Microfracture behaviour of composite resins containing irregular-shaped fillers was understood by filler morphology observation, fracture toughness test and acoustic emission (AE) detecting method. The fracture toughness (KIC) was obtained by using single edge notched specimens. AE, the elastic wave due to the debonding of filler from the resin matrix or the fracture of filler itself, was detected during fracture toughness test. The reasons for the different fracture toughness values of composite resin, in spite of having almost the same morphology and filler content, were understood by the results of fracture surface finding and AE releasing behaviour during fracture toughness test.
Machining accuracy is directly influenced by the quasi-static errors of a machine tool. Since machine errors have a direct effect upon both the surface finish and geometric shape of the finished workpiece, it is imperative to measure the machine errors and to compensate for them. A laser measurement system to identify geometric errors of a machine tool has disadvantages, such as a high cost, a long calibration time and the usage of a volumetric error synthesis model. In this study, we proposed a novel analysis of the geometric errors of a machine tool using a ball bar test without using a complicated error synthesis model. Also, a statistical analysis method was employed to derive geometric errors using a hemispherical helix ball bar test. According to the experimental result, we observed that geometric errors of the vertical machining centre were compensated by 88%.
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