Measurement and analysis of fatigue crack deformation on the macro- and micro-scale

The paper describes an experiment which performs in-situ loading of a small compact tensionspecimen in a scanning electron microscope. Images are collected throughout a number of successive loadincgcycles. These are then analysed using digital image correlation (DIC) in order to produce crack flankdisplacements as a function of load. This data is then compared with a simple elastic approach, and it is concludedthat elastic-plastic analysis is required in order to accurately capture the displacements close to the crack tip. Asimple approach due to Pommier and Hamam is therefore employed. This gives a better representation of thedata, but predicts a variation of crack tip displacement, ?, which is difficult to explain from a physical perspective.The need for a more sophisticated analysis of the data is therefore highlighted

Measurement and analysis of fatigue crack deformation at the micro-scale

This paper introduces the use of digital image correlation for the measurement of surface displacements in the neighbourhood of a crack tip, both at the macro- and micro- scale. Various methods of interpreting the measured data and producing a crack driving force are then discussed, including the use of the full CJP model. A reduced set of parameters are then proposed, corresponding to the three principal interaction forces between the plastic enclave and the surrounding elastic material. Our own results, and those of Vasco Olmo, previously reported in the literature are then reanalysed using this new framework, and excellent agreement between two independent experiments is obtained. Implications for the analysis of further data sets are then discussed

Measurement and analysis of fatigue crack deformation on the macro- and micro-scale

The paper describes an experiment which performs in-situ loading of a small compact tension specimen in a scanning electron microscope. Images are collected throughout a number of successive loadincg cycles. These are then analysed using digital image correlation (DIC) in order to produce crack flank displacements as a function of load. This data is then compared with a simple elastic approach, and it is concluded that elastic-plastic analysis is required in order to accurately capture the displacements close to the crack tip. A simple approach due to Pommier and Hamam is therefore employed. This gives a better representation of the data, but predicts a variation of crack tip displacement, , which is difficult to explain from a physical perspective. The need for a more sophisticated analysis of the data is therefore highlighted

Novel applications of ESEM and EDX for the study of molecularly thin amide monolayers on polymer films

This work reports novel Environmental Scanning Electron Microscopy (ESEM)/Energy Dispersive X-ray (EDX) measurements on the equilibrium composition and kinetics of alkyl amide adsorption at the polymer-air interface. This experimental approach provides certain advantages over other existing techniques for the study of the physisorbed molecules and offers potential for further development