Overview

Abstract

The continuing advancement of computer and software technology has allowed for the automation of materials testing systems and processes to become commonplace. Automation, which was at first a very expensive and complicated accessory to a materials testing system, is now a inexpensive and often necessary subsystem. Many test techniques now require the speed, consistency, and computational capability inherent in these systems. Hardware cost~ have continued to spiral downward in conjunction with incredible increases in computational bandwidth, display technology performance, and mass storage capacity and speed. Software technology, the real key to forward progress, has improved significantly, allowing for shorter application development time with higher application performance. This is especially true in the area of real-time systems software which is critical for testing system control and data acquisition. This symposium is the third in a series of symposia concerned with the advancement of the state of the art in automated fatigue and fracture testing. The first was the Use of Computers in the Fatigue Laboratory held in New Orleans, Louisiana in November of 1975. The proceedings were published in STP 613. The second symposium on this topic was entitled Automated Test Methods for Fracture and Fatigue Crack Growth held in Pittsburgh, Pennsylvania during the Fall E9/E24 meeting in November of 1983. The proceedings of this symposium were published in STP 877. This current symposium was organized in order to conduct a state of the art review of the technology. The symposium was driven by the work of the task group E9.04.01 on Automated Testing which is a task group of the E9 committee on Fatigue and its' subcommittee on Apparatus and Test Methods. The intent of this task group is to conduct such a technology review on a three to four year time interval thus keeping pace with the rapid advances in computing and software engineering technology as they apply to fatigue and fracture testing. There are a number of areas where automation technology enhances fatigue and fracture testing. The emphasis of this symposium was placed upon the issues of test system implementation, test techniques, applications of networking and information management within a testing laboratory, control and data acquisition techniques, and applications or implementations where the computer provided enhanced analysis or simulation capability. These areas of interest were selected to focus on tasks in the fatigue and fracture testing process that reside at different levels within this process. Automated systems implementation and test techniques are closest to the actual tasks of acquiring materials property data. In this arena, concerns are primarily on compute bandwidth and real-time software efficiency. Fatigue and fracture tests, being dynamic tests, require higher data acquisition and compute bandwidth than many common real-time systems possess. The task of determining the crack length in a fatigue-crack growth test via the compliance technique for example requires data acquisition speed, simultaneity, and compute speed for online crack length calculations from resultant compliance data. Often the testing task requires parallelism in the system implementation to allow for control, data acquisition, and online conditional processing to be performed in the course of the test. This requires multitasking executive software or highly efficient single tasking environments that allow for prioritized interrupt driven system services or polling implementations with sufficient speed to handle all of the tasks at hand. A number of systems implementation oriented papers were presented in the first session of the symposium. The range of solutions