Structures - Trusses

This kit allows students to apply loads in different places on the non-redundant truss and redundant truss to explore the tension and compression forces within each truss member.

There are 7 load cells on each of the 7 truss members which is connected directly to an LCD display for the output and to the USB interface for data acquisition. The LCD will display the output with positive or negative values so that students can understand which truss member is in tension or compression. Zero buttons next to the LCD display allows for the student to zero the load cell output and setup the experiment each time.

This kit consists of one redundant member which can be engaged or disengaged using the thumb screws.

• When the redundant member is disengaged from the other 6 truss members, students can learn to analyse the 6 truss members using Method of Joints and Method of Sections while using Bow’s notation. This experiment setup is for exploring the non-redundant truss.
• When the redundant member is engaged to the other 6 truss members, students can learn to analyse the 7 truss members using Method of Virtual Work, Method of Joints or Method of Sections. Students can also determine the redundancy using (m+r) <=> (2j) test. The redundant member has a twisting mechanism which allows its length to be adjusted easily. This experiment setup is for exploring the redundant truss.

Students can learn to calculate the theoretical member forces and compare these with the experimental member forces.

Two hanging positions allow for students to explore the idea of redundancy in frameworks and how load is transmitted through the system. A magnetic pulley allows for students to apply angled loads as well.

Construction is made in 2mm mild steel, providing a strong and stiff base to perform experiments on.

Learning Objectives

• Member Forces when:

           -         the position & angle of the applied load is different.

           -          the mass of load is increasing.

           -         the truss has non-redundant member.

           -         the truss has a redundant member.

• Bow’s Notation
• Method of Joints
• Method of Sections
• Method of Virtual Work
• Determine Redundancy using (m+r) <=> (2j) test
• Determine tension or compression for each member forces.
• Comparison of theoretical member forces vs experimental member forces.