Pressure-Impulse method

Another graphical method which is sometimes used in the evaluation of SDOF structural elements for blast loading is the Pressure-Impulse, or P-I, method. The P-I method combines both dynamic analysis and design evaluation into a single procedure... 

Active sites created by an electric discharge method were being used for graft copolymerization by Akutin et al. (130). When a solution of a polymer in a suitable monomer is subjected to high voltage electric discharge polymerization of monomer is initiated as a result of the pressure impulses acting on the system. The authors studied the copolymerization of methyl methacrylate onto polyvinyl chloride, and of vinyl chloride onto ethylcellulose. 

The dynamic method sees airflow as a result of the effect of differential pressure on the jet in the gate aperture. Dynamic methods do consider the law of conservation of the impulse in the isolated circuit. According to the type of isolation of the circuit, dynamic methods are divided into methods that determine the trajectory of the jet " and methods that determine the integral flow rate of air through the aperture. This method, due to consideration of... 

Application of the Baker-Strehlow method for evaluating blast effects from a vapor cloud explosion involves defining the energy of the explosion, calculating the scaled distance (/ ), then graphically reading the dimensionless peak pressure (Ps) and dimensionless specific impulse (i ). Equations (4.41) and (4.42) provide the means to calculate incident pressure and impulse based on the dimensionless terms. 

This subject has received little attention in the context of pressure vessel bursts. Pittman (1976) studied it using a two-dimensional numerical code. However, his results are inconclusive, because the number of cases he studied was small and because the grid he used was coarse. Baker et al. (1975) recommend, on the basis of experimental results with high explosives, the use of a method described in detail in Section 6.3.3. That is, multiply the volume of the explosion by 2, read the overpressure and impulse from graphs for firee-air bursts, and multiply them by a factor depending on the range. 

Baker et al. (1975) developed a method, presented below, for predicting blast effects fiom the rupture of gas-filled pressure vessels. They include a method for calculating the overpressure and impulse of blast waves from the rupture of spherical or cylindri-... 

The method presented above is based on the similarity of the blast waves of pressure vessel bursts and high explosives. This similarity holds only at some distance from the explosion. In the near field, the peak overpressure and impulse from a pressure... 

Two independent means, graphical relative pressure methods, are used to obtn EW EV from peak pressure measurements. Two comparable methods obtn these figures of merit from positive impulse data. There is also described a method for detg EW Si EV from an analytical study of positive impulse data... 

The reaction zone of a secondary expl can be subjected to an impulsive rise of pressure leading to deton within tens of microseconds by a technique termed ACP (augmented by collision pressure). This ACP method is claimed to have practical advantages of simplicity and reliability when compared with expl bridgewires and the known procedures for burning to deton. It has been applied to RDX (Ref 45a)... 

Gibson method. The mean velocity in a penstock leading from a reservoir can be determined by rapidly closing a valve at the lower end and recording a pressure-time diagram at a point just upstream from the valve. The principle that impulse equals change of momentum can be applied to the mass of liquid between the reservoir and the point of measurement. The impulse is given by the area under the recorded pressuretime curve, and from this the initial velocity can be determined [10]. 

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