Beck, Peter | Search NASA

DOE OSTI2024

Ring Pull Strain Analysis

Ring Pull Strain Analysis (RPSA) is a framework for analysis of Digital Image Correlation (DIC) data of gaugeless ring pull testing. It is meant for analysis of rings cut from tube cross sections and pulled in a displacement-controlled tensile test. This code takes load frame data, images take during testing, and csv files from the DIC analysis of those images and allows the user to analyze and plot data from the test. Some important features of the software include getting the strain values as a function of radial distance and angle, plotting of the strain around the ring, and stress-strain analysis of the load frame data. Additional capability is included with Ring Pull Coating Analysis (RPCA, also part of the software). Additional images are taken of samples with an outer coating and are used to correlate failure of the coating with strain values measured with DIC.

Beck, Peter↗

DOE OSTI2022

Ring Pull Strain Analysis

Ring Pull Strain Analysis (RPSA) is a framework for analysis of Digital Image Correlation (DIC) data of gaugeless ring pull testing. It is meant for analysis of rings cut from tube cross sections and pulled in a displacement-controlled tensile test. This code takes load frame data, images take during testing, and csv files from the DIC analysis of those images and allows the user to analyze and plot data from the test. Some important features of the software include getting the strain values as a function of radial distance and angle, plotting of the strain around the ring, and stress-strain analysis of the load frame data.

Beck, Peter↗

DOE OSTI2017

Effect of Combustion Products on Detonation Velocities

Pressure gain combustion has received increased interest in recent years because of the potential for increased thermodynamic efficiencies in propulsion and power generation applications. In pressure gain devices, mixing of fuel and oxidizer with combustion products can occur in the combustion chamber as the reactants are injected and the exhaust products are purged. Most research, however, considers only fresh reactants. This is significant because mixing can result in decreased detonation velocities. Laminar flame speed calculations show that dilution with combustion products can reduce the flame speed as a consequence of both dilution and chemistry effects. The objective of this study is to identify the effects of dilution with combustion products on detonation velocities, expanding on the results for laminar flame speed calculations. Experiments were performed using a pulse detonation engine instrumented with photodiodes to measure detonation velocities. Sonic orifices were used to meter mass flow rates of fuel (C 3 H 8 ), oxidizer (N 2 O), and combustion products (CO 2 ) or inert diluents (N 2 ). The experiments were performed such that the sensible enthalpy of the diluents was matched, thus observed velocity sensitivities indicate a chemical kinetic effect. The data indicates that non-inert diluents demonstrate a suppression in detonation velocities resulting from chemical kinetic effects. Specifically, testing with CO 2 showed a significant velocity deficit when compared to inert N 2 .

Bean, Derek↗