Engineering topics

Kolenski, J. D.

Publications and source records attributed to Kolenski, J. D..

4 records

NASA NTRS1994

Viscoplastic response of structures for intense local heating

A thermoviscoplastic finite element method employing the Bodner-Partom constitutve model is used to investigate the response of simplified thermal-structural models to intense local heating. The computational method formulates the problem in rate and advances the solution in time by numerical integration. The thermoviscoplastic response of simplified structures with prescribed temperatures is investigated. With rapid rises of temperature, the nickel alloy structures display initially higher yield stresses due to strain rate effects. As temperatures approach elevated values, yield stress and stiffness degrade rapidly and pronounced plastic deformation occurs.

Thornton, Earl A.↗

NASA NTRS1991

Viscoplastic response of structures for intense local heating

A thermoviscoplastic finite element method employing the Bodner-Partom constitutive model is used to investigate the response of simplified thermal-structural models to intense local heating. With rapid rises of temperature, the nickel alloy structures display initially higher yield stresses due to strain rate effects. As temperatures approach elevated values, yield stress and stiffness degrade rapidly and pronounced plastic deformation occurs.

Thornton, Earl A.↗

NASA NTRS1990

Experimental and computational study of the viscoplastic response of high temperature structures

The first nine months of experimental and computational studies of the thermal-structural behavior of thin panels subjected to localized heating are described. Initial experimental studies have focused on developing an experimental set-up with well-defined thermal-structure boundary conditions. Preliminary tests with a Heldenfels panel have demonstrated out of plane bending (thermal buckling) due to panel initial imperfections. Initial computational studies have focused on: (1) validation of a thermoviscoplastic code to predict thermal stresses in the unbuckled panel, and (2) investigating in-plane stresses for test panels under transient thermal loading. Plans for future research are described.

Thornton, Earl A.↗

NASA NTRS1990

Dynamic effects in thermoviscoplastic structures

An algorithm for three-dimensional thermoviscoplasticity with inertial effects is presented. The algorithm utilizes a unified thermoviscoplastic constitutive model with directional hardening (Bodner-Partom). An example problem is shown in which thermally induced vibrations lead to material yielding at elevated temperatures. Significant dampening caused by inelastic strain is shown to take place in the structure.

Byrom, Ted G.↗