… of a 3D-body#
By applying equilibrium to the free-body diagram of a body you can find unknown forces and moments which prevent motion (translation and rotation). The concept of equilibrium of a body is treated in chapter 3.1.1 of the book Engineering Mechanics Volume 1 (Hartsuijker and Welleman, 2006). At maximum six unknown forces can be solved in a threedimensional problem. The steps involved are:
Draw a free body diagram of the body
Split the forces in convenient directions by applying resolution of forces
Solve the forces and moments using \(\sum F = 0\) in three nonparallel convenient directions and \({\left. {\sum T } \right|_{xy}} = 0\) for any arbitrary line \(xy\) as treated in chapter 3.3.2 of the book Engineering Mechanics Volume 1 (Hartsuijker and Welleman, 2006). The full procedure is shown in chapter 3.4.
Exercises#
If you’re a TU Delft student, you can practise with the following
exercises on threedimensional problems.