FAIZURE ANAZYSIS CASE SZZLDIES II ppt

FAIZURE ANAZYSIS CASE SZZLDIESII Edited by D.R.H. Jones Pergamon [...]... the case) The torque required to cause shear fracture of the core is then given by r = 27c 23.5mm 0 (700+8.78x 10-3r')r2drNmm=2.06x 107Nmm (7) The torque required to cause shear fracture of the case can be found from the standard expression [41 r =2zk,(r:3 - r:) ' (8) where Y, (= 25 mm) is the outer radius of the case, and rz (= 23.5 mm) is the inner radius of the case Since k , x 1760MPa for the case, ... testing Figure 8 is a macrograph of the polished cross-section after etching in 2% nital The case- 15 Fig 8 Polished cross-section through the shaft, showing the case- hardened layer Table 2 Hardness measurements on shaft cross-section as a function of radial distance from the centre r (mm) HV 0 10 17.5 22.5 Case 350 360 375 400 880 (MW ~ T S 1120 1152 1200 1280 2816 k, (MPa) 700 720 750 800 1760 measured... ball bearing I Salam, A Tauqir, A U1 Haq and A.Q Khan 415 Failure analysis of a condensate pump shaft A.M Lancha, M Serrano and D Gdmez Briceiio 425 Author Index 443 Overload failures Failure Analysis Case Studies II D.R.H Jones (Editor) 0 2001 Elsevier Science Ltd All rights reserved 3 BURSTING OF A SILO R KIESELBACH Failure Analysis of M t l ,Swiss Federal Laboratories... EMPA Failure Analysis Case Studies N D.R.H Jones (Editor) 0 2001 Elsevier Science Ltd All rights reserved 11 SHEAR FAILURE OF A ROAD-VEHICLE STEERING SHAFT J H CLELAND Cambcor Ltd, 30 Windsor Road, Cambridge CB4 3JW, U.K and D R H JONES* Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 lPZ, U.K (Received 20 September 1996) 1 BACKGROUND This case study describes the... manufactured from a nickel-chromium-molybdenum steel, and was subsequently case hardened The specified composition is given in Table 1 The specified properties of the core in the quenched condition were as follows: yield stress, 736 MPa minimum; tensile strength, 10791324MPa; elongation, 8% minimum; impact energy, 59 J cm-’ minimum The case was required to have a Rockwell C-scale hardness of 59-63, equivalent... due to suffocation or gas poisoning of the farmers entering a silo Some are also caused by the explosion of methane, which is produced by fermentation of the forage Cases of bursting or explosion are, nevertheless, rather rare In the present case, three identical silos had been built on a farm, each with a diameter of 6 m (20 ft) and a height of nearly 25 m (80 ft) The hull of the vessels was made of... shaft had been inadequately tempered Table 2 shows that the hardness of the case (HV 880) is significantly higher than that specified (HV 68G780) However, there was no indication that this contributed to the failure As shown in Figs 3 and 4, the splines were able to withstand a considerable shear strain even though they were case- hardened The maximum engineering shear strain suffered by the splines... Specimens for mechanical tests Table 2 Results of tensile tests on sheet material from silo Specimen Orientation BR CR BP CP Ito joint I to joint 11 to joint 1) to joint Yield strength (N ~II- ~) 288 261 300 278 Tensile strength (N ~II- ~) 341 316 345 313 Reduction of area (”/) Elongation (5 diameters) 18 44.5 I1 IS 47.5 43 46.3 70 (”/I Uniform elongation (”/) 25 24 24 29 7 30 - 20- f fi.2 I I I I I 5 10 15 20... failure torque is 0.98 x lo7N mm The total torque is therefore (2.06+0.98)= 3.04 x 107Nmm It is interesting to notice that, even though the case is only 1.5mm thick, it is responsible for nearly one-third of the total torsional strength This is partly because the case is more than twice as strong as the core, and partly because the torsional strength depends on the cube of the radius It should be stressed... Corporation, Swindcn, 1980 3 Parrish, G and Harper, G S., Producfion Gus Carburising Pergamon Press, Oxford, 1985 4 Jones, D R H., Engineering Materials 3 Pergamon Press, Oxford, 1986 Failure Analysis Case Studies II D.R.H Jones (Editor) 0 2001 Elsevier Science Ltd All rights reserved 19 BREAKUP OF THE FIREWALL BETWEEN THE B AND C MODULES OF THE PIPER ALPHA PLATFORM-I ANALYSIS BY HAND CALCULATION A C PALMER . FAIZURE ANAZYSIS CASE SZZLDIESII Edited by D.R.H. Jones Pergamon