Question

3. Figure Q.3 shows the undercarriage of a drone aircraft, made of a hollow circular pipe with an external radius r and wall thickness t. During braking, a force F acts perpendicular to the plane of the bracket, and a vertical force P due to the aircraft weight is present simultaneously. Assuming plane stress, and given that a=0.1 m, b=0.2 m, r =0.01 m, t=0.00224 m, F =100 N and P =1000 N: a) Find all the stress components acting on point A in Figure Q.3. a) b) Draw the Mohr's circle for the stress state at A. c) Find the principal stresses at A. d) Find the maximum shear stress at A. e) What type of load is the main contributor to the stress state at A? side view Front view ШIL Figure Q.3

Answer 1

Principal stresses at A Juz = 96.12 = 95.88 192 MP 62=-.24 M Pa sheer stress at A MQximuum Tmax = Tman = 96.12 M Pa bending Main contribten d stress is loed P stress olue to

(1-), = 9988 m p CACW when wewed from top) %3D Shear stress at due force %3D Fx4 a(d'- di) %3D ( backaserd direction) = - 3.2 MPe Net longitud nal strers in y-dizection =(5)p + ), MPe G = 191. 76 on X- y blane Net Sheas strees = (), + (Tman)F 6.788 M Pa てこ て↑ here = 191.76 M Pe = 6.788 MRe a je 5)

Q= 100 mm b= 200 mm do-27 d. = 20 mm di= 20- 2x 2.24 lgad Stresses at A due to ot P:-) = 15-52 mm bre ১he১ : (0), = P = 1000 N - Px4 [ do' -di) F= l00 N Bending stvess :-> 10), = Pa x do/2 X364 %3D n( di -di) 199.76 MPe (tensile. Stresses at due to frichianal force E Twisting stress, FQ x do/z x 32 n [di- di]