Unsymmetrical Bending and Shear Centre (Next Generation Structures)
One of a range of experiment modules that fit to the Structures platform (STS1, available separately), the product helps students understand symmetrical and non-symmetrical bending of three diff erent beam shapes, including an equal ‘L’, a ‘U’ and rectangular. It also finds the shear centre of the channel (‘U’) beam.
For the symmetrical and non-symmetrical tests, a chuck clamps a beam while allowing rotation on its axis and allowing loads to be applied at various angles. Load applied at the free end produce resulting deflections, measured by a pair of precision indicators. Students plot their results on a Mohr’s circle which allows them to find the experimental Principal Second Moments of Area and position of the principal axes. These may be compared to those for the arbitrary section axes and the values calculated by textbook beam equations. This helps to confi rm the reliability of the textbook equations and the accuracy of the experiment results.
For shear centre tests, a chuck clamps the ‘U’ section beam. A plate clamped to the free end allows various off set loads to twist the beam. Students apply loads at various off sets and use the indicators to determine when the twist is zero, thus corresponding to the shear centre position.
This product includes a Vernier caliper for accurate measurements of the beam cross-sections.
The deflection indicators have their own displays, but they can connect to the USB interface nub of the Structures platform for computer display and data acquisition.
• Show that shear centre can be outside beam section boundaries
• Shear centre of an unsymmetrical section
• Horizontal and vertical defl ection in symmetrical and unsymmetrical sections at different loads and load angles
• Using Mohr’s circle to fi nd principal axes and Second Moments of Area