Small Blast Load Generator Tests Using M 9 Propellant

Small Blast Load Generator Tests Using M-9 Propellant

Preliminary Investigation of a Blast Load Generator

The Blast Load Generator is under development at the U.S. Army Engineers Waterways Experimental Station at Vicksburg, Mississippi. It will be used to simulate blast loading for experimental effects studies. Propellant burning inside cylindrical perforated tubes is used to pressurize the Blast Load Generator. Picatinny Arsenal analog personnel were requested to simulate the operation, in order to arrive at the correct propellant charge for generation of given required pressures. Results obtained with a preliminary analog simulation setup gave an approximate picture of the Blast Load Generator. It was established that the over-pressure can be controlled by the vent area, the amount of propellant, and the propellant web. However, since the analog setup is still in its initial stages, several important items must be determined before accurate design of the charges can be undertaken. For example, the thermal coefficients and the effective surface area for heat transfer must be determined. Hence, the results presented in this report can be seen only as approximations and should be used only to indicate trends and guide future tests. (Author).

Development of On-structure Stress Gages

The report describes the development of three types of on-structure stress (OSS) gages (the IF and FS soil-pressure gages and the M-1 airblast gage) based upon the load column principle. The OSS gage design is based upon the assumption (backed by theory and experiment) that if the gage is made much stiffer than the soil, the over-registration of the gage approaches a constant value. A brief discussion of some of the unique problems of measurement of soil pressures is presented. Six OSS gages (four IF, one FS, and one M-1) were statically tested and evaluated with respect to linearity, hysteresis, resolution, thermal sensitivity, and strain sensitivity. Dynamic tests were performed in a laboratory shock tube and blast load simulator facilities. The OSS gages are concluded to be adequate for soil-pressure measurements on certain types of rigid structures and for airblast measurements, even in explosive atmospheres. They successfully measured dynamic gas pressure up to 5,000 psi in the firing tubes of the laboratory blast simulator device. Additional research is recommended to evaluate the gage performance more completely in static and dynamic soil tests. A range of soil types from coarse dry sand to moist fat clays should be investigated. Future research on gages for measuring soil pressures on structures should be concentrated on development of small gages for use with models and thin-walled structures. (Author).