skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Characterization of Shear Properties for APO/MBI Syntactic Foam

Abstract

Triaxial compression testing is a means for mechanical characterization of a material. A unique feature of the triaxial compression test is the application of two different magnitudes of compressive pressures on the material simultaneously. The material behavior under these different compressive pressures can be monitored over time. Several important characteristics of the material, such as stress yield values and the shear failure envelope may then be determined. Also mechanical properties such as Poisson’s ratio, Young’s modulus and bulk modulus can be determined from the triaxial compression test. The triaxial compression test was employed in this investigation to characterize the shear behavior, shear failure envelope, and mechanical properties of a syntactic foam. Los Alamos National Laboratory (LANL) supplied a total of 36 samples of APO-BMI syntactic foam to the University of New Mexico, Department of Civil Engineering for testing between December 2003 and May 2004. Each sample had a diameter of 1.395±0.005 in. (3.543±0.013cm.) and a length of 2.796±0.004 in. (7.102±0.010 cm.). The samples had an average density of 0.295 g/cm3. Additional information about the material tested in this investigation can be found in the “Specimen Description” section contained in Chapter 1. The nomenclatures used in this study is presented inmore » Chapter 1. In addition to designing and implementing triaxial compression tests capable of up to 2,000 psi. confining pressure (minor principal stress) and roughly 13,000 psi. in axial pressure (major principal stress), a pure tension test was designed and conducted on the foam material. The purpose of this pure tension test was to obtain maximum tensile stress values to enhance the characterization of the shear envelope in the stress space. The sampling procedure and specimen preparation for a standard test can be found in the American Society for Testing Materials (ASTM) D 5379/ D 5379 – 93. The above tests mentioned and their procedures are discussed in Chapter 2. Chapter 2 contains the types of tests performed and the apparatus used for testing the material. Chapter 2 also has a brief explanation of the equipment and the procedures used for conducting the tests. In Chapter 3, the material characteristics and mechanical properties obtained from the tests are described; composite plots of deviatoric vs. mean stress and deviatoric stress vs. longitudinal strain are also included. The plots of deviatoric stress vs. mean stress clearly identify the shear envelope for the material. Chapter 4 summarizes the vital information obtained from the tests and the conclusions made. All the necessary plots and the data generated during the testing have been included in the Appendix. The information in the appendix includes plots of: Strain vs. Time, Stress vs. Time, Stress vs. Strain, Mean Stress vs. Volumetric Strain, Lateral Strain vs. Longitudinal Strain, and q vs. p. Bulk modulus, Poisson’s ratio, and Young’s modulus are displayed in the appropriate plots in each appendix.« less

Authors:
 [1];  [2];  [1];  [1];  [1]
  1. Univ. of New Mexico, Albuquerque, NM (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1414077
Report Number(s):
LA-UR-17-31268
DOE Contract Number:
AC52-06NA25396
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; triaxial testing

Citation Formats

Reser, Patrick M., Lewis, Matthew W., Clark, Jarod, Ahuja, Nishant, and Lenke, Lary R.. Characterization of Shear Properties for APO/MBI Syntactic Foam. United States: N. p., 2017. Web. doi:10.2172/1414077.
Reser, Patrick M., Lewis, Matthew W., Clark, Jarod, Ahuja, Nishant, & Lenke, Lary R.. Characterization of Shear Properties for APO/MBI Syntactic Foam. United States. doi:10.2172/1414077.
Reser, Patrick M., Lewis, Matthew W., Clark, Jarod, Ahuja, Nishant, and Lenke, Lary R.. 2017. "Characterization of Shear Properties for APO/MBI Syntactic Foam". United States. doi:10.2172/1414077. https://www.osti.gov/servlets/purl/1414077.
@article{osti_1414077,
title = {Characterization of Shear Properties for APO/MBI Syntactic Foam},
author = {Reser, Patrick M. and Lewis, Matthew W. and Clark, Jarod and Ahuja, Nishant and Lenke, Lary R.},
abstractNote = {Triaxial compression testing is a means for mechanical characterization of a material. A unique feature of the triaxial compression test is the application of two different magnitudes of compressive pressures on the material simultaneously. The material behavior under these different compressive pressures can be monitored over time. Several important characteristics of the material, such as stress yield values and the shear failure envelope may then be determined. Also mechanical properties such as Poisson’s ratio, Young’s modulus and bulk modulus can be determined from the triaxial compression test. The triaxial compression test was employed in this investigation to characterize the shear behavior, shear failure envelope, and mechanical properties of a syntactic foam. Los Alamos National Laboratory (LANL) supplied a total of 36 samples of APO-BMI syntactic foam to the University of New Mexico, Department of Civil Engineering for testing between December 2003 and May 2004. Each sample had a diameter of 1.395±0.005 in. (3.543±0.013cm.) and a length of 2.796±0.004 in. (7.102±0.010 cm.). The samples had an average density of 0.295 g/cm3. Additional information about the material tested in this investigation can be found in the “Specimen Description” section contained in Chapter 1. The nomenclatures used in this study is presented in Chapter 1. In addition to designing and implementing triaxial compression tests capable of up to 2,000 psi. confining pressure (minor principal stress) and roughly 13,000 psi. in axial pressure (major principal stress), a pure tension test was designed and conducted on the foam material. The purpose of this pure tension test was to obtain maximum tensile stress values to enhance the characterization of the shear envelope in the stress space. The sampling procedure and specimen preparation for a standard test can be found in the American Society for Testing Materials (ASTM) D 5379/ D 5379 – 93. The above tests mentioned and their procedures are discussed in Chapter 2. Chapter 2 contains the types of tests performed and the apparatus used for testing the material. Chapter 2 also has a brief explanation of the equipment and the procedures used for conducting the tests. In Chapter 3, the material characteristics and mechanical properties obtained from the tests are described; composite plots of deviatoric vs. mean stress and deviatoric stress vs. longitudinal strain are also included. The plots of deviatoric stress vs. mean stress clearly identify the shear envelope for the material. Chapter 4 summarizes the vital information obtained from the tests and the conclusions made. All the necessary plots and the data generated during the testing have been included in the Appendix. The information in the appendix includes plots of: Strain vs. Time, Stress vs. Time, Stress vs. Strain, Mean Stress vs. Volumetric Strain, Lateral Strain vs. Longitudinal Strain, and q vs. p. Bulk modulus, Poisson’s ratio, and Young’s modulus are displayed in the appropriate plots in each appendix.},
doi = {10.2172/1414077},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month =
}

Technical Report:

Save / Share:
  • This project was started early in the redevelopment of the carbon syntactic foam. The new mixture of carbon microballoons with the APO-BMI resin had not been fully characterized, but that was the actual purpose of this effort. During the forming of the billets for these tests, a problem began to surface; but full understanding of the problem did not evolve until samples were cured and tests were conducted. Material compressive strengths varied between 200 and 990 psi where anything below 700 was rejected. The cure cycle was adjusted in an iterative manner in an attempt to maximize the material strength.more » The result of this effort was that the material strength was almost doubled and was achieving strengths of 1,500 psi toward the end of the parts produced. As a consequence, some of the strength tests actually run and reported in the text of this report may not reflect data that would be obtained today. The material strength was continuously being improved over the entire year. A complete series of compression test data is reported, but subsequent tensile and flexural strength tests were not repeated. At a time when it is considered that there are no further changes to be incorporated, a repeat of these tests would be warranted. Some development remains to be done on the carbon microballoon material. Improved carbon material is now available and its effect of the material strength should be evaluated.« less
  • Syntactic foam encapsulation protects sensitive components. The energy mitigated by the foam is calculated with numerical simulations. The properties of a syntactic foam consisting of a mixture of an epoxy-rubber adduct and glass microballoons are obtained from published literature and test results. The conditions and outcomes of the tests are discussed. The method for converting published properties and test results to input for finite element models is described. Simulations of the test conditions are performed to validate the inputs.
  • Polyurethane foam, having a density of 64-kg/cu m, was tested at 295, 111, 76, and 4 K. The material properties reported are Young's modulus, proportional limit, yield strength (at 0.2% offset), tensile, shear, and compressive strengths, and elongation (elastic and plastic). To perform these tests, a unique apparatus was developed. This apparatus permits tension, compression, and shear testing of materials at any temperature ranging from 295 to 1.8 K. Strain is measured with a concentric, overlapping-cylinder capacitance extensometer that is highly sensitive and linear in output.
  • A manufacturing process developed for parylene coating syntactic parts has resulted in several improvements. Thin edges have been strengthened, which minimizes breakage during the manufacturing process and subsequent assembly; part and surface toughness has been improved; the coefficient of friction during assembly has been reduced; and the bonding of the pads, shoehorn, and clips has been enhanced. Improvements in the tensile strength and flexural strength of the syntactic composite as a result of the coating are discussed, and coated parts and deposited films produced by laboratory and production coaters are compared.