the specimen stiffness and modulus can be exported. If no geometry has been defined, only the specimen stiffness is available.

There is now an option to export up to two temperature channels. This provides the ability to control the air temperature of the chamber and record the internal temperature of the sample being tested, or a dummy sample exposed to the same temperature conditions.

Users may also create a column of hysteresis properties. This calculated parameter may be found in ASTM D5992 and assumes the hysteresis loop is a perfect ellipse.

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