a. Plot data points of the SWT parameter, max a, versus N on log-log coordinates. Also plot the curve expected from the constants in Table 15.1, and comment on the success of the SWT parameter for this material. b. Using the modified Morrow approach, Eq. 15.26, plot the members of the family of strain- life curves that correspond to mean stresses of m = 0, 72, 143, and 290 MPa. Then plot the test data and comment on the agreement with the curves. Table 15.1 Cyclic Stress-Strain and Strain-Life Constants for Selected Engineering Metals. 1 Tensile Properties Cyclic - Curve Strain-Life Curve Material Source 00 of B %RA E H' n' % b ' (a) Steels SAE 1015 (8) (normalized) Man-Ten (hot rolled) 322 557 990 67 (46.7) (80.8) (144) RQC-100 (roller Q&T) 683 758 1186 (99.0) (110) (172) 64 SAE 1045 (6) (HR & norm.) 382 621 985 (55.4) (90.1) (143) 51 SAE 4142 (1) (As Q, 670 HB) 1619 2450 2580 6 (235) (355) (375) SAE 4142 (1) (Q&T, 560 HB) SAE 4142 (1) (Q & T, 450 HB) SAE 4142 (1) (Q&T, 380 HB) AISI 4340 (3) (Aircraft Qual.) AISI 4340 (1) (409 HB) Ausformed H-11 (1) (660 HB) 1688 2240 2650 27 (245) (325) (385) 1584 1757 1998 42 (230) (255) (290) 1378 1413 1826 48 (200) (205) (265) 1103 1172 1634 56 (160) (170) (237) 1371 1468 1557 38 (199) (213) (226) 2030 2580 3170 33 (295) (375) (460) (b) Other Metals 2024-T351 Al (1) 379 469 558 25 (55.0) (68.0) (81.0) 2024-T4 A13 (Prestrained) 303 476 631 (44.0) (69.0) (91.5) 35 7075-T6 Al (5) Ti-6Al-4V (soln. tr. & age) Inconel X (1) (Ni base, annl.) 228 415 726 68 (33.0) (60.2) (105) 469 578 744 33 (68.0) (84) (108) 1185 1233 1717 41 (172) (179) (249) 703 1213 1309 20 (102) (176) (190) 207,000 1349 0.282 (30,000) (196) 203,000 1096 0.187 (29,500) (159) 200,000 903 0.0905 (29,000) (131) 202,000 1258 0.208 (29,400) (182) 200,000 2810 0.040 (29,000) (407) 207,000 4140 0.126 (30,000) (600) 207,000 2080 0.093 (30,000) (302) 207,000 2210 0.133 (30,000) (321) 207,000 1655 0.131 (30,000) (240) 200,000 1910 0.123 (29,000) (277) 207,000 3475 0.059 (30,000) (504) 73,100 662 0.070 (10,600) (96.0) 73,100 738 0.080 (10,600) (107) 71,000 977 0.106 (10,300) (142) 117,000 1772 0.106 (17,000) (257) 214,000 1855 0.120 (31,000) (269) 1089 -0.115 0.912 -0.606 (158) 938 -0.0648 1.38 -0.704 (136) 948 -0.092 0.260 -0.445 (137) 2550 -0.0778 0.0032 -0.436 (370) 3410 -0.121 0.0732 -0.805 (494) 1937 -0.0762 0.706 -0.869 (281) 2140 -0.0944 0.637 -0.761 (311) 1758 -0.0977 2.12 -0.774 (255) 1879 -0.0859 0.640 -0.636 (273) 3810 -0.0928 0.0743 -0.7144 (553) 927 -0.113 0.409 -0.713 (134) 1294 -0.142 0.327 -0.645 (188) 1466 -0.143 0.262 -0.619 (213) 2030 -0.104 0.841 -0.688 (295) 2255 -0.117 1.16 -0.749 (327) 1020 -0.138 0.439 -0.513 (148) (15.26) Ea 1 E - m Om (2N)+(2N}) 0'f 15.21 Some strain-life data at nonzero mean stresses are given in Table P15.21 for prestrained 2024- T4 aluminum. Table P15.21 Ea a, MPa m, MPa Nf, cycles 0.00345 245 71.7 37 800 0.00232 165 71.7 244 600 0.00172 122 71.7 760 000 0.00410 291 142 11 000 0.00303 215 141 30 000 0.00254 181 144 58 500 0.00198 143 143 158 000 0.00148 105 142 437 100 0.00121 85.5 144 820 000 0.00250 178 292 27 700 0.00149 106 292 200 000 0.00109 76.5 287 747 000