TRANSIENT STRESS DISTRIBUTION IN A RAPIDLY HEATED ROD
>An analytical and experimental investigation of the inertial stresses resulting from very high internal heat generation rates is described. The results show that the amplitude of the thermally induced elastic vibrations in an unrestrained thin rod are dependent upon the ratio of heating time to the fundamental period of oscillation, and that the most severe stress amplitude results from a constant heating rate as compared to an exponential type of input. In the experimental investigation, rapid heating was accomplished by the discharge of a low-inductance capacitor bank (0.1 uh, 2800 Jouies) through the rod. A modified birefringent-coating method was used for observation of the thermally induced oscillations. Utilizing the frozen stress technique of three- dimensional photoelasticity, an initial pattern of interference fringes was introduced into thin strips of birefringent material which were securely bonded to each side of the rod. Strain oscillations were measured by direct observation of the movement of the fringe pattern with a high intensity incident light source, a crossed-circular polariscope, and a high speed framing camera. Interpretation of these measurements required a dynamic calibration and a correction factor for the reinforcing effect of the coating. Oscillations with periods from 35 to 250 mu sec and amplitudes of 9000 psi were measured. The results were in good agreement with the uncoupled thermoelastic theory, and it is concluded that this technique is suitable for transient measurements in the presence of large magnetic fields which normally restrict the use of electronic methods. (auth)
- Research Organization:
- California. Univ., Berkeley. Inst. of Engineering Research
- DOE Contract Number:
- UCX-2285
- NSA Number:
- NSA-17-016260
- OSTI ID:
- 4748420
- Report Number(s):
- HE-150-210; UCRL-13065
- Resource Relation:
- Other Information: For Univ. of California Lawrence Radiation Lab., Livermore. Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- United States
- Language:
- English
Similar Records
Photoelastic analyses of stresses in toroidal magnetic field coils
Photoelastic sphenoscopic analysis of crystals
Related Subjects
CAMERAS
CAPACITORS
COATING
CYLINDERS
EFFICIENCY
ELECTRIC DISCHARGES
ELECTRONICS
GAGES
HEATING
LIGHT
MAGNETIC FIELDS
MATERIALS TESTING
MEASURED VALUES
OPTICAL SYSTEMS
PHOTOELASTICITY
POLARISCOPE
POLARIZATION
RODS
STANDARDS
STRESSES
THERMAL CONDUCTIVITY
THERMAL STRESSES
VARIATIONS
VIBRATIONS