Induced stresses in core-shell latex

The distribution of internal stress in the cross section of the decarburized carbon steel bars, which were normalized, quenched and tempered, or shot-peened, were measured.In this measurement of the internal stress, the dissolution method by acid solution was used in order to remove the outer layers of specimen without any effect of workhardening. The results obtained were as follows:(1) In the outer portion of both the normalized and the heat-treated specimens, containing the decarburized zone, the internal stress acts as tension. This tensile internal stress gets maximum at the surface layer and sharply decreases towards the center of the specimen, till it vanishes at a certain point, which lies at a depth of around 0.5-1.0mm from the surface, and afterwards changes its sign; this compressive internal stress increases towards the center.(2) As the depth decarburized increases, each of these maximum tensile internal stress decreases. The maximum value of this tensile stress is about 52kg/mm2 in the specimen, when the depth of decarburized layer is 0.15mm, and it reduces almost by half when the depth is 0.5mm. The compressive maximum internal stresses in their center zones are about 3-6kg/mm2.(3) The distribution of internal stress in the quenched and tempered steel bar after decarburizing is similer to that of the normalized one. The surface maximum tensile stress is 35kg/mm2 in the specimen having a depth decarburized of 0.15mm, and 15kg/mm2 when the depth is 0.5mm. Thus the maximum tensile stress decreases as the depth of decarburized layer increases.(4) The value of maximum tensile internal stress in the normalized steel bar at each depth decarburized is greater than those of the quenched and tempered bar.(5) The distribution of internal stress in the shot-peened specimen after decarburization is opposite to that of the above mentioned normalized, or heat treated steel bar.The value of maximum compressive internal stress at the surface layer increases as the depth decarburized increases. That is 32kg/mm2 in the specimen with a depth decarburized of 0.05mm and is 60kg/mm2 in the 0.5mm depth specimen.

Internal residual stress measurement on linear friction welding of titanium alloy plates with contour method

Residual stress distributions in 7075 aluminum alloy thick plates with different thicknesses and different quenching speeds were measured. A shape function of stress distribution was proposed based on the internal stress distribution characteristics of aluminum alloy. Using nonlinear regression technology, the function between stress value of key points on internal stress curve and surface stress of the plate was obtained. Based on the measured surface stress, stress value of key points and stress distribution shape, the internal stress distribution can be reconstructed. The experiments show that the model is of good engineering practicality.

This paper investigates the distribution and formation rules of welding residual stress during the process of shield machine hob welding using CO2 arc welding. A corresponding three-dimensional digital model is created using the FEA software to research the distribution of welding residual stress during the single pass wire filling welding. The numerical model of a shield machine hob is verified by the welding experiments. This study utilizes numerical computational methods to describe the causes and changes of welding residual stress and strain during the welding process. According to the calculations, the results indicate that compressive axial residual stress is observed on the outer surface of the hob body near the weld line. Conversely, tensile axial residual stress is evident on the inner surface in contrast. Additionally, both the outer and inner surfaces of the hob body exhibit tensile hoop residual stress. Near the weld line, the upper surface of the hob ring shows tensile transversal and longitudinal residual stresses. The main reason for this phenomenon is that different plastic strains are generated because of the thermal contracting deformation at the various surfaces and internal stress self-balance. Moreover, the internal residual stress distribution of fillet weld is investigated, which is obviously different from the external of fillet weld.

Comprehensive monitoring technique based on electromagnetic radiation and its applications to mine pressure

The influence of ion energy on the magnitude of internal stress, electric conductivity, and surface morphology of nitrogenated carbon coatings on silicon produced by the pulsed vacuum-arc technique has been studied by scanning electron microscopy and scanning probe microscopy. It has been found that an increase in the ion energy with variation in applied acceleration voltage substantially increases the internal compression stress in the forming coating. The ion irradiation results (1) in a considerable inhomogeneity of the internal stress distribution over the coating and (2) in the formation of 15-to 50-nm-high nanoscale islands. Inhomogeneity of the coating conductivity with a minimum on the peaks of the islands has been observed, which indicates the prevalence of tetrahedral bonds between carbon atoms in these regions with sp3 hybridization of atomic electron orbitals (sp3 phases). An explanation of the results has been proposed based on the existing model of the formation of internal stress in coatings prepared under ion irradiation.

Soft actuators have demonstrated potential in minimally invasive surgery (MIS), requiring multiple degrees of freedom and stiffness modulation facilitated by pneumatic antagonistic chambers. However, the hollow central passage in these actuators for single-port surgery complicates the internal stress distribution during the inflation of multiple chambers, making stiffness modulation mechanisms difficult to understand. In this study, a finite element analysis model is developed to explore the combined effect of the internal stress distribution and duct structure on the stiffness modulation in soft actuators equipped with multiple pneumatic antagonistic chambers. A prototype is developed to cross-validate the simulation and examine the effects of various antagonistic chambers on the stiffness modulation. The findings confirm that inflating specific chambers alters the internal stress distribution of the actuator by creating bending moments that influence deformation responses to external loads. These moments impact the stiffness and structure of the hollow central duct by modifying its geometrical moment of inertia and affecting the lengths of the tensile and compressive regions during bending, further influencing the stiffness. The effects of bending moments and the geometrical moment of inertia on stiffness modulation vary across different actuator sections owing to the varying lengths of the tensile and compressive regions during bending. These stiffness modulations affect the tip bending, force, and response time. The study findings provide insights into the mechanism of stiffness modulation for the design of soft actuators for complex MIS.

Stress distribution in the composite electrodes of sulfide all-solid-state lithium-ion batteries

Evaluation of the parameters that characterize the distributions of internal stresses in YAG: Cr 3+ crystals from the data of EPR linewidth

A model has been developed to investigate the effects of a rough elastic indenter in sliding contact with a viscoelastic layer bonded to an elastic semi-infinite plane. The viscoelastic layer is modeled as a one-dimensional Maxwell solid (small strain) while the substrate of the semi-infinite plane is modeled as a two-dimensional elastic half plane. The Fredholm integral equation of the second kind was obtained to determine the contact stresses. The results indicate that the viscoelastic properties of the layer and the velocity of the indenter significantly affect the contact pressure and internal stress distributions. The viscoelastic layer causes the pressure and internal stresses to become nonsymmetrical. High asperity densities reduce the amplitude of maximum shear stress at a fixed depth below the surface. Results are also presented for various coefficients of friction.

Measurement of internal stress in discs

Influence of spinodal decomposition structures on the strength of Fe-Cr alloys: A dislocation dynamics study

This paper deals with the problem of forming a surface roughness profile of a machined surface and a definition of the optimal depth of penetration in ball burnishing which would allow minimization of surface roughness. The assumptions, which have been numerically and experimentally verified, claim that maximum surface quality, i.e., minimum surface roughness, Ra, is achieved when the depth of ball penetration into the workpiece material is approximately equal to the maximum peak height, Rp. For the purpose of numerical simulations, a surface roughness model based on milling kinematics was used. Numerical simulations and the used roughness model support the claim that penetrating with a stiff tool up to the mean line of the roughness profile yields best surface quality. The authors maintain that ball penetrations, which exceed Rp, cannot significantly improve surface quality. Furthermore, the phenomenon of profile peak deformation is substantially clarified. The analysis of internal stresses within the workpiece after ball burnishing allowed a relationship to be established between internal stress distribution along the depth of the hardened layer and ball penetration depth.

The quality traits of a single grain kernel can give index to the overall quality of agrain bulk, because it is individual kernels that comprise a grain bulk. Therefore, the single-kernel drying behavior is important to understand the overall quality of grain. A Matlab andVisual C++ based software package was developed in this study for describing single-kerneldrying, tempering and internal stress analysis. Non-linear and transient partial differential heatand mass transfer equations describing the single kernel drying and tempering processes weresolved using the finite element method. Temperature- and moisture-dependent viscoelasticproperties were applied to the stress analysis of a single rice kernel. A graphical user interface,and 2D/3D graphics for temperature, moisture content and stress changes were developed. Thesimulation results were validated by thin-layer drying data and subsequent temperingexperiments of rough rice. This simulation tool can be used for predicting temperature, moisturecontent and internal stress distribution in a single kernel.

Basaltic shield volcanoes most commonly form as intraplate volcanic ocean islands that arise fromthe ocean floor and continue to grow above the sea water level to formgigantic volcanic edifices. The volcanic edifice evolution and the internal stress distribution may be influenced by the water load of the surrounding ocean. We therefore investigate how the presence of an ocean affects the internal stress of a volcanic edifice and thus magma propagation by means of axisymmetric elastic models of a volcanic edifice overlying an elastic lithosphere. We designed a volcanic edifice featuring a height of ∼6,000m and a radius of ∼ 60 km which was build up either instantaneously or incrementally, i.e., by emplacing new layers of equal volumes on top of each other. The latter was done in a way that the resulting stress and edifice geometry from one step served as the initial condition of the subsequent step. Thus, each new deposit was emplaced on an already deformed and stressed model layer. The ocean load was simulated using a boundary condition at the surface of the model. For the instantaneous volcano growth scenario, different water levels were investigated, while for the incrementally growing volcano the water level was fixed to 4,000m. We employed both half-space and flexural models and compared the deformation of the volcanic edifice, as well as its internal stress orientation and magnitude with and without applying an ocean load. Our results show major differences in the resulting state of stress between an instantaneous and an incrementally built volcanic edifice. Further, our results imply that stress orientations and types of potential magma intrusions within the volcano as well are influenced by the loading effect of an ocean. Ocean loading reduces the effective load magnitude of an edifice via a buoyancy effect, reducing edifice stress magnitudes and substrate subsidence. Ocean loading also adds vertical compression to edifices; in half-space models, this addition reinforces the existing principal stress orientations and increases the differential stress, whereas in flexuralmodels, ocean loading reduces the differential stress and favors re-orientation of principal stresses within the edifices. Our results therefore provide new insights into the state of stress and deformation within the edifices of basaltic ocean island volcanoes with significant implications for magma ascent and eruption and edifice construction.