Realisation of 3D In-situ Assessment of Local Crack Driving Forces via Ultra-high Resolution Synchrotron Xray CT

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Impact safety of transport machines strongly depends on materials themselves. Recently, due to light-weightening of machines, since materials behaviors include inherent impact phenomena, it is strongly required for their evaluation to have mechanical consideration and expertise different from usual materials tests. Various properties data under high strain rate loading, which are available in the current literature, seem to be doubtful in its accuracy. Strength and structural analyses based on uncertain data give the least reliability. In the present study, mainly within the range of monotonic tensile test and fracture toughness test of materials, it has been investigated on the measuring procedures of load and strain. Especially, how to measure mechanical properties is shown for anyone using any testing machines for any materials over a wide temperature range. Also, how to measure accurately is shown as forms of easy standards for operators of testing machines without expertise.Concre … More tely speaking, as model materials for steels and non-ferrous metals, IF steels and 6000-series aluminum alloys were used. These two alloys have been extensively used for bodies and bumpers of automobiles in which the highest safety is required in our country as mechanical structures. Testing conditions and issues on accuracy have been clarified when these materials are tested. Using valid and accurate impact property data for the materials which cover wide ranges of temperature and rate between static and high speed conditions, constitutive equations under impact loading for plastic deformation of metallic materials, which have been matters of controversy for a long time, has been checked for a wide strain rate range. Strain-rate dependency of materials properties and strain rate history effects have been also re-arranged and investigated theoretically. In addition, not only providing materials test methods and test data which can contribute practically to impact safety of transport machines and reliability assurance, but also helping fundamental interpretation of materials deformation behaviors, this research area has been summed up academically within the 20^<th> century. Less