ST102 · Hinged Beam on Two Supports

Experimental apparatus for the direct measurement of shear force and bending moment in a simply-supported beam

A simply-supported beam cut at one-third of its span and rejoined by a low-friction two-degree-of-freedom hinge. Two calibrated force gauges across the hinge read the internal shear force and bending moment at that section directly — turning the method of sections from a sketch on the blackboard into a measurement the students can verify against their own equilibrium calculations.

Experiments

Determination of support reactions from the conditions of static equilibrium; verification against the force gauges on the two bearings
Application of the method of sections to compute the internal shear force $Q$ and bending moment $M$ at the cut
Construction of the full $Q(x)$ and $M(x)$ diagrams for:
- a single point load at an arbitrary position
- two or three simultaneous point loads
Experimental verification of the differential relations $\tfrac{dQ}{dx} = -q$ and $\tfrac{dM}{dx} = Q$ at the hinge location
Quantitative comparison between calculated and measured values of $Q$ and $M$ — illustrating the small magnitude of $Q$ relative to $M$ that motivates bending-dominated component sizing
Discussion of the sign conventions for internal forces and the interpretation of positive / negative regions of the $Q$ and $M$ diagrams

Beam & supports

Total length 1100 mm

Span between supports 800 mm

Hinge position 1/3 of the span, 2 DoF, low-friction

Supports 2 roller supports with horizontal-alignment adjusters

Load positioning 1000 mm tape, 1 mm graduation

Loading 1 to 3 simultaneous point loads, any position along the beam

Measurement

Shear force (Q) force gauge, ±50 N

Bending moment (M) force gauge (±100 N) × lever arm 100 mm → ±10 Nm

Zero adjustment adjuster nuts on both gauges for beam levelling

Load set

Weights 3 × 1 N hangers · 3 × 1 N holders · 12 × 1 N · 9 × 5 N

Maximum load per hook 20 N

Delivery

Experimental unit (frame, beam, supports, hinge, dial gauges)
Complete calibrated weight set
Stackable storage case with foam inlay
Instruction manual with worked experiments

40 kg