Radial Fractures

Fig. 9,20 Spiral bevel ring gear assembly from the forward transmission gear box of Boeing Vertol 234-LR (Chinook) aircraft registration G-BWFC which crashed into the sea off the Shetland Isles in 1986. Note the peripheral and radial fractures in the gear, which appeared to be responsible for the crash. There was evidence of fretting and galvanic corrosion which may have been responsible for initiation of the fracture sequence...

B. The direct identification of such microscopic fracture modes as transgranular cleavage, radial fracture, intergranular separation or ductile dimpled rupture, was shown to be considerably more dependable by SEM than by OM... 

By selecting the block large enough that it was not ruptured by the deton of an axial chge, they found (on sectioning the block) a network of radial fractures that neither began at the slightly deformed shot hole, nor the cylindrical surface of the block. 

The collapse of the cavity causes stress modification (known as readjustments) in the medium around the chimney, and can generate secondary fracturing. This fracturing can take the form of either vertical fractures, roughly parallel to the walls of the chimney, or radial fractures caused by the subsidence of the geological layers near the chimney. 

Tectonic breaching within the GEA is mostly related to Cretaceous to Tertiary compressional or tran-spressional deformation and is manifested by two processes. Firstly, extension occurs above the neutral surface of inversion folds (Fig. 8a), thereby creating a pattern of radial tension fractures, extending upwards from the seal into the overlying section. Radial fractures will not form below the neutral surface of the fold limb which is in compression. As a consequence, reservoir objectives lying above or close to the neu-... 

Fig. 8. Schematic illustration of tectonic breaching for (a) structural inversions and (b) footwall fault blocks. Tectonic breaching within inversions is caused by radial fractures and wrench faults. It is also possible that tectonic breaching may be caused by the re-activation of normal faults.

Kopylov P, Aspenbeeg P, Yuan X and Ryd L (2001) Radiostereometric analysis of distal radial fracture displacement during treatment a randomized study comparing Norian SRS and external fixation in 23 patients. Acta Orthop Scand 72 57-61. 

A short radial fracture develops, propagating to the point where p = Oe. 

Cassidy, C., Jupiter, J.B., Cohen, M., Delli-Santi, M., Fennell, C., Leinberry, C., Husband, J., Ladd, A., Seitz, W.R., Constanz, B. 2003. Norian SRS cement compared with conventional fixation in distal radial fractures. A randomized study. J Bone Joint Surg Am.S5-A(ll), 2127-2137. 

Kopylov, P., Runnqvist, K., Jonsson, K., and Aspenberg, P. (1999), Norian SRS versus external fixation in redisplaced distal radial fractures A randomized study in 40 patients, Acta Orthop. Scand. 70(l) l-5. 

Galeazzi fracture patterns occur where there is a fracture of the distal radius associated with disruption of the distal radioulnar joint, and are relatively rare in children. More common is the Galeazzi equivalent lesion, where the radial fracture occurs with a distal ulnar physeal fracture (Fig. 19.41). Multiple subtypes have been classified (Letts and Rowhani 1993), most of which can be treated with closed manipulation and cast fixation. If the radial fracture is complete rather than greenstick, internal fixation will be required. 

Fig. 7.70 Maximum tensile stress S in ceramic layer versus effective time to radial fracture tR for as-polished Y-TZP and alumina plates bonded to polycarbonate substrates. Data represent individual tests at constant monotonic stressing rates (unfilled symbols) and in cyclic loading at 10 Hz (filled symbols). Solid lines are data fits in accordance with slow crack growth relations. Arrows indicate runouts [35]. With kind permission of Elsevier...

Catheters must withstand often substantial stresses, from the weight of urine when the collection bag is full, as well as from movement of the user, and these stresses induce fatigue. The catheter can break near the tip, in which case the end must be extracted surgically. Just this happened to a patient, Miss C, in 2007, and she experienced great discomfort and pain, not to mention distress without the device before a new catheter was implanted. The failed parts were returned, and she gave them to her pharmacist for examination, but they were discarded or lost, and so the cause of failure was never determined. However, the replacement catheter she was sent showed failure of almost exactly the same kind, and she sued the manufacturer as a result. The presence of a clean radial fracture (Fig. 9.33) without any applied stress implied a manufacturing defect in the material, vulcanized silicone rubber. 

Figure 1.5. Tangential stress at the surface of a ceramic for different indent sizes. These stresses cause radial fracture.

Example 5-2. Circular borehole with two symmetric radial fractures. 

The problem is simply stated can we transform this limit solution for a straight line, available analytically, into one describing the flow from a circular borehole with two symmetric radial fractures The answer is, Yes. To do this, let us first define a new function... 

Example 5-3. Circular borehole with two uneven, opposite, radial fractures or, a single radial fracture. 

Now we consider the same circular borehole but with two uneven, opposite radial fractures. Following Example 5-2, we again consider the function... 

The final schematic is given in Figure 5-3. in the additional limit 8 = 0, we recover single fracture only results the foregoing abscissa values now become = -s and + s, leading to centered fracture results. Also, the X-shift 8 can be chosen so that a single radial fracture appears in place of two. 

Figure 5-3. Circular hole with nonsymmetric radial fractures.

Example 5-4. Circular borehole with multiple radial fractures. 

Example 5-4. Circular borehole with multiple radial fractures, 89 Example 5-5. Straight shale segment at arbitrary angle, 91 Example 5-6. Infinite array of straight-line shales, 94 Example 5-7. Pattern wells under aquifer drive, 95 Three-dimensional flows, 96 Example 5-8. Point spherical flow, 97 Example 5-9. Finite line source with prescribed pressure, 97 Example 5-10. Finite line source with prescribed flow rate, 99 Example 5-11. Finite conductivity producing fracture having limited areal extent, 100... 

New approaches to old problems are emphasized. For example, how do mathematical aerodynamicists turned petroleum engineers view the physical world Stare up the back end of a rocket lifting off Is that a fuselage with stabilizer fins, or is it a circular wellbore with radial fractures Pry open the maintenance box of your typical jet engine Are those cascades of airfoil blades, or are they distributions of stochastic shales Can the solutions that describe brittle failure be repackaged to model arrays of fractures, say, the natural fracture systems that spur horizontal drilling Very often, the problems (inaccurately) crunched by our fastest computers can be solved (accurately) using closed-form analytical solutions found in other scientific disciplines. 

Indentation by spherical metal ball -25 Upper (radial fracture to no fracture) Puttick [111]... 

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