Point loads, probes and query points

In this step, we'll put two point actions on the same beam: a 50 kN point load 2 m from the left support, and a 30 kN m moment applied 4 m along the beam. The shear force diagram steps at the location of the force and the bending moment diagram steps at the moment. To identify the values between these points, we can use the probe - a readout that follows your mouse pointer along a member. In this step, we'll also meet query positions, which force the solver to return results at specific points you care about.

The model for this step: The 6 m beam under a 50 kN point load and a 30 kN m applied moment — The 6 m beam under a 50 kN point load and a 30 kN m applied moment. Orbit, read the results and hover the members; nothing you do here changes the model.

1.0 The idea

A point load is a force applied at one position along a member: the shear diagram drops by the load as you pass it, and the moment diagram has a kink there. An applied moment is a couple at one place: the moment diagram steps by the applied moment as you pass it, and the shear is the same on both sides. These are some of the most fundamental concepts for an engineer to understand - make sure to review this EngineeringSkills tutorial if you need a refresher.

Both applied actions belong to a member, at a position measured from its start node - and both can be read with the probe, which reports $N$ , $V$ , and at the point under your pointer.

Position	Point load: $V$ , $M$	Applied moment: $V$ , $M$	Both: $M$
1 m	33.33 kN, 33.33 kN·m	5.00 kN, 5.00 kN·m	38.33 kN·m
2 m, just before and after	33.33 kN then -16.67 kN, 66.67 kN·m	5.00 kN, 10.00 kN·m	76.67 kN·m
3 m	-16.67 kN, 50.00 kN·m	5.00 kN, 15.00 kN·m	65.00 kN·m
5 m	-16.67 kN, 16.67 kN·m	5.00 kN, -5.00 kN·m	11.67 kN·m

Point loads, probes and query points

1.0 The idea

2.0 The model

3.0 What you'll see

4.0 What the probe reads, and how

5.0 What to take from this step