ASTM D6484 - Open-Hole Compressive Strength of Polymer Matrix Composite Laminates

ASTM D6484 (Standard Test Method for Open-Hole Compressive Strength of Polymer Matrix Composite Laminates) is an open-hole compression (OHC) testing method that uses a sample with a 6 mm (0.25 inch) diameter circular hole cut in its center. CFRPs offer a number of benefits, including specific strength and high rigidity. However, they lose a substantial amount of their strength when a cutout is made.

ASTM D6468 has two loading methods: Method A and Method B. In Method B the sample is compressed using compression plates located on the ends of the sample and test fixture.

A typical ASTM D6484 test sample is shown in Figure 1. ASTM D6484 Method B test results using a Shimadzu AGX Series Test Machine and TRViewX video extensometer are shown in Table 1. The stress-displacement curves are shown in Figure 2.

Figure 3 shows DIC strain distributions around the hole in the specimen. Strain accumulated at the vertical sides of the open hole (regions 1 and 3), and strain appeared along the axis of compression from those points. The final break occurred at the vertical sides of the hole.

Figure 1: ASTM D6484 Specimen

Figure 2: Stress-Displacement Curves for Compression Test

Figure 3: DIC Analysis Results

Table 1: ASTM D6484 Test Results