Impact Compressive Strength Research Articles

Effect of Fiber Orientation on the Compressive Dynamic Strength of Unidirectionally Reinforced Carbon/Epoxy Composites.

The strength of unidirectionally reinforced carbon/epoxy composites (CFRP) subjected to the compressive impact load was measured by the Split Hopkinson Pressure Bar Method (S. H. P. B. M), then the effect of fiber orientation on the compressive impact strength was investigated. Stress of the specimen, caused by multiple reflected stress waves at its ends in contact with the incident bar and transmitter, was analysed based on one-dimensional stress wave theory. The resulting formulation can be used to evaluate either the linear or nonlinear stress-strain relation. The strength of a specimen of zero-degree fiber is the greatest. The strain of a specimen of 45-degree fiber is the largest. A split fracture parallel to the fiber appeared in the specimen of zero-degree fiber. Inclination of the fracture surface of specimens of 30-, 45- and 60- degree fiber is in alignment with the fiber orientation. Tat of 90 degrees is not. The impact strength is about 80 MPa larger than the static strength. In contrast, the dynamic elongation is smaller than the static elongation.

Compressive Impact Strength of High Temperature Gas-cooled Reactor Graphite

To investigate the effect of strain rate on fracture behavior for coarse grained nuclear graphite, PGX, a hydraulic servo type impact testing machine has been constructed and compressive impact strength test was performed at various strain rates up to more than 100 (1/s). From the results, the following conclusions were derived.(1) Compressive impact strength of graphite increases with increasing of strain rate in the range of 10-3 to 100 (1/s).(2) Compressive impact strength decreases drastically for strain rates more than 100 (1/s).(3) Compressive impact strength dose not depend on specimen volume.

Measurement of the compressive impact strength of concrete using a thin loadcell

This Paper describes a method developed to measure the uniaxial stress-strain response of concrete loaded in compression at the high strain rates which occur during hard impact. Concrete cylinders, nominally 100 mm in diameter and 250 mm long, were impacted with a drop hammer, and transient measurements were recorded with electrical resistance strain gauges used in conjunction with a novel loadcell; the latter incorporating manganin pressure gauges. Particular attention is given to problems encountered with stress measurement when dynamic stress waves are present within the concrete specimen, especially when stress and strain are not measured at the same location.