[ensc 13] Probset 1 - Stresses (2nd_sem_ay2016-2017) 4p3n68

DEPARTMENT OF ENGINEERING SCIENCE College of Engineering and Agro-Industrial Technology University of the Philippines Los Baños

ENSC 13 – Strength of Materials 2ND Semester AY 2016-2017 PROBLEM SET 1 (STRESSES) 1.

The forged steel clamp exerts a force of N on the wooden block. Determine the resultant internal loadings acting on section a–a ing through point A.

2.

The shaft is subjected to the axial force of 40 kN. Determine the normal stress in the shaft, the average shear stress and average bearing stress acting on the collar C.

3.

During the tension test, the wooden specimen is subjected to an average normal stress of 2 ksi. Determine the axial force P applied to the specimen. Also, find the average shear stress developed along section a–a of the specimen.

4.

Find the maximum allowable value of P for the column. The cross-sectional areas and working stresses (σw) are shown in the figure.

5.

The pulley is held fixed to the 20-mm-diameter shaft using a key that fits within a groove cut into the pulley and shaft. If the suspended load has a mass of 50 kg, determine the average shear stress in the key along section a–a. The key is 5 mm by 5 mm square and 12 mm.

Problem 1

Problem 3

Problem 2

Problem 4

Problem 5

CCV/CLG/GMAT/ILEG

DEPARTMENT OF ENGINEERING SCIENCE College of Engineering and Agro-Industrial Technology University of the Philippines Los Baños

6.

The steel end-cap is fitted into grooves cut in the timber post. The working stresses for the post are 1.8 MPa in shear parallel to the grain and 5.5 MPa in bearing perpendicular to the grain. Determine the smallest safe dimensions a and b.

7.

The cross-sectional of each member of the truss is 1.8 in2. Calculate the stresses in mebers CE, DE, and DF. Indicate tension or compression.

8.

In the following lap t, six identical rivets are used to connect two . The allowable shearing stress on the rivets is 60 MPa; bearing stress between the rivet and the plate is 150 MPa; and the normal stress on the plate is 90 MPa. The plates connected are 300 mm wide and 16 mm thick. Also, the holes on the plates are 2.5 mm wider than the diameter of the rivets. Calculate the following: a. b. c. d.

9.

If maximum shearing stress in the rivets is considered, the allowable diameter of the rivets is? If maximum bearing stress is considered, the allowable diameter of rivets is nearest to? If normal stress on the plate is considered, the allowable diameter of the rivets is nearest to? What is the safest rivet diameter to use?

A triple-riveted lap t unites two 12-mmmm plates. The rivets are 25 mm in diameter and are spaced 150 mm in the outer rows and 75 mm in the inner row. When the tensile stress is 100 MPa in the gross section of the plate, determine; (a) the average intensity of the shearng stress in the rivets; (b) the average bearing stress on the plates; (c) the highest average tensile stress, and state where it occurs.

CCV/CLG/GMAT/ILEG

DEPARTMENT OF ENGINEERING SCIENCE College of Engineering and Agro-Industrial Technology University of the Philippines Los Baños

10. The smooth cylinder C has a radius of 0.3 m and a mass of 250 Kg. Neglecting the mass of bars, determine the normal and shear stress at section a-a. All bars have a square cross-sectional area of 2500 mm2. Also, determine the shearing stress at the 25 mm diameter pin C and bearing stress between pin C and bar BC. The uniform load W is equal to 10 KN/m. 11. The two-tine grapple s a log as shown. Determine the maximum mass of the log that the machine can carry if the maximum shear stress at pins B and D is 414 MPa and that the maximum normal stress at links AB and CD is 390 MPa. The diameter of the pins is 25 mm and the cross section of the links is 1200 mm2. The pins are subjected to double shear. Take a factor of safety equal to 3.

Problem 10

Problem 11

12. The frame s a load W. Member BD is 25 mm x 8 mm while all the pins are 15 mm in diameter. Using τ ult= 260 MPa in the pins and σult = 430 MPa in bar BD, determine the maximum load W if an overall factor safety of 2.5 is used.

CCV/CLG/GMAT/ILEG

DEPARTMENT OF ENGINEERING SCIENCE College of Engineering and Agro-Industrial Technology University of the Philippines Los Baños

13. A boiler is constructed of 0.4-in steel plates that are fastened together at their ends using a 0.4- in cover plate and rivets having a diameter of 0.3 in spaced 2 inches apart as shown. If the steam pressure in the boiler is 75 ksi, determine (a) the circumferential stress in the boiler’s plate apart from the seam, (b) the circumferential stress in the cover plate along the line a-a, and (c) the shear stress in the rivets.

14. A thin walled, T-shaped gas pipe is fabricated from plates having a tensile strength of 600 MPa as shown. Top and bottom plates are 20 mm thick, while plates on left and right sides are 10 mm thick. (a) Determine the allowable stress in the pipe in MPa. (b) What is the safe pressure (in KPa) inside the pipe considering longitudinal stress and (c) tangential stress? Use factor of safety equal to 2.0. 15. A pressurized cylinder has a sealed cover plate fastened with steel bolts. a) Determine the maximum pressure that can be applied if the allowable stress in the tank is limited to 7000 psi. The inside diameter D of the cylinder is 10in and the thickness of the cylinder is 0.5 in. b) Applying the maximum pressure, if 20 bolts will be used to fasten the cover plate to the tank, determine the diameter of bolt required such that the allowable stress in each bolt is limited to 10000 psi.

Problem 14

Problem 15

CCV/CLG/GMAT/ILEG