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RHEA (Rheology Analysis) - Updates   

Version  1.2.1 - July 11, 2011


Allow mores Anton Paar data sets to be analyzed.  In addition, the software now outputs a file with a GKM extension than can be used with the STP - simulate test pulse - software.  This allows users to look a what happens in a repeated creep test - with the assumption of linear visco-elastic properties.

Version  1.1.9 - May 25, 2011

Corrects a problem with phase angles of 90 degrees or greater being reported in some data files resulting in a program crash.

Version  1.1.8 - May 24, 2011

Corrects a problem with data not being saved in correct temperature order for some *.apr formats when converted to *.ttd files.

Version  1.1.7 - May 16, 2011

This Rhea version enables four file formats generated by three versions of Anton Paar RHEOPLUS/32 software, versions V2.81, V3.21, V3.31, to be read by the RHEA software. Export the data from the software which will be in a "csv" format (comma separated file). After the data has been exported change the extension of the file from ".csv" to ".apr." The ".apr" identifies to RHEA that an Anton Paar file format is expected.

Version  1.0.8 - July 20, 2010


This Rhea version completes the following updates:

1- Right-Click context menu on MasterCurve plots has a new item "View MC data". The shifted observed data points (or equivalent pseudo-points) within the mastercurve are listed and can be copied to the clipboard. Thus numerical values of complex modulus, phase angle, dynamic viscosities etc of the mastercurve can be inspected and saved.

2- The formulae for the discrete spectra Storage and Loss Modulli have been included with the spectra listing (besides those of the Relaxation Modulus and Creep Compliance).

3- Mastercurve at Tref added to Accessible Region plot.

4- Several bugs fixed related to use of radians per sec vs. Hz frequency measure in the data input. These caused some results of analysis of rad/sec data to be inconsistent with analysis of same test input as Hz data. Specifically:

a) Oberst damping optimum temperature

b) Y axis annotation of dynamic viscosity

c) Magnitude of some listed Discrete Spectra components

d) some values in the properties dialog - Relaxation modulus, Creep log log slope, Dynamic viscosity.

5- Properties dialog split into two sections, first for Time domain (transient) and second for Frequency domain (dynamic) properties, to clarify how time and frequency inputs are applied.

6- Two additional properties: Apparent stiffness and Loss Dynamic viscosity.

7- Properties dialog now responds to Windows "Show Desktop" command.

Version  1.0.7 - May 17, 2010

This Rhea version corrects some software bugs but more importantly now includes the Kaelble modification to the WLF Shift factors.

Version  1.0.4 - March 18, 2010

This Rhea version corrects an error that occurs with HMA mixture data files when a slow loading data point is added to the highest temperature isotherm. This is just an exe file replacement. Make sure you have installed the 1000 version software before replacing the exe. A new full install package will be available in the next week with some new additional features.

The version add to 1.0.2 that was added the previous week to correct and improve Anton Par file handling.

Version  1.0.0 - Jan 2, 2010

Changes [from v.0.9.9999] for Rhea v.1.0.0 2010-Jan-02

The changes made relate just to technical correctness of the Discrete Spectrum 
Listing, as follows.

1) In the Discrete Spectrum Listing, there were unbalanced parentheses in the 
Logistic-Fit equations.

2) In the Discrete Spectrum Listing, the time constants of the elements of the
Generalized Kelvin Model were incorrectly referred to as Relaxation times 
whereas they are actually Retardation times.

Version  0.9.9998 - April 21, 2009

The current version of RHEA™ Software is updated to 0.9.9998

It was noted that the modified CA fit to G* data alone was not always working whereas a fit was always provided for G' G" data.  This version was updated to correct that a results in the program giving a CA fit in all known cases for the G* alone.  The type of fit is the CAS version of the CA equation - which is a three parameter fit with a variable glassy modulus.

Version 0.9.9997 - September 30, 2008

Mechanistic-Empirical Pavement Design Guide
In preparation for the introduction of the MEPDG work has been conducted to represent the output of mixture data in this format. Two windows provide this data - first using the polynomial shifting the shift is represented in the standard logistic sigmoid used in the MEPDG. Frequency is converted to time using the approximate relationship and E* is the expressed as a function of loading time.

A second expression of the results is provided under the listing of the output. The model used in the MEPDG is called the "standard logistic." In addition to the fitting parameters a measure of the fit is provided via the root mean square analysis. The expression given in this equation is in terms of frequency which is the rheologically correct manner of expressing E* data.

Alternate Sigmoid
In addition to the sigmoid in the MEPDG format an alternate format is provide as the Richards curve. In some cases this is expressed as a limiting Gompertz curve. These sigmoid allow for non-symmetrical sigmoid formats more typical of asphalt materials. In addition, Abatech has found that this type of expression more correctly accounts for the behavior of polymer blends and those with significant filler volume.

Solid vs. Liquid Analysis
Additional functionality has been provided allowing the user for force either a visco-elastic solid or liquid analysis (partly dependent upon data) along with the calculation of discrete relaxation and retardation spectra.

Oberst Analysis
The Oberst test is used in industries concerned with damping properties. The Oberst results can be calculated from a frequency sweep analysis/master curve thus allowing prediction of this test data at different frequencies and temperatures.



File Formats
We have been working with the integration of Signal data from both IPC and Interlaken data sets to produce analysis of material master curves.

IPC data - RHEA will handle IPC data - sum files in the file reader.
TA data - If TA data is exported from TA software in a prescribed manner then RHEA will handle this in the file reader to make a ttd file.

Various other updates have been made

  • WLF is allowed with grater or equal three isotherms
  • Pairwise shifting graphs are provided
  • G* or E* can be used alone to produce shifted curve - with a calculated phase angle from the discrete spectra fit

Planned Updates for 2009

  • Additional work will be conducted on the V-E solid master curve fitting.
  • Further evaluation of Kaelble shift factor