초록 ▼

A standard reference deformation of a composite material containing a flowable phase and compressible inclusions, such as a prepreg, is measured as the deformation whereat the dominant compressive mode of composite deformation changes from that characteristic of compressible inclusion collapse to th

A standard reference deformation of a composite material containing a flowable phase and compressible inclusions, such as a prepreg, is measured as the deformation whereat the dominant compressive mode of composite deformation changes from that characteristic of compressible inclusion collapse to that characteristic of resin flow, termed the optimal consolidation deformation. Establishment of this point permits measurement and correlation of physically significant composite properties. For example, material properties of such composite materials are measured under a compressive loading by an ultrasonic transducer at the optimal consolidation deformation. At this point, normally determined to be the deformation at which the second derivative of compressive displacement falls to about zero, compressible inclusions such as voids are eliminated but the flowable phase has not yet begun to flow significantly so as to change the fractions of the phases. This technique is particularly valuable in ultrasonically measuring properties such as phase fractions of resin matrix prepreg materials wherein the resin has not been cured and readily flows, and wherein there are typically voids that interfere with the measurement of properties.

대표청구항 ▼

A process for measuring a standard reference deformation for a composite material, comprising the steps of: furnishing a specimen of a multiphase material wherein at least one phase is flowable, and which initially contains compressible inclusions within the specimen; compressing the specimen; and d

A process for measuring a standard reference deformation for a composite material, comprising the steps of: furnishing a specimen of a multiphase material wherein at least one phase is flowable, and which initially contains compressible inclusions within the specimen; compressing the specimen; and determining the deformation at which the dominant compressive displacement behavior of the composite material changes from that characteristic of collapse of the compressible inclusions to that characteristic of flow of the flowable phase, this deformation being the standard reference deformation.