Question

Q1-D In a fatigue test, a number of specimens should be prepared from the same batch of material. Starting at comparatively high values for the magnitude of the stress reversal, cach specimen is tested to failure at a successively lower level of stress reversal. The magnitude of the stress reversal and the number of cycles to failure are recorded graphically for cach specimen. Plot the expected trend of strength versus number of cycles for mild steel material. [30 Marks] Answer of O 1-D 104 10 5 10* 10 10* Numbers of cycle to failure I Strength, MPa

Answer 1

400 Hatigue Loimie Siress beioh Jatique Limit gives 'ainlbinite tiye' Mil Stul 300 20 0 00 106 Nunrber oh eycdos Moilrene N) Ithe above graph also cald as SN cuve whih is usually specimens tuvo urd d static tensile datermined loy sng 8 to (2 t starts Nith a trsngih oh maleial do not ai in Stress Ihe strass is owesed till specimens 10 JAre strel comes under the catagoay w rese stress auves 'very Romy ije and paligee/Endurance kemit AeRiow hekreshokd value Scanned with CSCansserasser value is called Strengte (mpa)