Flexible Sequential Fatigue Tester

The Flexible "Sequential" Fatigue Tester is a pneumatically driven cyclical load application machine that is P.C. controlled with fully programmable load profiles.  It includes a very flexible mechanical arrangement with multiple loading cylinders.  The largest cylinder can apply loads of up to 750 pounds (340 Kg) in either direction using 100 PSI shop air.

Generally, the design of these machines can be best described as an erector set.  The worktables are mounted on casters with brakes, and include integral forklift tubes.  The work surfaces are ground steel with rectangular arrays of holes tapped through them.  All of the vertical frame members can be bolted to the top surfaces, anywhere along the perimeters.  The horizontal cross members can then be manually slid up and down and clamped in position.  The loading heads, which include the pneumatic cylinders, can be slid sideways and clamped in position.  The cylinders on the load heads can also be rotated and clamped in position.

Each cylinder is controlled with a single servo-pneumatic directional valve that is connected to the main control console.  The load application of each cylinder is continuously monitored in a closed-loop operating scenario, from the load cell back to the servo controller, to maintain the greatest accuracy and speed of operation.  Each cylinder also includes an internal displacement transducer for data acquisition of position while under load.

The P.C. based control system is mounted in a floor standing console that is separate from the test stands.  The custom software is written in Visual Basic and is simple to operate for anyone familiar with Windows.  Almost any type of loading wave profile can be generated for each cylinder and then arranged into a test sequence.  This test sequence then consists of differing wave profiles, each with their own cycle counts.  This sequence can then be repeated as a loop counter.  The combination of these two features gives this fatigue control system incredible versatility.

Data acquisition of actual load verses theoretical load, and the resulting displacement, for each cylinder, is plotted on the monitor.  There is a wide selection of user and display options available using standard pull-down type menus.  The final graphical result can then be printed on the plain paper color ink jet printer, which is also housed within the console.  Final test data can also be saved or downloaded onto any other suitable P.C. type format.

This test system operates on 115 V.A.C. and shop air (other voltages available).  Set-up and operation requires minimal training and most technicians can master it within an hour or so.

Other variations of this tester are possible upon request.  Please call for details.

choose image to enlarge