Design of Machi...

Stress concentration may be caused by

A machine component is subjected to stress of 80 MPa for 60% of time and 180 MPa for rest of time. The fatigue life are 10⁶ cycles and 4 × 10⁴ cycles for 80 and 180 MPa respectively. The fatigue life of component is

The thickness of the continuous weld used for connecting a horizontal square bar of 150 mm size and of cantilevered length 500 mm to a vertical plate, with the bar carrying a 25 kN vertical load at its outer tip, given that the permissible direct shear stress of the weld is 20 N/mm², is

A shaft of 50 mm diameter transmits a torque of 800 N-m. The width of the rectangular key used is 10 mm. The allowable shear stress of the material of the key being 40 MPa, the required length of the key would be

Life of a ball bearing is 700 million revolutions for a load of 5 kN. The life of bearing for 10 kN is (in million rev.) _______

The tearing efficiency of a rivet joint is 70%. For a pitch of 15 mm, the rivet diameter is ______ mm

In a cotter joint, the width of the cotter at the center is 5 cm, while its thickness is 12 cm. The load acting on the cotter is 60 kN. The shear stress developed in the cotter is

Square key of side "d/4" each and length l is used to transmit torque "T" from the shaft of diameter "d" to the hub of a pulley. Assuming the length of the key to be equal to the thickness of the pulley, the average shear stress developed in the key is given by

A concentric spring to be used as a valve spring in a heavy duty diesel engine has a spring index of 6. The Wahl’s correction factor for the spring will be ________

A journal bearing sustains a radial load of 3672 N. The diameter of the bearing is 50 mm and the length is 0.1 m. The diameter clearance is 0.1 mm and the shaft rotates at 500 r.p.m. if the absolute viscosity of the oil is 0.06 kg/m-s, the value of Sommerfeld number is

Two plates having identical thickness of 5 mm are to be joined by a double riveted lap joint. The allowable crushing and shear stress for the rivets is 100 MPa and 70 MPa. The required rivet diameter will be ____________ mm

A 60 mm long and 6 mm thick fillet weld carries a steady load of 15 kNalong the weld. The shear strength of the weld material is equal to 200MPa. The factor of safety is

A plate clutch is used to transmit power of 75 kW at 1000 rpm. µ = 0.25 and maximum pressure intensity is 0.825 MPa. Ratio of outer and inner diameter is 4/3. The inner diameter of friction surface with single pair of mating friction surfaces is (mm)

In a gib and cotter joint, the gib and cotter are subjected to

In a cotter joint, the width of the cotter at the centre is 50 mm and its thickness is 12 mm. The load acting on the cotter is 60 kN. What is the shearing stress developed in the cotter?

When a circular rod of diameter d, welded of a rigid plate, by a circular fillet weld of size t, is subjected to a twisting moment T, then shear stress induced in the weld is given by ____

A steel shaft is subjected to an axial load varying from 30 kN in compression to 130 kN in tension. The endurance limit, yield strength and ultimate strength of shaft material is 180 MPa, 400 MPa and 650 MPa respectively. For a factor of safety of 1.5, the diameter of shaft according to Goodman’s criterion is

A machine component is subjected to fluctuating stress that varies from 40 to 100 N/mm². The correct endurance limit is 270 N/mm². The ultimate tensile strength and yield strength of material are 600 and 450 N/mm² respectively. Determine the ratio of factor of safety using soderberg line to factor of safety against static failure   ________

A pinion made of steel has a module of 3 mm, pressure angle 20  and has 20 teeth. It runs at 900 rpm and transmits 15 kW to a 60-tooth gear. The face width of the gear tooth is 40 mm and the velocity and form factors are 0.55 and 0.32 respectively. The bending strength of the pinion tooth as per the Lewis beam strength equation is:

A spur gear system having a pinion pitch circle diameter is 200 mm, face width of tooth is 60 mm with velocity ratio 1:2 and material combination factor for wear is 1.5 MPa, then the tooth wear load carrying capacity is, _____ kN

A pulley is connected to a power transmission shaft of diameter d by means of a rectangular sunk key of width wand length ‘l’. The width of the key is taken as d/4. For full power transmission, the shearing strength of the key is equal to the torsional shearing strength of the shaft. The ratio of the length of the key to the diameter of the shaft (l/d) is

A ball bearing is subjected to a radial force of 2500 N and an axial force of 1000 N. The dynamic load capacity of the bearing is 7350 N. The X and Y factors for the bearing are 0.56 and 1.6 respectively. The shaft rotates at 720 rpm. The life of the bearing in hours, is ___________

The following two figures show welded joints (x x x x x indicates welds), for the same load and same dimensions of plate and weld.

The joint shown in

Two steel shafts, one solid of diameter D and the other hollow of outside diameter D and inside diameter D/2, are twisted to the same angle of twist per unit length. The ratio of maximum shear stresses in solid shaft to hollow shaft is_____

A differential band brake is shown. The width and thickness of 150 mm are 5 mm with maximum tensile stress in the band is 75 MPa. The coefficient of friction between the friction lining and brake drum is 0.5. The torque capacity of the brake is ______ kN-m