Graceful Failure of Laminated Ceramic Tubes produced by Electrophoretic Deposition 1917 2000 1750 E99 1250 0 Cummulative deposition time(min (mm) Fig 3. Calculated(solid line)and experimental ( dots)cumula- ig. 4. Example of a load-displacement diagram recorded tive Sic layer thickness versus cumulative deposition time during a diametral compression test on a laminated ring(dots) After 9 SiC layers the SiC suspension was replaced by a new Sic and calculated overlay (solid line)showing that the slope suspension whilst the deposition experiment was continue changes due to failure can be reproduced accurately if the proposed failure mechanism is used for calculation diagram is of the saw-tooth type typical for lami The relations between the displacement, applied nates: as a Sic layer fails, the crack is deflected into force and stress can be derived by combining the the graphite interlayer. The rest of the ring can solution for an O-ring and a C-ring. The maxin continue to carry load until all SiC layers have tensile stress in an O-ring is related to the applied failed one by one. As a result the work to failur force by: 2 increased and a graceful failure is obtained. The deflection of cracks at the graphite interlayers is very apparent in the photograph of a sample after failure Whilst rather complete descriptions of the bel y+ro iour of laminated ceramic plates in bending -cos e exist, 10 as well as some predictions on their 丌r+h2 behaviour in tensile tests, no description of the behaviour of laminated rings in diametral com vith pression was found in literature. Based on visual r2: the outer radius of the ring(mm); damage observation during the test, stereoscopic r1: the inner radius of the ring(mm); investigation of the damage after the test, and by ro the average radius of the ring(mm)(=(1+r2)/2); taking into account the stress distribution during y: the distance from the average radius(mm) loading of a ring (see below), a more complete description of the failure mechanism is proposed to S: the surface area of the ring(mm2)(=(r2-r1).r); consist of the following sequence of failure events t: the thickness of the ring(mm); (Fig. 6): when the strength of the inner Sic layer is eg: the stress in the 0 direction(MPa, see Fig. 7) reached, it fails and the crack is deflected into the and graphite interlayer. As a result one obtains a thin- er ring and two thin C-rings inside this ring which are still retained by the outer layers. As the strength of the next inner layer of the full ring is reached, 42=1ods=)h(3-2 ro+y again that layer fails and the crack is deflected in the next graphite interlayer, resulting in the formation of a new pair of thin C-rings. Finally the ring will The displacement is related to the force through have been transformed completely in a series of thin C-shaped layers, which will then fail layer by layer The latter because the horizontal plates also retain d he C-rings so that they can still carry load ES2(8x6+h2