TYPE 8429 (Replaces Type 8730)

BK Connect Shock Response Analysis

Application that computes the shock response spectrum (SRS) from transients in the time domain to determine the damage potential of transient events such as pyroshock

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This BK Connect application computes the shock response spectrum (SRS) of a test object from transient events in the time domain such as pyroshocks or structural impacts. It enables you to determine the damage potential of the transient events and to predict whether the structure will survive such shocks. The SRS calculation converts motion input into single degree of freedom (SDOF) damped oscillator responses. The response amplitudes of the oscillators are plotted as a function of SDOF frequencies to produce the SRS. 

The SRS is calculated in accordance with the ISO 18431–4:2007 standard for shock response analysis. 


  • Determining the structural damage potential from exposure to shock events such as pyroshocks during rocket stage separation
  • Durability testing of shock-sensitive devices such as avionics and guidance equipment 
  • Accurately testing components when a vibration test system cannot generate the time signal of the original shock event due to dynamic limits. Instead shock response synthesis is used, where a new manageable shock pulse is generated with the same SRS as the original shock event
  • Design studies comparing, for example, support structures before and after a weight reduction.
  • Earthquake engineering, to ensure that buildings, bridges and other infrastructures can survive earthquakes


The software includes pre-processing of the shock event. The input data can be viewed before individual shock events are selected for analysis. Before the shock response spectrum calculations themselves, these individual shock events can be corrected for DC offset and drift. The end velocity of the input can be forced to zero as is required in some applications.. There are potentially 45 different options for the user: five shock response spectrum models and nine amplitude calculation outputs (shock instances).


  • Fulfils ISO 18431 - 4:2007 Mechanical vibration and shock - Signal processing - Part 4: Shock-response spectrum analysis
  • Shock response spectrum models: Absolute acceleration, Equivalent Static Acceleration, Pseudo Velocity, Relative Velocity and Relative Displacement
  • Imports acceleration, velocity and displacement transients. Velocity and displacement data are automatically converted to acceleration data before the SRS calculation
  • Ramp-invariant z-transform to reduce errors at high frequencies for pyroshock applications
  • Dynamic oversampling, which reduces bias error and improves the accuracy of peak detection
  • Determination of the velocity change during impact using the pseudo-velocity shock response spectrum model
  • Revealing damage potential from impacts in a pseudo velocity spectrum

The amplitudes of the SRS are derived from these individual SDOF responses by taking the maximum response from the primary shock event (during forced motion), or during the residual response to the event (free response). Most commonly, the overall maximum response is used, which includes both primary and residual responses (maximax).