Instruction

The AE Mechanical Testing facility is used regularly for instruction in several courses. Laboratory testing is carried out by AE Machine Shop staff.

Freshmen in Engineering Mechanics take an introductory course, Mechanics in the Modern World, part of which is devoted to a team-oriented design project. In recent semesters, the challenge has been to design and build a wooden structure with 2x4s and wood screws that maximizes the load-toweight ratio for a prescribed loading condition.

TAM 195

Near the end of the semester, the teams compete by placing their structures, in turn, in the compression region of the Southwark- Emery testing machine. The failure loads are usually of the order of a few kips—very small compared with the loading capacity of the testing machine—but with a sensitive pressure transducer attached to the Tate- Emery load cell, failure loads can be determined to the nearest 0.1 kip (100 lb, about 500 N).

A conventionally designed truss carries a modest load before failure. An important lesson learned is that the strength of joints is critical to the design.

Juniors in civil engineering and in engineering mechanics complete a comprehensive lecture–laboratory course inBehavior of Materials. The split-cylinder, or indirect-tension, test is used in one of the laboratory sessions to determine the tensile strength of concrete by means of transverse compressive loading, which by equilibrium requires a nearly uniform tensile stress perpendicular to the axis of loading. The 890 kN (200 kip) Riehle testing machine is used for this test.

CEE 300 / TAM 324

The 4-point bend test is used to determine the flexural strength of concrete, using a modified ASTM jig in

the 530 kN (120 kip) Riehle testing machine.

Direct compression tests are carried out in the 13 MN (3000 kip) Southwark-Emery testing machine. An extensometer is used to monitor axial strain, so that stress–strain curves can be determined for both lowstrength and high-strength concrete samples.

TAM 456

The 13 MN (3000 kip) Southwark-Emery testing machine is often used in the University’s Experimental Stress Analysis course. An example is the strain-gaging of an A36 I-beam at multiple locations on both sides of the web, and loading the I-beam in nonsymmetric 3-point loading. Comparisons of the strain-gage data with theoretical predictions from elementary beam theory and contact theory reveal regions in which the elementary beam theory is applicable.