A new version of VibrationVIEW (2020.1) is now available for download. In this latest software release, access additional MIL-STD-810H updates, enhanced SRTD capability, and more.
International Electrotechnical Commission (IEC) Signal Tolerance Requirement
The Sine package will now report the channel RMS parameters for both the filtered and unfiltered signal. As defined by IEC60068-2-6, a graph must be generated to show the signal tolerance if it is listed in the test specifications.
“Acceleration signal tolerance measurements shall be performed if stated in the relevant specification. They shall be carried out at the reference point and shall cover the frequencies up to 5 000 Hz or five times the driving frequency whichever is the lesser. However, this maximum analysing frequency may be extended to the upper test frequency for the sweep, or beyond, if specified in the relevant specification. Unless otherwise stated in the relevant specification, the signal tolerance shall not exceed 5 %” (4.1.3).
The equation for signal tolerance is as follows:
Addition of a Meter-Hz Unit
A meter-Hz unit has been implemented. When a component of a product has an exceedingly high resonance, this displacement-frequency unit can help to ensure the test is applying the same fatigue to the product as a whole.
Sine Resonance Tracked Dwell (SRTD) Units
A constant acceleration, velocity, or displacement dwell can be defined in a different AVD unit than the test profile. During phase tracking, the software converts the units and adjusts them based on shifting frequencies and phases in the product’s resonance.
In VibrationVIEW 2020.1, the unit conversion has been simplified. The user can now enter the profile for the resonance sweep in acceleration units and control the dwell in velocity or displacement. The most common application of the SRTD units is a sine sweep with the profile defined in acceleration and the dwell portion of the test defining a fixed displacement on the resonant point.
Tolerance Requirements for Sine Tests
See “Table 514.8-III. Sinusoidal Vibration Test Tolerances” (358)
The Sine package now includes the new Sine test tolerances defined in MIL-STD-810H. The new requirement is applicable when extremal or average control is used.
Test profile tolerances apply to the composite trace: the maximum, minimum, or average of multiple selected control channels. MIL-STD-810H defines additional tolerances for the individual channels that comprise the composite trace. The individual channels used for control must fall within specified tolerance bands to meet the test standard. In the newest software version, the user can enter the appropriate tolerances for both the composite control trace and the individual channels.
In VibrationVIEW, tolerances can differ based on frequency and users can set the tolerance for the channels and control. This is true for Random tests as of version 2019.2.
Updated Definition of SRS Test Parameters
See MIL-STD-810H METHOD 516.8 ANNEX A
Parameters Te and TE are used to identify the duration of a shock test and when the energy is most concentrated. According to MIL-STD-810H “…Te is now defined from the zero crossing for the first measurement acceleration ‘above the instrumentation noise floor’ until the perceived ‘termination’ of the shock…” The revised definition of TE is “based on the minimum length of time that contains any time history magnitudes exceeding in absolute value APk/CF” (605).
If a shock test is using MIL-STD-810G limits, VibrationVIEW will keep the previous method of computing these parameters but will use an updated method to compute them for MIL-STD-810H.
Download the latest version of VibrationVIEW
VR9500 users with a valid Upgrades and Support Agreement can upgrade to the latest version of VibrationVIEW for free. The demo version is available to any user for free.