High school Yr 12 aeronautical Engineering Module - mechanics

PLease help- i seem to get the incorrect answer but didn't know where i have gone wrong? Problem: If each wing is to be 4.8m long and the lift force acts at 45% of the distance from the wing root, what will be the bending moment if the lift force is 9KN? What will be the bending stress if (Ixx = 1.8*10 power6 metres to the 10 power4, y = 20mm)

Stress and stain calculations

A mild steel shaft (modulus of elasticity = 210 GN/m2) has a stepped circular cross-section. Part A has a diameter of 75 mm and a length of 425 mm. Part B has a diameter of 60 mm and has a length of 375 mm. The shaft carries an axial tensile load of 65.0 kN. Determine: (a) The stress in Part A (b) The stress in Part B (c) The strain in Part A (d) The strain in Part B (e) The total extension of the shaft. (see attached file for diagram)

Shear stress calculation

The butt riveted joint shown below consists of two cover plates and three 8 mm diameter rivets in each main plate. (a) During testing, a tensile load is applied to the main plates. The load is increased until the joint fails at a load of 57.3 kN. Determine the ultimate shear stress of the rivet material. (see attachment for diagram)

Shear stress calculations

Aluminium alloy blanks are produced from sheet metal by a punching machine that generates a punching force of 30 kN. For sheet metal with a thickness of 3 mm the maximum diameter of the blanks is 13.0 mm. Determine. (a) The ultimate shear stress of the aluminium alloy. (b) The stress on the punch face. Please show workings and calculations.

Working speed in rpm

A transmission shaft is fitted with a coupling that is secured by eight 20 mm diameter bolts pitched on a circle with a diameter of 225 mm. The bolt material has an ultimate shear stress of 280 MN/m2 and a factor of safety of 4.0 is to be used. If the power being transmitted is 1.8 MW, determine the working speed of the shaft in revolutions per minute. Please show workings and solution.