Evaluation Of Strain Distribution Research Articles

Evaluation of strain distribution in gradually inclined sandy soil ground caused by liquefaction

Evaluation of strain distribution in gradually inclined sandy soil ground caused by liquefaction

Characterisation of Diffuse and Local Necking of Aluminium Alloy Sheets using DIC Technique

This paper introduces a new method for the characterisation of the boundary of diffuse and local necking based on DIC measurements during tensile tests. A series of images illustrate the extension of diffuse necking and show the occurrence of local necking as well. The evaluation of strain distribution gives the exact description of processes using both time dependent and non-dependent methods.

Determination of Forming Limits in Sheet Metal Forming Using Deep Learning.

The forming limit curve (FLC) is used to model the onset of sheet metal instability during forming processes e.g., in the area of finite element analysis, and is usually determined by evaluation of strain distributions, derived with optical measurement systems during Nakajima tests. Current methods comprise of the standardized DIN EN ISO 12004-2 or time-dependent approaches that heuristically limit the evaluation area to a fraction of the available information and show weaknesses in the context of brittle materials without a pronounced necking phase. To address these limitations, supervised and unsupervised pattern recognition methods were introduced recently. However, these approaches are still dependent on prior knowledge, time, and localization information. This study overcomes these limitations by adopting a Siamese convolutional neural network (CNN), as a feature extractor. Suitable features are automatically learned using the extreme cases of the homogeneous and inhomogeneous forming phase in a supervised setup. Using robust Student’s t mixture models, the learned features are clustered into three distributions in an unsupervised manner that cover the complete forming process. Due to the location and time independency of the method, the knowledge learned from formed specimen up until fracture can be transferred on to other forming processes that were prematurely stopped and assessed using metallographic examinations, enabling probabilistic cluster membership assignments for each frame of the forming sequence. The generalization of the method to unseen materials is evaluated in multiple experiments, and additionally tested on an aluminum alloy AA5182, which is characterized by Portevin-LE Chatlier effects.

Evaluation of strain distribution on an edentulous mandible generated by cobalt-chromium metal alloy fixed complete dentures fabricated with different techniques: An in vitro study

Statement of problemFixed complete dentures (FCDs) have been used in the treatment of completely edentulous patients for over 40 years. However, few reports have investigated misfit values and strain distribution in the context of FCDs fabricated with new technologies. PurposeThe purpose of this in vitro study was to evaluate misfit values and strain distribution in FCDs and their relation to the fabrication technique of the cobalt-chromium (Co-Cr) metal framework. Material and methodsFour implants were placed in the interforaminal region of a mandibular cast at the bone level. The Co-Cr metal alloy frameworks were fabricated using the following techniques: computer-aided design and computer-aided manufacturing (CAD-CAM), milling from hard blocks, CAD-CAM milling from soft blocks, and direct metal laser sintering (DMLS). The superstructures of equal sizes with acrylic resin bases and acrylic resin denture teeth were fabricated on the Co-Cr metal alloy framework, and a digital microscope was then used to measure the misfit between the abutments and the implants. The stress formed after the application of torque was measured with a strain-gauge stress analysis technique. Data were statistically analyzed using 1-way ANOVA and the Tukey Honestly Significant Difference test (α=.05). The correlation between the misfit and the strain values was evaluated with the Pearson Correlation test (α=.001). ResultsThe lowest mean misfit values (99 ±17 μm) were observed in the hard block group (P<.05) and the highest in the DMLS group (139 ±29 μm). A statistically significant positive relationship was found between the misfit and the stress distribution after torque application (P<.05). Moreover, the lowest misfit group, hard blocks, had the lowest mean strain values (81.1 ±54 MPa) after torque application. ConclusionsWithin the limitations of this in vitro study, the fabrication technique used for Co-Cr metal alloy frameworks appears to influence the passive fit significantly (P<.05). The hard-block technique was found to be the most precise fabrication technique for Co-Cr metal alloy frameworks. A significant relationship was observed between the amount/distribution of misfit and the strain on the FCD (P<.05).

Evaluation of Strain Distribution in Bone around Implant in Treatment Design of Overdentures Using Computer and Modeling of Finite Elements

Introduction: Introduction: Few studies have investigated the distribution of stress around implants. In this study the distribution of stress in bones around implants was investigated in five overdenture (OD) treatment designs including OD-1, OD-2, OD-3, OD-4 and OD-5. Materials and methods: The Catia modeling software was used in order to simulate the tooth/implant model and bone. First, the borders of cancellous and cortical bone in each section of the CT images were attained by Photoshop software. Then, modeling softwares SolidWorks and NUMBER were applied to make the final three-dimensional model of jaw. Finally, the amount of stress on the surface of bone/implant was studied by means of stress analysis software (Ansys v11.0). Results: Protrusive movements of implants B and D in OD-1 showed the highest amount of strain, 2435 eµ. Also, high amounts of strain, 1668 and 1557 eµwere observed in OD-1 and OD-2 designs in lateral movements respectively. Conclusion: The bottom line is that no forces to the extent of destruction based on the Ferost model were found for these designs. The highest amount of strain occurred in OD-1 design, which is held in mild overload window. Moreover, the amounts of strain in the rest of designs investigated were in adaptive window.

デジタル画像相関法による溶接部材表面のひずみ分布評価

デジタル画像相関法による溶接部材表面のひずみ分布評価

T0302-2-4 X線トポグラフ法によるSi結晶の歪の分布の評価([T0302-2]高信頼マイクロ・ナノデバイスのための設計・計測技術(2):応力・ひずみ計測)

T0302-2-4 X線トポグラフ法によるSi結晶の歪の分布の評価([T0302-2]高信頼マイクロ・ナノデバイスのための設計・計測技術(2):応力・ひずみ計測)

Study of the relation between evaluation of strain distribution on superconducting coil and mechanical heat generation

In the superconducting Maglev system, on-board superconducting magnets (SCMs) are vibrated at various frequencies according to the train speed by the electromagnetic disturbance which is caused when the train passes over ground coils. Then a mechanical loss is generated inside the inner vessel in the SCM. This phenomenon increases the heat load on the cryogenic equipment in the SCM. It has been surmised that the mechanical heat inside the inner vessel is generated by the frictional heat caused by the relative microscopic slips between fasteners and superconducting coil (SC coil). Nevertheless, heat generation mechanisms inside the inner vessel have not been studied sufficiently. In this study, we suggest a hypothesis that the frictional heat generated by the relative microscopic slips between fasteners and a SC coil will be indicated if the calculated strain distribution on the SC coil is evaluated. The results of this study supported this hypothesis.

Evaluation of strain distribution in freestanding and buried lateral nanostructures

A free-standing lateral nanostructure based on GaAs[001] containing a ${\mathrm{Ga}}_{0.97}{\mathrm{In}}_{0.03}\mathrm{As}$ single quantum well and similar structures after the overgrowth with GaAs and AlAs, respectively, have been investigated by high-resolution x-ray grazing incidence diffraction (GID) and conventional x-ray diffraction (HRXRD). The wire shape of the freestanding structure and the lateral density variation in the overgrown samples, were determined by running scans with constant length of the scattering vector (transverse scans) across the grating truncation rods (GTR's) close to the $(2\ifmmode\bar\else\textasciimacron\fi{}20)$ reflection. The in-plane strain distribution became available crossing the $(220)$ GTR's by a scan in the longitudinal direction. Exploiting the capability of GID for depth resolution, the in-plane strain distribution was analyzed for different values of depth below the sample surface. The strain analysis was completed by HRXRD measurements close to the (004) reflection. The x-ray measurements were interpreted in terms of the distorted wave Born approximation applied for GID geometry. The strain distribution is determined by comparing the measured GTR intensities with the corresponding simulations containing the displacement fields obtained from finite-element calculations. At the freestanding wire structure we find laterally compressive strain of about $\ensuremath{\Delta}{a/a}_{\ensuremath{\Vert}}=\ensuremath{-}2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ at the single quantum well (SQW) with a steep strain gradient close to the wire side walls. Both overgrown samples show pronounced lateral strain variation within the overgrown layer, which still appears up to the completely planar surface. Within the SQW the in-plane strain is still compressive after GaAs overgrowth and of similar amount compared to the freestanding grating. The strain is increased by about 30% after overgrowth with AlAs. For both overgrown samples the strain gradient near the wire side walls is reduced, but reaches a maximum close to the SQW. Accompanied by the defect passivation, these findings explain the difference in the energy shift of the photoluminescence line between freestanding and overgrown lateral nanostructures.

The Use of Electrical Conductivity for Evaluation of Strain Distribution in the Simple Shear Device

Abstract This study examines the use of the electrical conductivity method for assessment of internal strain distribution in a simple shear specimen as a result of the shearing process. In this proposed technique, which enables one to assess the strain distribution pattern in the specimen, it is shown from a limited study that the strains developed in the simple shear test are not uniformly distributed, as has been suggested by some researchers.