Fatigue testing eccentric machine

Figure 1.10 Diagram of an eccentric machine for tensile and compressive oscillation fatigue tests.

Servohydraulic, electrohydraulic, or pulsator fatigue-testing machines do not use an eccentric wheel to apply cychc stress and strain. These machines use a computer-controlled hydraulic drive or... 

At this point, a brief description of the test machine and necessary modifications seems in order. The machine is a Tatnall-Krause (5000-lb capacity) direct-stress fatigue machine with an eccentrically loaded lever arm. A hydraulic load-maintaining system is incorporated in the machine and is installed above the supporting columns. This system is electronically controlled. By using this system, a constant load pattern is maintained on the sample even though its length may increase during the test. 

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