STR20 - Experiment

BENDING MOMENTS IN A PORTAL FRAME

Allows students to investigate the sway, strains, stresses and therefore bending moments of a horizontally and vertically loaded rectangular portal.

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The experiment hardware fits onto the Structures Test Frame (STR1, available separately). Students use masses on weight hangers to apply various loads to a portal frame. A backplate holding the portal fits to the Test Frame. The portal has three members - a horizontal beam and two vertical members or ‘legs’ joined at two upper corners. All members are of the same material and have the same flexural rigidity (IE value). The backplate holds the bottom of the portal legs to form rigid fixings. The portal has sixteen strain gauges - eight along its horizontal member and four along each vertical member. The gauges connect to the Structures Digital Strain Display (supplied) to display their measured strain. 

As students apply loads, they use the measured strain to find the bending moment at the gauge positions and plot them on a diagram. They can then check the diagram against one created from theory. 

The hardware includes a digital indicator to measure horizontal deflection (sway) in the portal. It also includes a pulley bracket so students can apply horizontal loads and compare sway direction with that predicted from theory. The hardware also includes two removable moment arms. Students may fit one or both moment arms to the frame to simulate internal or external floor supports on the sides of a portal structure. Students can find the bending moments caused by these supports and compare with theory. 

The lecturer guide provides details of the equipment including sample experiment results. The student guide describes how to use the equipment and gives experiment procedures. 

For extra ‘virtual’ experiments, TecQuipment can supply the optional TecQuipment Structures Software (STRS), for use on a suitable computer. The virtual experiments simulate the tests you can perform with the hardware. They also extend the choice of tests beyond that available using only the hardware, for example: higher loads, uniform loads or different test specimens. This extends the student’s learning experience. 

For automatic data acquisition of your experiment results, TecQuipment can supply the optional Automatic Data Acquisition Unit (STR2000). Supplied as standard with the STR2000 is TecQuipment’s Structures Software that displays and logs your experiment results and gives the extra virtual experiments.

  • Strain gauge linearity
  • Using strain measurement to find the bending moment
  • Bending moments and sway for vertical and horizontal loads
  • Bending moments for internal and external moments on vertical members
  • Comparison of ideal and non-ideal structures
STR1 - Base Unit

A sturdy lightweight aluminium bench-mounting frame to provide rigid support for the interchangeable experimental modules in TecQuipment's Structures Range (STR2 -STR20).

STR2000 - Ancillary

A computer interface module with ADA software that allows the hardware experiments in TecQuipment's Structures Range to be interfaced to a PC.

STR18 - Experiment

An experimental apparatus to allow students to investigate the reactions and deflections of a loaded rectangular portal.