Forces in an Overdeterminate Truss
The picture shows SE 110.22 in a frame similar to SE 112.
* Comparison of forces in statically determinate and overdeterminate trusses1 * Bars with strain gauge full bridges to measure bar force1 * Computerised evaluation of experiments Technical Description Overdeterminate trusses are employed where overdimensioning is purposely required because safety must be maintained in the event of failure of an element, such as in aircraft construction. With additionally inserted bars a statically determinate truss becomes internally statically indeterminate. In this case the truss is termed statically overdeterminate. The SE 110.22 experimental set-up permits investigation and comparison of statically determinate and statically indeterminate trusses. Using the bars and node discs, a statically determinate, single plane truss is first constructed. On installation of a surplus bar the truss becomes overdeterminate. By way of a load application device, straight or inclined forces are applied to the truss, thereby simulating various load cases. The occurring tensile and compressive forces in the bars are recorded by means of strain gauges. Computerised evaluation is provided by measurement amplifier FL 151. The software is used to manage the measurement data and provide graphical representation of the bar forces. The software features a comprehensive help function. The various elements of the experiment are clearly laid-out and housed securely in a storage system. The complete experimental set-up is arranged in the frame SE 112.
The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments. Learning Objectives / Experiments - Measurement of the bar forces in a statically determinate and statically overdeterminate, single plane truss - Distribution of forces in the single plane truss dependent on the use of a surplus bar - Dependency of...