Papers by Keyword: Inelastic Deformation

Abstract: This paper investigates the impact of strain sensitivity on the linear model mock-up bearing (LMMB) using digital image correlation (DIC) technique. This work addresses the lack of norms, standards, reference of elastic/plastic deformation of bearings elements. Towards that, experimental set-up was designed and fabricated with a set of LMMB (AISI4140) with commercially purchased steel balls (AISI52100) to study the raceway relative approach and localized strain rate on steel ball, wherein raceway relative approach is measured using LVDT & screw gauge and results are compared with DIC results. These data are very much useful in design and development of large diameter slewing bearing for fast breeder reactor and also these results can be used to optimize the number of ball, load, and tolerance on bearing.

Abstract: Tension-torsion experiments at 680°C and 850°C on thin-wall tube specimens of DD3 nickel-based single crystal superalloys were successfully completed. It shows that specimens have stress relaxation obviously and inelastic deformation accumulation phenomenon with different crystal orientation under asymmetric cyclic loadings. Based on the microstructure characteristics of nickel-based single crystal superalloys, a two-phase multi-cell microscopic mechanical model was established by finite element method to simulate the test with displacement. Numerical simulation studies showed that the matrix phase appeared plastic deformation accumulation at first and resulted in low cycle fatigue damage, but stress distortion occurred on the boundary with a single cell model under tension-torsion displacement loading, which is not consistent with experimental results. While using multi-cell model can avoid this phenomenon, it could be better to simulate stress relaxation behavior under asymmetric cyclic loading at elevated temperature and to study on stress weaken damage for single crystal superalloys.

Abstract: It is the purpose of this study to present design equations which can be used to predict the damage of ductile plating when subjected to mass impact, dynamic pressure or impulsive loadings. The external loadings are sufficiently severe to produce inelastic material behaviour and produce finite transverse displacement, or geometry change, effects. The damage is characterised as the final or permanent transverse displacement of a plate. The theoretical method predicts values for the maximum permanent transverse displacements which agree reasonably well with the corresponding experimental results generated on aluminium alloy circular, square and rectangular plates. Thus, the equations presented in this article are valuable for preliminary design purposes and for forensic studies, while the experimental data can be used for validating numerical schemes.

Abstract: A fine-grained granitic rock is utilized to study the effect of dynamic strain rates on failure response theoretically. Theoretical investigation employs a model that combines dynamic fracture criterion and damage mechanics theory. We simulated the damage evolution and the strain rate evolution when the rock failed under a dynamic load.

Abstract: Nanostructured ceramic coatings has excellent properties, their industrial application depends not only on their fabrication but also on their precision grinding technology, so it is necessary to study the material removal mechanism in grinding of nanostructured ceramic coatings. This paper presents experimental results on how the grinding processes parameters affect the grinding force ratio and specific grinding energy as well as surface roughness in precision surface grinding of nanostructured WC/12Co (n-WC/12Co) coating and also presents SEM observations of surface and subsurface of n-WC/12Co coating ground under different grinding conditions. Furthermore this paper discusses the material removal mechanism in grinding of n-WC/12Co coatings and gives priority to inelastic deformation instead of brittle fracture, which provides theoretical basis for the precision grinding of nanostructured ceramic coating.