Research On Dynamic Uncertainty Of The Shock Wave Overpressure Test System

Shock overpressure test is one of the important methods of measuring explosive power ofweapons, and the related parameters’ accurately test plays a vital function for weaponsdevelopment. Now uncertainty is generally used to describe the accuracy of measuring result.At present, static uncertainty theory have developed a lot, but the peak value of shock wavesignal in explosion field is very large and the peak time is extraordinarily short, whichpertains to dynamic test category, the dynamics and time variation of which determined thatdynamic uncertainty has a greater complexity than static uncertainty. Now dynamicuncertainty theory is at the initial stage of exploration. Based on the existing uncertaintytheory, the paper analyzes and calculates the uncertainty of test system and mainly has astudy on the following aspects:(1)Based on lots of related domestic and overseas literatures, the paper analyzes theproduction, features and parameters of shock wave signal, and expounds the relateduncertainty theory and evaluation method, which lay a theory foundation for the calculationof the test system’s dynamic uncertainty.(2)The high bandwidth of explosion shock wave signal determines the high requirementfor the pressure sensor and the dynamic characteristics of which is a critical link to ensure thedata accuracy. Shock tube calibration experiment is carried on seven transducers, includingAmerican PCB,ENDEVCO and domestic corporation, to get the time and frequency domainof dynamic performance index.(3)According to the system’s transfer chain accuracy model, test system’s uncertaintymodel is built. Then the uncertainty of each module of test system is calculated, containingthe sensor part ,filter part and ADC part. Then the uncertainty of the whole test system isevaluated. (4)To ensure the accuracy and reliability of the test, it is needed to have a dynamicsensitivity calibration of test system. Based on the principle of dynamic sensitivity calibration,the uncertainty model of the dynamic sensitivity is established. Then it is calculated that thesingle calibration uncertainty involving the shock tube calibration device and the readinguncertainty and the curve fitting uncertainty of repeat calibration. At last, the syntheticuncertainty of dynamic sensitivity is given.