Tests fracture

Fig. 11. Fracture stress versus crack depth for small flaw fracture tests in IG-11 graphite.

Johansson, S., "Fracture Testing of Silicon Microelements In Situ in a Scanning Electron Microscope, 7. Appl. Phys., Vol. 63,1988,pp. 4799 808. 

Fracture strength, of vitreous silica, 22 428 Fracture tests, 1 514 Fracture toughness ceramics, 5 619-623 of silicon carbide, 22 528t of vitreous silica, 22 429 Fracture toughness tests, 10 427 Fracture toughness values... 

In many fracture tests, a splitting method was employed. Figures 8 to 10 schematically indicate three of the arrangements used. In Fig. 8, a slice, h cm thick, is separated from the rest of the solid by pushing in a wedge which may be as thin as 0.01 cm but may also be more robust and have one of various shapes also the part broken off may be as thick as the remainder. In Fig. 9, a plate, 2h cm thick and w cm wide, is split in the middle to the depth c cm, and the force /required to extend the fissure is measured. Figure 10 shows peeling a ribbon, h cm thick, is peeled off the main body of an identical solid. 

Fig. 3.30. Schematic illustrations of Mode I interlaminar fracture test specimens (a) DCB specimen (b)...

The pure mode II interlaminar fracture testing can be performed using both the end notched flexure (ENF) specimen (Russell and Street, 1984, 1985) and the end loaded split (ELS) specimen (Corleto and Bradley, 1987 Prel et al.. 1989) (Fig 3.32). 

Fig. 3.33. CLS specimen for mixed mode interlaminar fracture tests.

Davies, P. and Roulin. A. (1989). A standard for interlaminar fracture testing of composites. In Proc. ECCM 3, Developments in the Science and Technology of Composite Materials. (A.R. Bunsell, P. Lamicq and A. Massiah eds.), Elsevier Appl. Sci., London, pp. 419-424. 

Davies, P. Kausch, H.H., Williams, J.G. and 29 other researchers (1992). Round-robin interlaminar fracture testing of carbon fiber reinforced epoxy and PEEK composites. Composites Sci. Technol. 43, 129-136. 

Mandell 3.F., Darwish, A.Y. and McGarry F.3. (1981). Fracture testing of injection-molded glass and carbon fiber-reinforced thermoplastics. In Testing Methods and Design Allowable for Fibrous Composites, ASTM STP 734 (C.C. Chamis ed.), ASTM, Philadelphia, PA, pp. 73 90. 

Properties of Manganese. Break up the manganese bead with a pestle in a steel mortar or with a hammer. Give attention to the brittleness of the metal, note its colour in a fresh fracture, test it with a magnet, see how it reacts with water, an alkali solution, and also with dilute and concentrated solutions of hydrochloric, sulphuric, and nitric acids (in the cold and with heating). Write the equations of the reactions. 

Results. The first explosive fracturing test detonated 100 qt of NG1 displaced into the formation from well 3 at a depth interval from 70 to 74 ft. Following detonations in wells 3 and 4, fracture intervals in the wellbores connecting the injection well 3 and other wells were determined by airflow measuerments. 

In general, hydraulic fracturing with sand propping provided adequate void space for emplacement of the NG1 in these explosive-fracturing tests in the oil shale. Explosive fracturing caused significant increases in fracture permeability when a sufficient NG1 charge was detonated. 

The final explosive-fracturing test performed on this site was a simultaneous shot detonated in the wells of the five-spot pattern. Wire-line measurements were obtained to determine total depth, and caliper logs were run to determine wellbore enlargement from which to calculate the amount of TNT to fill each well. Water was swabbed and bailed... 

Results of explosive fracturing tests in oil shale show that NG1 will detonate and that the explosion will propagate in water-filled natural fractures and sand-propped, hydraulically induced fractures in oil shale. The shale was fragmented by this method, and a successful underground retorting experiment to recover shale oil was performed. 

The fracture properties of foods have been extensively studied and comprehensive reviews (64 and references therein) exist that address testing and application of fracture data in the food industry. As mentioned earlier, in the food industry compression tests are viewed also as fracture tests and the yield stress is often regarded as the fracture stress. However, in this review, the discussion is confined to only those types of fracture tests that lead to estimates of the fracture toughness and not the yield stress. The fracture toughness tests are relatively recent in the food industry. 

A number of different fracture toughness tests have been applied to foods including, the microtome test (65), the wedge fracture test (66-68) and tension tests (69). The 3-point bend test was applied by Charalmabides et al (70) in testing Cheddar cheeses. 

Apart from the Microtome or the Wedge fracture test, a notch is introduced... 

J.F.V. Vincent, G. Jeronimidis, A.A. Khan and H. Lutyen, The Wedge Fracture Test, A New Method for Measurement of Food Texture, J. Texture Studies, 22 45-57 (1991). 

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