ASTM E1942-98e1

1.1 The purpose of this guide is to understand and minimize the errors associated with data acquisition in fatigue and fracture mechanics testing equipment. This guide is not intended to be used instead of certified traceable calibration or verification of data acquisition systems when such certification is required. It does not cover static load verification, for which the user is referred to the current revision of Practices E4, or static extensometer verification, for which the user is referred to the current revision of Practice E83. The use is also referred to Practice E467.

1.2 The output of the fatigue and fracture mechanics data acquisition systems described in this guide is essentially a stream of digital data. Such digital data may be considered to be divided into two types - Basic Data, which are a sequence of digital samples of an equivalent analog waveform representing the output of transducers connected to the specimen under test, and Derived data, which are digital values obtained from the Basic Data by application of appropriate computational algorithms. The purpose of this guide is to provide methods which give confidence that such Basic and Derived Data describe the properties of the material adequately. It does this by setting minimum or maximum targets for key system parameters, suggesting how to measure these parameters it their actual values are not known.