Mechanical Engineering Design Notes

Design Contents

Preliminary Matters
Design Methodology
..brain storming
..evaluation matrix
Statistical Considerations
..variability in materials
..variability in dimensions
..variability in loading
.. preferred sizes
Design Factor
Introduction to Failure
Failure Theories
Stress Concentration
..and notch sensitivity
Failure Under Combined Loading
..combined bending and torsion
Failure Under Cyclic Loading
..fracture mechanics
Instability - Buckling
Concentrically Loaded Strut
..slender columns
..Euler formula
..effective length
..short and intermediate columns
Eccentrically Loaded Strut
.. theory
Shock Loading

Range of Materials
..performance indices
..ferrous metals
..alloying additions
..alloy and stainless steels
..tool steels
..aluminium alloys
..titanium alloys
..magnesium alloys

..bolts and bolted joints
..pre-load in bolts
..pre-load in bolts - example
..welds and welded joints

..forces acting
..curvature effect
..equations used for design
..materials and manufacture
..effective mass
..Java spring calculation applet with plot


..gear nomenclature
..gear box features
..friction belt drive
..hydraulics and pneumatics

Mechanisms and
4 stroke ICE thermodynamics

..engine mechanism and thermodynamics - applet
..engine mechanism - slider crank - velocity, acceleration diags. and torque, hand calculations

Bearings and Lubrication
..plain bearings
..viscous flow
..Petroff's law
..hydrodynamic bearing design


Interactive Bolt Calculation and Plot - Java Applet

Enter the required load. Click on the 'Plot' button, this puts a blue line accross the graph at the required load. To test if a particular bolt size and grade are suitable, enter values in the boxes and click on the 'Calculate' button. For common bolt sizes the coarse and fine pitch values are shown in the text box below the 'Plot' button. Valid inputs for the bolt grade are: 8.8 and 12.9.

The calculated load for any specific bolt input is the 'proof load'. Where cyclic loads are present, allowance should be made for the stress concentration effects caused by the thread form and for other fatigue life reducing factors. Although the plot only goes up to bolt diameters of 30 mm, values for larger bolt sizes can be put in, but the line may not be plotted on the chart.

Return to Notes on Bolted Joints

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