Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Shock testing”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Digital control of high-intensity acoustic testing

Three systems for the control of acoustic testing are compared: a hybrid digital/analog system, a digital vibration system, and the same digital vibration system modified by a software change. The hybrid system was constructed to control the 1/3-octaves from 50 to 1000 Hz. The vibration system was equipped with programs for sine and random vibration tests, shock analysis and synthesis, and signal analysis. For the modified vibration system, the random-vibration control program of the unmodified unit was changed so that acoustic tests could be performed. The performance of the three systems is compared by conducting probability-density and time-history analyses of the proposed test spectrum for the Mariner Jupiter/Saturn 1977 program. The results of the analyses show that the hybrid and modified vibration systems perform almost equally, but the modified vibration system is easier to use and produces better test documentation.

Slusser, R. A.↗
NASA NTRS1999

Thermal-Mechanical Stability of Single Crystal Oxide Refractive Concentrators for High-Temperature Solar Thermal Propulsion

Single crystal oxides such as yttria-stabilized zirconia (Y2O3-ZrO2), yttrium aluminum garnet (Y3Al5O12, or YAG), magnesium oxide (MgO) and sapphire (Al2O3) are candidate refractive secondary concentrator materials for high temperature solar propulsion applications. However, thermo-mechanical reliability of these components in severe thermal environments during the space mission sun/shade transition is of great concern. Simulated mission tests are important for evaluating these candidate oxide materials under a variety of transient and steady-state heat flux conditions, and thus provide vital information for the component design. In this paper, a controlled heat flux thermal shock test approach is established for the single crystal oxide materials using a 3.0 kW continuous wave CO2 laser, with a wavelength 10.6 micron. Thermal fracture behavior and failure mechanisms of these oxide materials are investigated and critical temperature gradients are determined under various temperature and heating conditions. The test results show that single crystal sapphire is able to sustain the highest temperature gradient and heating-cooling rate, and thus exhibit the best thermal shock resistance, as compared to the yttria-stabilized zirconia, yttrium aluminum garnet, and magnesium oxide.

Zhu, Dongming↗
NASA NTRS1999

Thermal-Mechanical Stability of Single Crystal Oxide Refractive Concentrators for High-Temperature Solar Thermal Propulsion

Single crystal oxides such as yttria-stabilized zirconia (Y2O3-ZrO2), yttrium aluminum garnet (Y3Al5O12, or YAG), magnesium oxide (MgO) and sapphire (Al2O3) are candidate refractive secondary concentrator materials for high temperature solar propulsion applications. However, thermo-mechanical reliability of these components in severe thermal environments during the space mission sun/shade transition is of great concern. Simulated mission tests are important for evaluating these candidate oxide materials under a variety of transient and steady-state heat flux conditions, and thus provide vital information for the component design. In this paper, a controlled heat flux thermal shock test approach is established for the single crystal oxide materials using a 3.0 kW continuous wave CO2 laser, with a wavelength 10.6 micron. Thermal fracture behavior and failure mechanisms of these oxide materials are investigated and critical temperature gradients are determined under various temperature and heating conditions. The test results show that single crystal sapphire is able to sustain the highest temperature gradient and heating-cooling rate, and thus exhibit the best thermal shock resistance, as compared to the yttria-stabilized zirconia, yttrium aluminum garnet and magnesium oxide.

Zhu, Dongming↗
NASA NTRS2011

Microcoil Spring Interconnects for Ceramic Grid Array Integrated Circuits

As integrated circuit miniaturization trends continue, they drive the need for smaller higher input/output (I/O) packages. Hermetically sealed ceramic area array parts are the package of choice by the space community for high reliability space flight electronic hardware. Unfortunately, the coefficient of thermal expansion mismatch between the ceramic area array package and the epoxy glass printed wiring board limits the life of the interconnecting solder joint. This work presents the results of an investigation by Marshall Space Flight Center into a method to increase the life of this second level interconnection by the use of compliant microcoil springs. The design of the spring and its attachment process are presented along with thermal cycling results of microcoil springs (MCS) compared with state-of-the-art ball and column interconnections. Vibration testing has been conducted on MCS and high lead column parts. Radio frequency simulation and measurements have been made and the MCS has been modeled and a stress analysis performed. Thermal cycling and vibration testing have shown MCS interconnects to be significantly more reliable than solder columns. Also, MCS interconnects are less prone to handling damage than solder columns. Future work that includes shock testing, incorporation into a digital signal processor board, and process evaluation of expansion from a 400 I/O device to a device with over 1,100 I/O is identified.

Strickland, S. M.↗
NASA NTRS1989

Effects Of Pyrotechnically Generated Shocks

Research program provides better understanding of pyrotechnic phenomenon for design purposes. Evaluating potential for damage to spacecraft by activation of pyrotechnic mechanisms, pyrotechnic-shock tests conducted on three configurations: pin pullers on orthogonal double Hopkinson bar arrangement; pin pullers on mockup of Halogen Occultation Experiment (HALOE) structure; and section of separation joint on single Hopkinson bar. Strains and accelerations measured. Strains converted to output stresses, forces, and moments. Acceleration shock-response spectra obtained for both acceleration and force signals. Results of research useful to designers in making comparison and evaluation tests before committing to costly spacecraft hardware.

Bement, Laurence J.↗
NASA NTRS1988

Pyro shock simulation: Experience with the MIPS simulator

The Mechanical Impulse Pyro Shock (MIPS) Simulator at GE Astro Space Division is one version of a design that is in limited use throughout the aerospace industry, and is typically used for component shock testing at levels up to 10,000 response g's. Modifications to the force imput, table and component boundary conditions have allowed a range of test conditions to be achieved. Twelve different designs of components with weights up to 23 Kg are in the process or have completed qualification testing in the Dynamic Simulation Lab at GE in Valley Forge, Pa. A summary of the experience gained through the use of this simulator is presented as well as examples of shock experiments that can be readily simulated at the GE Astro MIPS facility.

Dwyer, Thomas J.↗
NASA NTRS1999

Thermal Mechanical Stability of Single-Crystal-Oxide Refractive Concentrators Evaluated for High-Temperature Solar-Thermal Propulsion

Recently, refractive secondary solar concentrator systems were developed for solar thermal power and propulsion (ref. 1). Single-crystal oxides-such as yttria-stabilized zirconia (Y2O3-ZrO2), yttrium aluminum garnet (Y3Al5O12, or YAG), magnesium oxide (MgO), and sapphire (Al2O3)-are candidate refractive secondary concentrator materials. However, the refractive concentrator system will experience high-temperature thermal cycling in the solar thermal engine during the sun/shade transition of a space mission. The thermal mechanical reliability of these components in severe thermal environments is of great concern. Simulated mission tests are important for evaluating these candidate oxide materials under a variety of transient and steady-state heat flux conditions. In this research at the NASA Lewis Research Center, a controlled heat flux test approach was developed for investigating the thermal mechanical stability of the candidate oxide. This approach used a 3.0-kW continuous-wave (wavelength, 10.6 mm) carbon dioxide (CO2) laser (ref. 2). The CO2 laser is especially well-suited for single-crystal thermal shock tests because it can directly deliver well-characterized heat energy to the oxide surfaces. Since the oxides are opaque at the 10.6-mm wavelength of the laser beam, the light energy is absorbed at the surfaces rather than transmitting into the crystals, and thus generates the required temperature gradients within the specimens. The following figure is a schematic diagram of the test rig.

Jacobson, Nathan S.↗
NASA NTRS1987

Measurement, data analysis and prediction of pyrotechnic shock from pin-pullers and separation joints

To evaluate the potential for spacecraft damage caused by activation of pyrotechnic mechanisms, pyrotechnic shock tests were conducted on three configurations: pin-pullers on an orthogonal double Hopkinson bar arrangement, pin-pullers on a mock-up of the HALOE (Halogen Occultation Experiment) structure, and a section of separation joint on a single Hopkinson bar. Strains and accelerations were measured. The strains were converted to output stresses, forces and moments. Acceleration shock response spectra are presented for both acceleration- and force-time signals. The devices were attached to the Hopkinson bars with adaptors, which are typical of attachments used in practice. In order to predict the effect of the adaptors, finite element models of the adaptor-bar combinations were analyzed and results are presented with regard to grid size, time interval, and frequency range required to predict the response to pulses of 10 and 100 microsecond duration.

Evans, Maria J.↗
NASA NTRS1994

Thermal Testing of High Performance: Thermal Barrier Coatings for Turbine Blades

A 350 micron thick 7 wt.% Y 2 O 3 -ZrO 2 (7YSZ) ceramic Thermal Barrier Coating (TBC) was manufactured in an argon atmosphere and with a strictly controlled substrate temperature on flat IN 600 samples and on IN 100 aircraft turbine blades. This new atmosphere and temperature controlled spraying (ATCS) allows the reduction of the residual stresses and an improvement in the microstructure and in the mechanical properties of the coating. The good performance of these new TBC's was assessed in thermal fatigue and in thermal shock tests carried out in air at 1100°C and at 1280°C respectively. The oxidation rate of the metal-ceramic interface was measured at 1100°C. Failure of the TBC's was induced only by the deterioration (like oxidation, cracking, ...) of the uncoated parts of the samples, as testing temperature was too severe for the base metals. Spalling was thereafter driven by compressive stresses near the aluminum oxide layer at the metal-ceramic interface. The results of these tests underline the good quality of the ceramic coating manufactured by the new ATCS technology.

L Bertamini↗
NASA NTRS2018

Improved Pyrotechnic Shock Scaling Method Based on Shock Response Spectrum and Statistical Energy Analysis

It has been more than forty years since the pyrotechnic shock scaling method was introduced. The scaling method estimates the attenuation of the Shock Response Spectrum (SRS) based on the distance from the source, structural configurations, types of structural joints and interfaces, and intervening structure [1]. The method has been successfully used in the spacecraft community countless times and still is frequently used to develop pyrotechnic shock requirements at various levels of assembly of a spacecraft. However, since the method was derived empirically from a limited set of shock test data [2], the aerospace community has been looking for an alternative approach. In this paper, a computational scaling method based on Statistical Energy Analysis (SEA) is re-visited. SEA is traditionally used as a method for investigating the diffusion of acoustic and vibratory energies of a system at steady-state [3]. Previously, an approach using the SRS as an acceleration constraint condition to the SEA model was introduced to estimate the attenuation from a shock source [4,5]. In the current investigation, additional examples are provided to further validate the approach. In addition, responses in the time domain are produced by the Local Modal Phase Reconstruction (LMPR) approach which was recently introduced to the community [6].

Fernandez, Juan P.↗
NASA NTRS1992

A cryogenic multichannel electronically scanned pressure module

Consideration is given to a cryogenic multichannel electronically scanned pressure (ESP) module developed and tested over an extended temperature span from -184 to +50 C and a pressure range of 0 to 5 psig. The ESP module consists of 32 pressure sensor dice, four analog 8 differential-input multiplexers, and an amplifier circuit, all of which are packaged in a physical volume of 2 x 1 x 5/8 in with 32 pressure and two reference ports. Maximum nonrepeatability is measured at 0.21 percent of full-scale output. The ESP modules have performed consistently well over 15 times over the above temperature range and continue to work without any sign of degradation. These sensors are also immune to repeated thermal shock tests over a temperature change of 220 C/sec.

Shams, Qamar A.↗
NASA NTRS1968

Science data systems

Shock tests on Mariner Venus 67 prototype data automation subsystems to evaluate multilayer laminate packaging

Source record↗
NASA NTRS1971

Vibration manual

Guidelines of the methods and applications used in vibration technology at the MSFC are presented. The purpose of the guidelines is to provide a practical tool for coordination and understanding between industry and government groups concerned with vibration of systems and equipments. Topics covered include measuring, reducing, analyzing, and methods for obtaining simulated environments and formulating vibration specifications. Methods for vibration and shock testing, theoretical aspects of data processing, vibration response analysis, and techniques of designing for vibration are also presented.

Green, C.↗