An evaluation of the sandwich beam compression test method for compositesThe sandwich beam in a four-point bending compressive test method for advanced composites is evaluated. Young's modulus and Poisson's ratio were obtained for graphite/polyimide beam specimens tested at 117 K, room temperature, and 589 K. Tensile elastic properties obtained from the specimens were assumed to be equal to the compressive elastic properties and were used in the analysis. Strain gages were used to record strain data. A three-dimensional finite-element model was used to examine the effects of the honeycomb core on measured composite mechanical properties. Results of the analysis led to the following conclusions: (1) a near uniaxial compressive stress state existed in the top cover and essentially all the compressive load was carried by the top cover; (2) laminate orientation, test temperature, and type of honeycomb core material were shown to affect the type of beam failure; and (3) the test method can be used to obtain compressive elastic constants over the temperature range 117 to 589 K.
Document ID
19810063405
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Shuart, M. J. (NASA Langley Research Center Materials Div., Hampton, VA, United States)
Date Acquired
August 11, 2013
Publication Date
January 1, 1981
Subject Category
Composite Materials
Meeting Information
Meeting: Symposium on Test methods and design allowables for fibrous composites