INVESTIGATION OF THE PRESSURE BEHAVIOR AND REFLECTOR EFFECTS IN AN ELECTROHYDRAULIC PROCESS

• Main Author: Taroepratjeka, Harsono
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/783
• Institution: Institut Teknologi Bandung

High Energy Rate Forming, HERF, is a forming process utilizing the release of intense energy in a very short duration. Electrohydraulic Forming, EHF, is a member of the HERF family. EHF utilizes the effect of electron sparks in a fluid when electrical energy is released from its storage through electrodes-submerged in the fluid. The pressure behavior in an electrohydraulic process under a condition closed to a real-life production was investigated. The effects of the reflecting bodies in the process were studied by means of inserting conical reflectors into the system. The experiment was run in a fractional factorial Split Plot de sign. Analyses of Variance and Multiple Regression were performed to determine the significant effects and the functional relationship between the reflector parameters and the pressure, impulse and energy flux. The pulse patterns of the process consisted of two groups, separated from each other at an elapsed time of about one millisecond. These two groups appeared to have a similar pattern. Each group of pulses spread within a duration of .5 millisecond or less. There were-2 to 9 pulses within the first group. The average pulse duration was 32 microseconds. These pulses were not shock waves. The pressure, impulse and energy flux, except of the first pulses, were stronger at the farthest position from the spark transducer, apparently as the results of the reflection of the chamber base and wall. For the first pulses, the strongest values occurred at the point closest to the spark transducer. <br /> The distance between the source of energy and the reflector, the reflector diameter and the vertical distance between the reflector and the point of measurement, had strong effects on the pressure, impulse and energy flux, in linear functions. The multiple regression equations were developed for the peak pressure of the first, second and third pulses, for the impulse and energy flux for the first, second and third pulses, the total of the first three pulses and the total of all pulses. The use of the reflector could increase as well as reduce the magnitudes of those quantities at a point, as indicated by those equations.