Articles de revues : « Process stresse »

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Ramos, Sandra, et Jorge A. Ramos. « Process of Change and Effectiveness of Family Constellations : A Mixed Methods Single Case Study on Depression ». Family Journal 27, n^o 4 (13 août 2019) : 418–28. http://dx.doi.org/10.1177/1066480719868706.

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Aims: To analyze the process of change and the effectiveness of five sessions of family constellations (FC) using mixed methods in mixed settings (videoconference and in person). To obtain variables associated with processes and results. Methods: Using an exploratory design with mixed methods, this single case study used a triangulation of data: quantitative ( Escala de Ansiedade, Depressão e Stresse-21) and qualitative (the notes from the consultations and the patient’s responses to the Psychotherapeutic Process Data Mining Questionnaire [PPDMQ]). Results: The patient’s symptoms of depression went from a level of severe to normal, and the posttest results persisted after a 3-month follow-up. The severe depression seems to have been mitigated through interventions that promoted contact with reality, self-determination, the psychoemotional establishment of systemic places, and through finding meaning in autobiographical events. Conclusions: This article may encourage further studies that use the PPDMQ to create a metasynthesis and to gauge whether the effectiveness of FC, as a systemic, intergenerational, and integrative psychotherapy, could plausibly contribute to enrich the body of scientific evidence–based psychotherapies and mitigate the global escalation of depression.

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Du, Wen Bo, Xu Dong Wang, Zhao Hui Wang et Shu Bo Li. « Nano-Crystalline Structure in Mg₂Si/Mg-2.5Er-5Zn Composite on the Route of Repeated Plastic Working Process ». Materials Science Forum 667-669 (décembre 2010) : 635–39. http://dx.doi.org/10.4028/www.scientific.net/msf.667-669.635.

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The Mg-5Zn-2.5Er matrix composite reinforced with the in-situ synthesized Mg2Si second phase particles was fabricated via repeated plastic working (RPW) process. The microstructures and the nanocrystals in the composite have been investigated using transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HREM) and energy dispersive X-ray (EDX). Great deals of nanocrystals were found in the matrix, and they were around the in-situ synthesized Mg2Si. The HREM analysis showed that the size of nanocrystals was in the range of 5-10 nm, and the difference in their crystallographic orientation was bigger than 15°. It is suggested that the formation of nanocrystals in the matrix is attributed to the RPW deformation process and to the intensive stresse fields around the in-situ synthesized Mg2Si particles, which suppress the growth of nanocrystals by forming nonequilibrium grain boundaries containing disordered dislocation networks and junction disclinations.

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Ли, Я. Ц., et Д. Х. Чжан. « Распределение локальных напряжений в волокнисто-армированных композитах с учетом термических напряжений отверждения ». Механика композитных материалов 57, n^o 5 (octobre 2021) : 959–74. http://dx.doi.org/10.22364/mkm.57.5.11.

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В силу различия коэффициентов термического расширения и эффективных модулей упругости материалов волокна и матрицы в композитах в ходе отверждения от высокой температуры изготовления до комнатной возникают концентрации локальных напряжений. Для оценки влияния остаточных термических напряжений на распределение локальных напряжений в композитах разработали высокоточную микромасштабную модель. Полученные численные результаты показали, что остаточные термические напряжения не вызывают пластические деформации в матрице.

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Hwang, Young-In, Geonwoo Kim, Yong-Il Kim, Jeong-Hak Park, Man Yong Choi et Ki-Bok Kim. « Experimental Measurement of Residual Stress Distribution in Rail Specimens Using Ultrasonic LCR Waves ». Applied Sciences 11, n^o 19 (7 octobre 2021) : 9306. http://dx.doi.org/10.3390/app11199306.

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Longitudinal critically refracted (LCR) waves are considered bulk longitudinal waves and penetrate into an effective depth beneath the surface parallel to the material surface. Such LCR waves can be employed to measure residual stresses because the acoustoelastic effect is the basis for ultrasonic residual stress measurements. This effect is described by the relationship between change of wave travel time and stress applied when such waves propagate in a stressed medium. In this paper, stresses applied in a rail were evaluated by using a developed LCR probe. With this transducer, it was verified how the difference in the arrival times of the LCR waves showed a trend as the tensile stresses increased. The acoustoelastic coefficients were calculated using the relationship between the stresses and the travel times, and the residual stresses of the used rails were measured using these coefficients. In addition, the difference in residual stress distribution according to the characteristics of the wheel-rail contact surface was analyzed from the obtained residual stress value. It was concluded that this non-destructive evaluation technique using LCR waves could be employed for accurate stress measurement of rails because differences in stress applied to the rail can be detected.

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Xie, Huibing, Bing Han, Wutong Yan et Peng Jiang. « Statistical Inversion Approach for Stress Estimation Based on Strain Monitoring in Continuously Pre-Stressed Concrete Beams ». Applied Sciences 11, n^o 21 (29 octobre 2021) : 10161. http://dx.doi.org/10.3390/app112110161.

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Stress is one of the most important physical indexes reflecting the mechanical behavior of concrete structures. In general, stress in structures cannot be directly monitored and can only be estimated through an established model of stress and strain. The accuracy of the estimated stress depends on the rationality of the established model for stress and strain. As the strain measured by sensors contains creep, shrinkage, and elastic strain, it is difficult to establish an analytical model for strain and stress. In this paper, a statistical inverse method was utilized to estimate the stress in continuously pre-stressed concrete beams based on the monitored strain. Stress in the beams and the model uncertainty factors were treated as model parameters. A linear-simplified method was adopted to determine the prior distribution of the stresses. The posterior distribution of the stresses at different locations during bridge construction can be obtained by the proposed method. A continuously pre-stressed concrete beam bridge was taken as the case study to verify the effectiveness of the proposed method. Additionally, the constitution of the total strain in the different construction stages was calculated. It was concluded that the creep strain is the dominant part of the total strain.

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LEONTYEV, V. V., et E. V. KONDRATOVA. « MODELING OF THE CONTACT LAYER IN THE STUDY OF THE STEEL WIRE DRAWING PROCESS ». Fundamental and Applied Problems of Engineering and Technology, n^o 4 (2021) : 113–17. http://dx.doi.org/10.33979/2073-7408-2021-348-4-113-117.

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Using the COMSOL MULTIPHYSICS software, the problem of the stress-strain state of a steel wire during drawing is solved by the finite element method. A special contact layer is introduced to describe the contact between the wire and the matrix. It consists of a material whose modulus of longitudinal elasticity in the direction perpendicular to the contacting parts coincides with the modulus of longitudinal elasticity of the matrix or wire, and in the other direction is small, as is the shear modulus. During the calculation, the fields of radial stresses, axial stresses and equivalent stresses are obtained. The results of solving the problem allow us to proceed to the study of residual stresses after drawing, as well as to study the influence of various drawing parameters on the stressed state of the wire.

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Grbović, Aleksandar, Aleksandar Sedmak, Abdulgasem Sghayer et Katarina Čolić. « Assessment of the integrity and life of welded panel using local stresses ». Zavarivanje i zavarene konstrukcije 67, n^o 1 (2022) : 11–19. http://dx.doi.org/10.5937/zzk2201011g.

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Relevant local characteristics of fatigue loading are the largest stress amplitudes in the related mean stress values. They should be determined for the whole components. The relevant material properties are then compared with the stresses to assess integrity and life of a panel, made of Al allow, with welded stringers. To determine the maximum stresses the Finite Element Method was used.

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Kuo, M. K., et H. T. Lee. « Inversion of Residual Stress ». Journal of Mechanics 17, n^o 2 (juin 2001) : 103–8. http://dx.doi.org/10.1017/s1727719100003178.

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ABSTRACTA technique for inverting residual stress based on a theory of acoustoelasticity is presented. A general incremental constitutive relation is first derived for a pre-stressed material subjected to an additional infinitesimal elastic deformation. The theory is then employed on using ultrasonic means to evaluate residual stresses of residually stressed materials. The residual stresses are assumed to be homogeneous in materials as usual. The only major assumption in this formulation is that the additional deformations caused by ultrasonic evaluating process are infinitesimal and elastic. No assumption on the origin of residual stresses is needed, nor the assumption on the possible existence of “natural state” of the materials. Successful inversion of residual stresses are demonstrated through a preliminary numerical experiment.

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Zhichao Jia, Zhichao Jia, Tingzhong Zhang Tingzhong Zhang, Huazhong Zhu Huazhong Zhu, Zewen Li Zewen Li, Zhonghua Shen Zhonghua Shen, Jian Lu Jian Lu et Xiaowu Ni Xiaowu Ni. « Stress damage process of silicon wafer under millisecond laser irradiation ». Chinese Optics Letters 16, n^o 1 (2018) : 011404. http://dx.doi.org/10.3788/col201816.011404.

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Stone, B. M., I. J. Jordaan, J. Xiao et S. J. Jones. « Experiments on the damage process in ice under compressive states of stress ». Journal of Glaciology 43, n^o 143 (1997) : 11–25. http://dx.doi.org/10.3189/s002214300000277x.

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AbstractDuring ice-structure interaction, ice will fail in a brittle manner dominated by two processes. The first corresponds to the formation of macrocracks and the consequent spalling-off of large ice pieces. The second includes an intense shear-damage process in zones, termed critical zones, where high pressures are transmitted to the structure. The shear-damage process results in microstructural changes including microcrack formation and recrystallization. A range of tests on laboratory-prepared granular ice have been conducted to determine the fundamental behaviour of ice under various stress states and stress history, particularly as it relates to changes in microstructure. The test series was designed to study three aspects: the intrinsic creep properties of intact, undamaged ice; the enhancement of creep and changes in microstructure due to damage; and the effects of different stress paths. Tests on intact ice with triaxial confining pressures and low deviatoric stresses, aimed at defining the intrinsic creep response in the absence of microcracking, showed that an accelerated creep rate occurred at relatively low deviatoric stresses. Hence, a minimum Creep rate occurred under these conditions. Recrystallization to a smaller grain-size and void formation were observed. Ice damaged uniaxially and triaxially prior to testing showed enhancement of creep under both uniaxial and triaxial loading conditions Creep rates in triaxially damaged ice were found to be non-linear with high deviatoric stresses, corresponding to a power-law dependence of creep rate. Uniaxially damaged specimens contained microcracks parallel to the stressed direction which tended to close under triaxial confinement. Damage under triaxial conditions at low confining pressures produced small recrystallized grains near zones of microcracking. At high confining pressures, a fine-grained recrystallized structure with no apparent cracking was observed uniformly across the specimen. The recrystallization process contributes significantly to the enhanced creep rates found in damaged specimens.

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Stone, B. M., I. J. Jordaan, J. Xiao et S. J. Jones. « Experiments on the damage process in ice under compressive states of stress ». Journal of Glaciology 43, n^o 143 (1997) : 11–25. http://dx.doi.org/10.1017/s002214300000277x.

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AbstractDuring ice-structure interaction, ice will fail in a brittle manner dominated by two processes. The first corresponds to the formation of macrocracks and the consequent spalling-off of large ice pieces. The second includes an intense shear-damage process in zones, termed critical zones, where high pressures are transmitted to the structure. The shear-damage process results in microstructural changes including microcrack formation and recrystallization. A range of tests on laboratory-prepared granular ice have been conducted to determine the fundamental behaviour of ice under various stress states and stress history, particularly as it relates to changes in microstructure. The test series was designed to study three aspects: the intrinsic creep properties of intact, undamaged ice; the enhancement of creep and changes in microstructure due to damage; and the effects of different stress paths. Tests on intact ice with triaxial confining pressures and low deviatoric stresses, aimed at defining the intrinsic creep response in the absence of microcracking, showed that an accelerated creep rate occurred at relatively low deviatoric stresses. Hence, a minimum Creep rate occurred under these conditions. Recrystallization to a smaller grain-size and void formation were observed. Ice damaged uniaxially and triaxially prior to testing showed enhancement of creep under both uniaxial and triaxial loading conditions Creep rates in triaxially damaged ice were found to be non-linear with high deviatoric stresses, corresponding to a power-law dependence of creep rate. Uniaxially damaged specimens contained microcracks parallel to the stressed direction which tended to close under triaxial confinement. Damage under triaxial conditions at low confining pressures produced small recrystallized grains near zones of microcracking. At high confining pressures, a fine-grained recrystallized structure with no apparent cracking was observed uniformly across the specimen. The recrystallization process contributes significantly to the enhanced creep rates found in damaged specimens.

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12

Solodov, A. A., E. A. Solodova et T. G. Trembach. « Stochastic Model of Emotional Stress Development in the Educational Process ». Statistics and Economics 19, n^o 5 (12 novembre 2022) : 59–67. http://dx.doi.org/10.21686/2500-3925-2022-5-59-67.

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The aim of the study is the development of mathematical models that describe the reaction of the individual to the occurrence of stresses of various nature, including those that appear during the implementation of the educational process. The complexity of developing such a model is confirmed by the lack of theoretical results to substantiate the classic experiments of Holmes and Rae on the effect of stress on personality. In this regard, the task is to develop such a mathematical model that would allow not only to give a theoretical explanation of the experimental results used in the Holmes and Rae stress calculator, but also to become a tool for studying the effect of stress on a person in other conditions, including in the process of educational activities of both the teacher and the learner.The research method consists in a mathematical description of the process of occurrence of stresses that develop over time, and it is believed that stresses occur at random times and are characterized by relative stress values indicated in the classical table of Holmes and Rae. The need to involve these results is that they allow us to confirm the correspondence of the developed theoretical mathematical models to already known practical results. The following main assumptions are accepted in the paper. It is believed that a person is exposed to stresses that can occur at random localized points in time and are interpreted as a sequence of points on the time axis, the number and location of which is random. The response of a person to a particular stress is described by a decreasing exponential function of three arguments – current time, random time of stress occurrence, and stress magnitude. The reaction of the individual to a sequence of stresses is the sum of the responses of the person to individual stresses, i.e. it is assumed that the personality exhibits the properties of linearity. In the process of developing a mathematical model, the distribution of the number of random stresses is substantiated according to the Poisson law, which is used to describe the occurrence of random events with a distinct discreteness. The paper introduces one of the key indexes - the coefficient of emotional load, equal to the ratio of the mathematical expectation of everyday stressful background and the mathematical expectation of the sum of this background and additional stress. The response of a person to a particular stress is described by an exponential response function widely used in natural science applications. The total relative value of processed, experienced, random relative values of stress, as well as their non-random mathematical expectations, is introduced into consideration.The new results of the study are: – development of a stochastic mathematical model for the development of stresses over time, depending on the parameters included in the model. It is shown that the behavior of a person’s reaction to stress, predicted by a mathematical model, corresponds to the previously mentioned experimental results. – a study of the behavior in time of a person’s reaction to stress for a situation that was not previously considered and in which the person is affected by a single stress of great intensity, as well as regular emotional imposition.In conclusion, it is noted that the developed model not only makes it possible to theoretically explain the experimental data, but also significantly expand the scope of the studied effect of stress on personality. Thus, it turned out to be possible to predict the impact of a single impact, as well as to indicate a way to account for periodic intentional exposure (emotional suppression). In addition, the results can be used in the study of emotional stresses in the educational process in order to predict and consider them in practical activities.

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ZHAO, GUIPING, SANG-KYO LEE et CHONGDU CHO. « EFFECT OF COMPRESSIVE RESIDUAL STRESS INDUCED DURING FABRICATING PROCESS IN THE CORE OF CLAMPED SANDWICH PLATE UNDER SHOCK LOADING ». International Journal of Modern Physics B 22, n^o 09n11 (30 avril 2008) : 1195–200. http://dx.doi.org/10.1142/s0217979208046530.

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Sandwich panels can be manufactured in many ways like lamination press, closed mold fabrication, and vacuum bag compaction. During manufacturing, the core and the sheets are attached under certain applied pressure and temperature, associated with a deformation and stress remaining in the sandwich core. This study presents an evaluation of the compressive residual stress effect of the core which occurs during the localized shock loading at the mid-span of a clamped sandwich plate. We simulate such a square lattice core sandwich plate by commercial finite element code, ABAQUS/Explicit. We apply uniform distributed loading on upper face sheet and temperature difference occurred during the manufacturing process is taken here before the impact simulation step. These loadings induce certain amount of residual stresses in core structure of sandwich panel. The computational result from non-residual stress case is verified by comparing with the results of published experimental data on similar investigation. In addition, the effect of existing residual stress at core is analyzed. We also compare the dynamic responses of two clamped sandwich plates with and without pre-stressed core. And impact resistance of sandwich panel is explained in the view of energy capacity. Results show that the shock loading behavior of sandwich panel depends on its manufacturing process and panels with compressive residual stresses have less deformation and high impact energy absorption characteristics.

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SAMAN, Alias Mohd, Takashi UEDA, Kazuto FUJISAWA, Tatsuaki FURUMOTO, Akira HOSOKAWA et Tomohiro KOYANO. « 509 Temperature and Acoustic Emission Monitoring in Thermal Stress Cleaving Process ». Proceedings of Conference of Hokuriku-Shinetsu Branch 2014.51 (2014) : _509–1_—_509–2_. http://dx.doi.org/10.1299/jsmehs.2014.51._509-1_.

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Daniewicz, S. R., et S. D. Cummings. « Characterization of a Water Peening Process ». Journal of Engineering Materials and Technology 121, n^o 3 (1 juillet 1999) : 336–40. http://dx.doi.org/10.1115/1.2812383.

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A traversing water jet was used to impact the surface of 1100 series aluminum specimens in an effort to generate compressive residual stresses on the surface. Stresses induced by the water peening operation were measured using X-ray diffraction, and compressive stress increases as large as 60 percent of the monotonic yield strength resulted. Surface roughness and hardness were also measured. Finite element modeling of a stationary water jet impinging on an elastic-plastic half-space was performed to characterize the water peening process. Surface residual stresses were found to be a result of sub-surface plastic deformations.

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Qin, Wen Jie, et Chao Dong. « FEM Simulation of Quenching Process and Investigation of Residual Stresses of Crankshafts ». Key Engineering Materials 626 (août 2014) : 149–54. http://dx.doi.org/10.4028/www.scientific.net/kem.626.149.

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Compressive residual stresses and high hardness introduced by induction quenching are often used to improve the mechanical performance of crankshafts in engines. In this paper, in order to predict the fatigue strength of the crankshafts in a diesel engine accurately, the quenching process and the stress fields of the crankshaft are simulated by finite element method (FEM) and then the residual stresses are obtained. Quenching is a high non-linear process because of the coupling of the temperature, phase transformation and stress/strain fields. The transient temperature field is firstly solved using a quasi-coupling method to simulate the relationship of the temperature and the phase transformation. Based on the results of the temperature and phase transformation fields, the thermo-elastic-plastic analysis is then carried out to calculate the stress fields including the thermal stresses and the phase transformation stresses. At last the residual stress distribution at the room temperature is obtained.

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Saan, Marieke, Lidewij Bollen et Maarten Kunst. « Het werk van de familierechercheur : een bron van stress of een bron van persoonlijke groei ? » PROCES 94, n^o 3 (juin 2015) : 192–207. http://dx.doi.org/10.5553/proces/016500762015094003005.

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Wu, Zhu, Jian Lu et Yifan Guo. « A Study of Process-Induced Residual Stress in PBGA Packages ». Journal of Electronic Packaging 122, n^o 3 (8 décembre 1999) : 262–66. http://dx.doi.org/10.1115/1.1285983.

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Process-induced residual stresses can play a significant role in the reliability of electronic components and packages. In this paper, a practical method is developed to determine residual stresses for electronic packaging. In this method, blind holes are drilled into the specimens and relationships are established, between the released surface displacements and the corresponding residual stress, by introducing a set of calibration coefficients. A multilayer 3D-FEM model is established to determine the relevant calibration coefficients. This methodology, which combines moire´ interferometry and the incremental hole drilling method, can provide an accurate determination of residual stresses in materials and structures by precisely controlled incremental blind-hole drilling and an accurate determination of the surface in-plane displacement fields in the hole drilling region. The methodology is implemented by investigating the residual stress in the Plastic Ball Grid Array (PBGA) packages. The tensile residual stresses are determined in both the plastic molding compound and the glass/epoxy laminate chip carrier. The method is accurate, simple, convenient, and practical. More applications, in residual stress determinations and in process evaluations in electronic packaging, are anticipated. [S1043-7398(00)00103-1]

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Kozlowski, T. T. « Tree Growth in Response to Environmental Stresses ». Arboriculture & ; Urban Forestry 11, n^o 4 (1 avril 1985) : 97–111. http://dx.doi.org/10.48044/jauf.1985.023.

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Shade trees are subjected to a wide variety of environmental stresses which decrease growth and cause injury and mortality. Although trees often are classed as either stressed or unstressed, all trees are periodically stressed by unfavorable environmental conditions above or below ground, and often both. Exposure of trees to some stresses also predispose them to the effects of other stresses. Healthy trees require adequate supplies and balances of carbohydrates, growth regulating hormones, water, and minerals. Environmental stresses, alone or in combination, reduce tree growth by setting in motion a series of complex physiological events leading to deficiencies of these essential substances. Explaining growth reduction of stressed trees by correlating growth with a single physiological process such as photosynthesis oversimplifies the causal events involved. Examples are given of some of the mechanisms by which drought, high and low temperature, mineral deficiency or excess, and environmental pollutants reduce growth and injure shade trees. Arborists can make important contributions in selecting appropriate species, adequately preparing planting sites, and imposing cultural practices that will minimize exposure of trees to stress factors.

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Węglowski, Marek Stanisław, Piotr Sedek et Carter Hamilton. « Experimental and Numerical Analysis of Residual Stress in Cast Aluminum Alloy after FSP Process ». Key Engineering Materials 651-653 (juillet 2015) : 1563–68. http://dx.doi.org/10.4028/www.scientific.net/kem.651-653.1563.

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The effect of FSP modification of cast aluminum alloy AlSi9Mg on residual stress are presented. The numerical results are compared with the residual stresses experimentally measured by the trepanation method. Experimental results show that the residual tensile stresses are higher on the advancing side than on the retreating side. The simulation successfully captures the asymmetric behavior of the residual stress profile, and the predicted maximum residual stress values show relatively good agreement with the experimental values. The simulated profile, however, is more narrow than the experimental profile, yielding a smaller region of residual tensile stresses around the process zone than experimentally observed

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Joshi, Jaya, Ghulam Hasnain, Taylor Logue, Madeline Lynch, Shan Wu, Jiahn-Chou Guan, Saleh Alseekh, Alisdair R. Fernie, Andrew D. Hanson et Donald R. McCarty. « A Core Metabolome Response of Maize Leaves Subjected to Long-Duration Abiotic Stresses ». Metabolites 11, n^o 11 (22 novembre 2021) : 797. http://dx.doi.org/10.3390/metabo11110797.

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Abiotic stresses reduce crop growth and yield in part by disrupting metabolic homeostasis and triggering responses that change the metabolome. Experiments designed to understand the mechanisms underlying these metabolomic responses have usually not used agriculturally relevant stress regimes. We therefore subjected maize plants to drought, salt, or heat stresses that mimic field conditions and analyzed leaf responses at metabolome and transcriptome levels. Shared features of stress metabolomes included synthesis of raffinose, a compatible solute implicated in tolerance to dehydration. In addition, a marked accumulation of amino acids including proline, arginine, and γ-aminobutyrate combined with depletion of key glycolysis and tricarboxylic acid cycle intermediates indicated a shift in balance of carbon and nitrogen metabolism in stressed leaves. Involvement of the γ-aminobutyrate shunt in this process is consistent with its previously proposed role as a workaround for stress-induced thiamin-deficiency. Although convergent metabolome shifts were correlated with gene expression changes in affected pathways, patterns of differential gene regulation induced by the three stresses indicated distinct signaling mechanisms highlighting the plasticity of plant metabolic responses to abiotic stress.

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Li Kangmei, 李康妹, 何幸哲 He Xingzhe, 蔡宇 Cai Yu et 胡俊 Hu Jun. « 搅拌摩擦焊与激光冲击复合工艺的应力场仿真 ». Chinese Journal of Lasers 48, n^o 18 (2021) : 1802008. http://dx.doi.org/10.3788/cjl202148.1802008.

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Yujie Fan, Yujie Fan, Jianzhong Zhou Jianzhong Zhou, Shu Huang Shu Huang, Jinrong Fan Jinrong Fan, Bin Gao Bin Gao et Wei Zhu Wei Zhu. « Residual stress induced by multi-micro laser shock peening under overlapping process ». Chinese Optics Letters 10, s1 (2012) : S11408–311410. http://dx.doi.org/10.3788/col201210.s11408.

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Jogaiah, Satisha, Sahadeo D. Ramteke, Jagdev Sharma et Ajay Kumar Upadhyay. « Moisture and Salinity Stress Induced Changes in Biochemical Constituents and Water Relations of Different Grape Rootstock Cultivars ». International Journal of Agronomy 2014 (2014) : 1–8. http://dx.doi.org/10.1155/2014/789087.

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Ten grape rootstocks were subjected to moisture and salinity stress in two separate experiments. The influence of these stresses on gas exchange, water relation, and biochemical parameters was monitored at various stages of stress cycle. Both stresses indicated significant changes in the physiological and biochemical parameters studied. Some biochemical constituents increased by several folds in few rootstock cultivars which also recorded increased osmotic potential suggesting their role in osmotic adjustment. Some of the rootstock cultivars such as 110R, 1103P, 99R, Dogridge, and B2/56 recorded increased phenolic compounds under stressed conditions. The same rootstock also recorded increased water use efficiency. The increased accumulation of phenolic compounds in these cultivars may indicate the possible role of phenolic compounds as antioxidants for scavenging the reactive oxygen species generated during abiotic stresses thus maintaining normal physiological and biochemical process in leaves of resistant cultivars.

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Zhao, X. C., Y. D. Zhang et Y. J. Ma. « Finite Element Analysis of Vibratory Stress Relief Process ». Applied Mechanics and Materials 88-89 (août 2011) : 623–27. http://dx.doi.org/10.4028/www.scientific.net/amm.88-89.623.

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The process of stress vibratory relief is gaining more and more weight as manufacturing process. This is mainly due to the fact that vibratory stress relief has the advantage of low energy consumption and dramatic reduction of pollution to the environment in respect to traditional thermal stress relief process. A finite element model is developed for the simulation of vibration stress relief (VSR) process. A cantilever beam was pre-stressed and then subjected to transverse cyclic force to see the effect of vibration frequency, time and amplitude on the reduction of residual stress. It was shown that the excitation frequency and amplitude of the load on the beam had great effect on the reduction of the residual stress. Increasing vibration time can decrease the magnitude of residual stress, but its influence reduces greatly after several cycles.

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Li, Xiao Ke, Jian Liu, Zhi Hao Wang et Peng Fei Han. « Testing and Control for Strands Embedded in Annular Concrete Foundation Beam of Steel Archaize Tower ». Applied Mechanics and Materials 238 (novembre 2012) : 643–47. http://dx.doi.org/10.4028/www.scientific.net/amm.238.643.

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Combined with the design and construction of annular pre-stressed concrete foundation beam of Tiantang Site Protection Exhibition Project in Luoyang, China, this paper introduces the test process of frictional lose for annular strands. The calculation method is given to deal with the original data to get the friction coefficient of the strands. The controlling parameters such as control tensioning stress and theoretical elongations of strands are advised. The rational pre-stressing process and key indexes are confirmed by the comparison of test and theoretical circumferential stresses of the foundation beam. It is reasonable to fulfill the design requirements by strict controlling in the fields. It is believed that the process and method in this paper would give some reference for the construction of similar annular pre-stressed concrete structures.

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Costa, Ane Catarine Tosi, Mariano Russo, A. Alberto R. Fernandes, James R. Broach et Patricia M. B. Fernandes. « Transcriptional Response of Multi-Stress-Tolerant Saccharomyces cerevisiae to Sequential Stresses ». Fermentation 9, n^o 2 (20 février 2023) : 195. http://dx.doi.org/10.3390/fermentation9020195.

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During the fermentation process, yeast cells face different stresses, and their survival and fermentation efficiency depend on their adaptation to these challenging conditions. Yeast cells must tolerate not only a single stress but also multiple simultaneous and sequential stresses. However, the adaptation and cellular response when cells are sequentially stressed are not completely understood. To explore this, we exposed a multi-stress-tolerant strain (BT0510) to different consecutive stresses to globally explore a common response, focusing on the genes induced in both stresses. Gene Ontology, pathway analyses, and common transcription factor motifs identified many processes linked to this common response. A metabolic shift to the pentose phosphate pathway, peroxisome activity, and the oxidative stress response were some of the processes found. The SYM1, STF2, and HSP genes and the transcription factors Adr1 and Usv1 may play a role in this response. This study presents a global view of the transcriptome of a multi-resistance yeast and provides new insights into the response to sequential stresses. The identified response genes can indicate future directions for the genetic engineering of yeast strains, which could improve many fermentation processes, such as those used for bioethanol production and beverages.

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Kostov, Vladimir, Jens Gibmeier et Alexander Wanner. « Laser Surface Hardening of Steel : Effect of Process Atmosphere on the Microstructure and Residual Stresses ». Materials Science Forum 772 (novembre 2013) : 149–53. http://dx.doi.org/10.4028/www.scientific.net/msf.772.149.

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The effect of processing atmosphere on the microstructure and residual stresses are studied for laser surface hardening on steel samples of grade AISI 4140. Samples were hardened in air, vacuum and inert gas atmosphere (Helium) by means of a stationary laser beam. A high-power diode laser (HPDL) system was used in combination with a custom-designed process chamber. Residual stress distributions in lateral and in depth direction were analysed after laser processing by means of X-ray diffraction according to the well known sin² - method. X-ray residual stress analyses were supplemented by microscopic investigations of the local microstructure. The results indicate a widening of the compressive stressed region in lateral as well as in depth direction by surface hardening in inert gas atmosphere compared to laser surface hardening in air or vacuum atmosphere. This is due to the local heating flux distribution during the laser assisted heat treatment which is strongly affected by the processing atmosphere an leads to an extension of the hardening zone when using helium as inert gas.

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Klinger, Leonid, et Eugen Rabkin. « Kirkendall Effect during Grain Boundary Interdiffusion in Polycrystalline Thin Films ». Defect and Diffusion Forum 323-325 (avril 2012) : 49–54. http://dx.doi.org/10.4028/www.scientific.net/ddf.323-325.49.

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We consider the kinetics of chemical interdiffusion along the grain boundaries in stressed thin metal film attached to inert substrate. We show that the kinetics of stress relaxation in the film can be either accelerated or slowed down if compared with the same kinetics in a single-component film, depending on the difference of intrinsic GB diffusion coefficients of the two components. In the case of faster matrix atoms the tensile stress in the film significantly increases beyond its initial value at the beginning of interdiffusion process, while in the case of faster diffuser atoms the compressive stresses develop in the film at the intermediate stages of stress evolution.

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Nawangsih, S. K., et Putri Rismala Sari. « STRES PADA MANTAN PENGGUNA NARKOBA YANG MENJALANI REHABILITASI ». Jurnal Psikologi Undip 15, n^o 2 (20 mai 2017) : 99. http://dx.doi.org/10.14710/jpu.15.2.99-107.

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This is a qualitative phenomenological research aimed to understand stress of a former drug users whose under rehabilitation process. This research focused on factors that influencing and implications due to stresses of former drug users. Data collection method used is the method that used in this research is semi-structured interview, observations by non-participants, checklists, and documentations. Subject in this research determined by the cooperative ability of former drug users whose undergoing rehabilitation, which is three women as participants, at former drug users social rehabilitation office “Mandiri”, Semarang. Through descriptive analysis of data research, factors that making former drug users stressed during rehabilitation process are loss of freedom, the guilty feelings, social affect such as ex-drug users label and other affect which cause worsen the conditions of a former drug users and the stressed level become higher. Furthermore, stress that experienced by the former users will affect their subjective conditions, cognitive behavior, and physiological conditions.

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Hirano, Tatsumi, Daiko Takamatsu, Kosuke Kuwabara, Shuo Yuan Zhang, Takahisa Shobu, Ayumi Shiro et Masugu Sato. « In Situ Stress Measurements during Welding Process ». Materials Science Forum 905 (août 2017) : 137–42. http://dx.doi.org/10.4028/www.scientific.net/msf.905.137.

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Welding technologies are indispensable for fabricating various industrial structures and must be highly reliable. Since tensile residual stresses at surface after welding cause crack progress, it is important to understand how stresses built up during the welding process in order to optimize final residual stresses as reduced tensile or introduced compressive stresses. Therefore, we conducted in-situ measurements of phase transformations, stresses and temperatures during tungsten inert gas (TIG) welding to understand how stresses built up. X-ray diffraction rings were detected per 0.1 sec during TIG welding by using a large-area two-dimensional detector and the accuracy of the stress analysis was estimated to be 8 MPa using the sin2ψ technique. In this paper, we described the phase transformations of ferrite low-carbon rolled steel and the changes in stresses during TIG welding.

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Li, Jinbo, Xiaohui Chen et Xianlong Liu. « Investigation of process parameters and plate local thickening on residual stresses in hot stamping process ». Mechanics & ; Industry 22 (2021) : 18. http://dx.doi.org/10.1051/meca/2021015.

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In this paper, local-thickened plates are adopted for aluminum alloy square cups stamping with relatively low values of residual stresses and small radius at the bottom corner. By utilizing numerical and experimental methods, the effects of process parameters and plate local thickening on the residual stress distribution of hot stamped aluminum alloy square cups are studied. Furthermore, the influence of plate local thickening on the radius of bottom corner of square cups is also investigated. The results showed that with an increase in the forming temperature, blank holder force and die corner radius, residual stresses in hot stamped square cups can be reduced. The same effect can be achieved by decreasing the die entrance radius. As opposed to the flat plates, using local-thickened plates can not only reduce the residual stresses values in hot stamped square cups, but also decrease the radius at the bottom corner of square cups. When the optimized thickening scheme of plate is used, the smaller radius at the bottom corner, the lower residual stresses in the square cups are obtained.

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Azaman, M. D., S. M. Sapuan, Shamsuddin Sulaiman, E. S. Zainudin et Abdan Khalina. « Numerical Simulation on Moulded Thin-Walled Parts via Injection Moulding Process ». Applied Mechanics and Materials 575 (juin 2014) : 73–77. http://dx.doi.org/10.4028/www.scientific.net/amm.575.73.

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The current trend in the industry is to produce thin, light weight, and environmental products. In this project, flat or shallow thin-walled parts were designed and moulded lignocellulosic polymer composites (PP + 50 wt% wood) to visualize the processability via moulding simulation. This studied focused on the filling, shear stress at wall, and in-cavity residual stresses behaviors. The shallow thin-walled part is preferable in moulding PP + 50 wt% wood due to economically in processing, low shear stress distribution and low residual stresses than the flat thin-walled part.

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Dr. S.A.NAYAKAWADI, Dr S. A. NAYAKAWADI. « Existance of Stresses in Sugar Industry Units in Different Stages of the Process ». Indian Journal of Applied Research 4, n^o 6 (1 octobre 2011) : 557–60. http://dx.doi.org/10.15373/2249555x/june2014/173.

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Di Donato, Sara, Lorenzo Donati et Marco Negozio. « Copper Wire Multi-Pass Drawing : Process Modeling and Optimization ». Key Engineering Materials 926 (22 juillet 2022) : 499–510. http://dx.doi.org/10.4028/p-g4wbpz.

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During cold wire drawing process, the drawing stress applied to the wire at the exit of the die must be lower than the material yield stress (including strain-hardening) to avoid wire necking and fracture. Several studies have been developed to investigate and model the stress acting on the wire in the single pass drawing and its dependence on the main process parameters. The aim of this work is to apply an analytical model for the calculation of the drawing stresses during the whole complex multi-pass manufacturing process in industrial environment, considering not only the forces acting in the die but also the driving forces of the rotating capstans (drawing tension and back tension). The drawing of ETP Pure Copper (99.9% in weight), using two industrial multi-pass machines with different reduction ratio sequences, is analysed and then discussed in order to understand the different failure rates. Finally, the study compared step by step, the evolution of the drawing stresses respect to material yield stress when different processing conditions (i.e. change of capstan windings, change of friction conditions in the die and in the capstan) are applied.

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Frerichs, Friedhelm, Yang Lu, Thomas Lübben et Tim Radel. « Process Signature for Laser Hardening ». Metals 11, n^o 3 (11 mars 2021) : 465. http://dx.doi.org/10.3390/met11030465.

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During many manufacturing processes for surface treatment of steel components heat will be exchanged between the environment and the workpiece. The heat exchange commonly leads to temperature gradients within the surface near area of the workpiece, which involve mechanical strains inside the material. If the corresponding stresses exceed locally the yield strength of the material residual stresses can remain after the process. If the temperature increase is high enough additionally phase transformation to austenite occurs and may lead further on due to a fast cooling to the very hard phase martensite. This investigation focuses on the correlation between concrete thermal loads such as temperature and temperature gradients and resulting modifications such as changes of the residual stress, the microstructure, and the hardness respectively. Within this consideration the thermal loads are the causes of the modifications and will be called internal material loads. The correlations between the generated internal material loads and the material modifications will be called Process Signature. The idea is that Process Signatures provide the possibility to engineer the workpiece surface layer and its functional properties in a knowledge-based way. This contribution presents some Process Signature components for a thermally dominated process with phase transformation: laser hardening. The target quantities of the modifications are the change of the residual stress state at the surface and the position of the 1st zero-crossing of the residual stress curve. Based on Finite Element simulations the internal thermal loadings during laser hardening are considered. The investigations identify for the considered target quantities the maximal temperature, the maximal temperature gradient, and the heating time as important parameters of the thermal loads.

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Andrei, Oana Cella, Livia Alice Tănăsescu, Ioana Daniela Tărlungeanu, Magdalena Natalia Dina et Mircea Horia Tierean. « Finite Element Comparative Analysis of Von Mises Stress Levels in Unilateral Removable Partial Denture with and without Distal Implant ». Applied Sciences 12, n^o 10 (19 mai 2022) : 5116. http://dx.doi.org/10.3390/app12105116.

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The aim of this paper is to compare von Mises stress levels and displacements between two possible designs of a class II Kennedy unilateral removable partial denture. Finite element analysis was used to compare two unilateral class II Kennedy removable partial dentures replacing a mandibular second premolar, and first and second molars and with the same design, except a distal implant. The 3D model was created for a mandibular RPD with three artificial teeth and double ball attachment on the abutment teeth and a horizontal ball attachment for the implant, using Autodesk Inventor 2022 software. On the saddle, significant differences appear only when force is applied on the second molar. Association with implant increases von Mises stresses on the acrylic saddle, where displacements values are similar, and decreases von Mises stresses on the muco-osseous support, where displacements values are also similar. Regarding metal reinforcement of the denture, von Mises stress values are greater for forces applied on the second premolar in the implant situation, and smaller for forces applied on the first and second molars. Association with implant decreases von Mises stresses on the metal reinforcement of the denture only if the force is applied distally, on the two molars; in this case, the metal reinforcement is more stressed above the mesial double ball attachment, where displacements values are similar. Regarding the artificial teeth, adding a distal implant does not significantly influence the stress and displacements values, except on the second premolar where the von Mises stresses values are greater, where displacements values are similar. Although an association with an implant increases the risk of fracture for the denture, the results demonstrate that in the posterior area of the edentulous space, the denture exerts less pressure on the mucosa and subjacent bone, protecting the area against resorption.

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Yang, Wu, Wen Juan Yao et Xiao Yu Liu. « Stress Monitoring for the Whole Construction Process of Simply Supported to Continuous T-Beam Bridge ». Applied Mechanics and Materials 71-78 (juillet 2011) : 3954–57. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.3954.

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In order to research on the stress change and influencing factor of whole construction process of simply supported to Continuous system T-beam bridge, combined with Guizhou Bai-long bridge, the stress change is carried out the real time inspection in each construction stage, and the finite element model is established to analyse Stress changes in whole construction process. The monitoring value is more consistent with the theoretical value in each stage , monitoring dates and theoretical calculations showed that pre-stressed is the main factor of stress changes in construction process.Pre-stressed tension in negative moment region has obvious influence on the stress of middle span, the stress of top and bottom plates in wet joints will be equivalent after tendons tension in negative moment Region.

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Kallien, Zina, Sören Keller, Volker Ventzke, Nikolai Kashaev et Benjamin Klusemann. « Effect of Laser Peening Process Parameters and Sequences on Residual Stress Profiles ». Metals 9, n^o 6 (4 juin 2019) : 655. http://dx.doi.org/10.3390/met9060655.

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Laser Peening (LP) is a surface modification technology that can induce high residual stresses in a metallic material. The relation between LP process parameters, in particular laser sequences, as well as pulse parameters and the resulting residual stress state was investigated in this study. The residual stress measurements, performed with the hole drilling technique, showed a non-equibiaxial stress profile in laser peened AA2024-T3 samples with a clad layer for certain parameter combinations. Shot overlap and applied energy density were found to be crucial parameters for the characteristic of the observed non-equibiaxial residual stress profile. Furthermore, the investigation showed the importance of the advancing direction, as the advancing direction influences the direction of the higher compressive residual stress component. The direction of higher residual stresses was parallel or orthogonal to the rolling direction of the material. The effect was correlated to the microstructural observation obtained via electron backscattered diffraction. Additionally, for peening with two sequences of different advancing directions, the study showed that the order of applied advancing directions was important for the non-equibiaxiality of the resulting residual stress profile.

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Lebed, Evgeny V., et Vladimir P. Vershinin. « Stress state of metal dome meridional ribs at different stages of overhang erection process ». Structural Mechanics of Engineering Constructions and Buildings 16, n^o 2 (15 décembre 2020) : 111–21. http://dx.doi.org/10.22363/1815-5235-2020-16-2-111-121.

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Research aim. The aim of the present research was an analysis of a metal ribbed ring-shaped dome metallic ribs stress state at different stages of a skeleton overhang erection process. The considered dome is hemispherical and is assembled bottom-up of individual elements. Due to a varying slope of meridional ribs elements at different relative elevations their stress state changes during mounting. The effect of the overhang erection process onto the stress state of the metal dome meridional ribs has been investigated. The relationship between the stress state of a meridional rib and mounting of each next dome skeleton tier has been established. Methods. A mathematical model of the metal ribbed ring-shaped dome assembled of steel H-shaped elements with rigid connections has been developed. Several extra models corresponding to different skeleton erection stages have been also generated to determine stresses in the meridional ribs at these stages. Response of each dome mathematical model under dead-weight load has been simulated. The obtained values of stresses in the meridional ribs within different models have been compared with corresponding design stresses values. Results. The dependence of the metal dome meridional rib stress state onto the stages of overhang erection process has been plotted. A degree of utilization of ribs steel strength at different erection stages has been represented by diagrams. An estimation of the dome skeleton stress state during overhang erection has been given. Imminence of assembly stresses during overhang erection and their influence onto dome structural reliability has been pointed out.

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Akita, Koichi, Hirotomo Tanaka, Yuji Sano et Shin Ichi Ohya. « Compressive Residual Stress Evolution Process by Laser Peening ». Materials Science Forum 490-491 (juillet 2005) : 370–75. http://dx.doi.org/10.4028/www.scientific.net/msf.490-491.370.

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Microscopic residual stress distribution on laser-irradiated materials was measured using a synchrotron radiation source. Intense laser pulses were irradiated in water to high tensile strength steel and austenitic stainless steel without any surface coating. Residual stress was measured in a laser-irradiated spot (0D), line (1D) and area (2D) on the materials in order to clarify the evolution process of residual stress. Tensile residual stresses were observed in the laser single pulse irradiated spot (0D). In the line (1D) and area (2D) irradiation, however, the tensile residual stress gradually changed into compressive side as the density of irradiated laser pulses increased. In case of laser irradiation in water, resulting residual stress is considered to be the sum of a tensile stress component by thermal effect and a compressive one by plastic deformation due to shock wave. The tensile stress component remains constant even if the laser pulse density increases, because the thermal effect may be reset every pulse, whereas the compressive stress component increases with laser pulse density, until the saturation of plastic deformation. As a result, the surface residual stress changes into compression with increasing the laser pulse density.

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Maryin, S. B., I. K. Andrianov et V. V. Chernomas. « Stress Evaluation in the Blank Critical Region During Extrusion of the Pipe Blank into the Hole ». Journal of Physics : Conference Series 2096, n^o 1 (1 novembre 2021) : 012207. http://dx.doi.org/10.1088/1742-6596/2096/1/012207.

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Abstract The study assessed the stress state of the pipe blank in the process of extrusion into the hole. A finite element formulation of the research problem with the setting of boundary conditions in displacements and surface loading conditions is presented. The calculation of the workpiece was carried out in an elastic formulation using the Nastran engineering analysis application. The assessment of the stress state in the critical region is presented in two approximations with a thickening of the grid in the stress focus area. Based on the results of the distribution of equivalent stresses, an assessment of the unevenness of the stressed state of the workpiece was carried out. The presented study is important because it allows us to predict the appearance of defects in the process of forming a pipe billet during extrusion into a hole, to evaluate the power loading mode.

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Migicovsky, Zoë, et Igor Kovalchuk. « Changes to DNA methylation and homologous recombination frequency in the progeny of stressed plants ». Biochemistry and Cell Biology 91, n^o 1 (février 2013) : 1–5. http://dx.doi.org/10.1139/bcb-2012-0046.

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Plants undergo changes in response to biotic and abiotic stresses that help them adjust and survive. Some of these changes may even be passed on to progeny and eventually lead to adaptive evolution. Transgenerational changes in response to stress include alterations in DNA methylation and changes in homologous recombination frequency (HRF). The progeny of plants that were stressed often show elevated HRF as well as genomic hypermethylation, although specific loci that are beneficial in times of stress may be hypomethylated. One of the possible mechanisms responsible for passing the memory to the progeny involves small interfering RNAs; Dicer-like proteins, DCL2 and DCL3, are in part required for this process. However, while epigenetic modifications are often present in the untreated progeny of stressed plants, they are not usually sustained for multiple unexposed generations. Still, transgenerational inheritance of such changes has already begun to provide evidence for an important role of epigenetics in enhancing stress resistance.

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Chen, Ji Ping, Jian Qing Qian et Sheng Zhi Li. « Influence of Hot Leveling and Cooling Process on Residual Stresses of Steel Plates ». Advanced Materials Research 168-170 (décembre 2010) : 1130–35. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.1130.

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A three-dimensional thermo-mechanical coupled model of hot leveling and cooling processes of the steel plate has been conducted with MSC.Superform software. Four kinds of initial temperature distribution patterns have been determined according to literature. The effects of hot leveling and cooling processes on the transversal and longitudinal residual stresses of the steel plate have been analyzed. The results show that the initial temperature distribution patterns have significant influence on the residual stress of the plate. The more uniform temperature distribution patterns along the width of the plate, the smaller residual stress and also the smaller stress fluctuations. The cooling process has greater effect on the residual stress compared with the hot leveling process. The bigger the temperature gradient along the width of steel plate, the larger the residual stress and its fluctuation is. Through the FEM study, the value and direction of transversal and longitudinal residual stresses can be confirmed quantitatively at various positions along the width and length of plate, which can provide guidance to actual measurement of residual stress.

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Tian, Qian Qian, Jin Duo Ye, Xue Li, Xian Kang Wang, Chun Qiu Zhang et Li Min Dong. « Numerical Simulation to the Process of Damage Evolution of Defect Cartilage ». Applied Mechanics and Materials 397-400 (septembre 2013) : 629–32. http://dx.doi.org/10.4028/www.scientific.net/amm.397-400.629.

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Objective To understand the stresses distribution and process of damage evolution of both matrix and fiber in the defect cartilage under load of compression. The numerical results may provide a reference to both of the design for cartilage alternatives and clinical repair of defect cartilage. Methods The thickness of different layers of cartilage was obtained by a kind of experiment, in which the displacement in different layers zone cartilage under the compression load was obtained by the digital correlation technique. The multi-layer cartilage model with fiber and defect was established by the multi-physics analysis software ANSYS, with the different layers of the cartilage refer to the experimental results. According to the strength condition, the cartilage damage evolution process was simulated by the method of modifying the stiffness of the elements. The influence of the different defect depth to the damage evolution of cartilage was considered in parameter study. Result The simulation results have shown that the stress distribution in matrix was related to the cartilage defect depth. The minimum stress was distributed in the deep areas and below the damage area, stress concentration was located in the both sides of the defect area in the cartilage matrix, and the damaged area developed gradually from surface to deep, the maximum stress located at both sides of defect area. The stress distribution of cartilage fibers related with their location, the compressive stresses are mainly distributed in the middle and deep area, which are greater than those of undamaged. Conclusion In the process of damage evolution, the damaged area gradually developed from the surface to the deep. In the case of defect value of 60%, the maximum equivalent stresses in matrix will be increased in the process of damage evolution; in the case of defect value of 5%, the maximum axial stresses in fibers will be increased in the process of damage evolution.

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Kowalski, Dariusz. « Application of the Mathar Method to Identify Internal Stress Variation in Steel as a Welding Process Result ». Civil and Environmental Engineering Reports 25, n^o 2 (1 juin 2017) : 125–36. http://dx.doi.org/10.1515/ceer-2017-0024.

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Abstract The paper deals with the method to identify internal stresses in two-dimensional steel members. Steel members were investigated in the delivery stage and after assembly, by means of electric-arc welding. In order to perform the member assessment two methods to identify the stress variation were applied. The first is a non-destructive measurement method employing local external magnetic field and to detecting the induced voltage, including Barkhausen noise The analysis of the latter allows to assess internal stresses in a surface layer of the material. The second method, essential in the paper, is a semi-trepanation Mathar method of tensometric strain variation measurement in the course of a controlled void-making in the material. Variation of internal stress distribution in the material led to the choice of welding technology to join. The assembly process altered the actual stresses and made up new stresses, triggering post-welding stresses as a response for the excessive stress variation.

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Zimmerman, J., T. Majewski et Z. Rymuza. « Modelling of the nanoindentation process of ultrathin films ». International Journal of Materials Research 96, n^o 11 (1 novembre 2005) : 1296–300. http://dx.doi.org/10.1515/ijmr-2005-0226.

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Abstract A model of the nanoindentation process was elaborated using the finite-element method. The ADINA software was used in the computation of the load – displacement curve. The distribution of stresses in the TiN film on a smooth substrate (Si) was found. The influence of mechanical material properties of the film and substrate on the process of indentation and the stress distribution was considered. The effect of yield stress, tip’s radius and hardening modulus was discussed. The results were compared with the results of experimental nanoindentation tests performed for ultrathin films.

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Tong, Xing, Yu-Chao Li, Han Ke, Ying Li et Qian Pan. « In situ stress states and lateral deformations of soil–bentonite cutoff walls during consolidation process ». Canadian Geotechnical Journal 57, n^o 1 (janvier 2020) : 139–48. http://dx.doi.org/10.1139/cgj-2018-0503.

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A long-term in situ test was performed on two soil–bentonite (SB) cutoff walls with different dimensions. The total stresses and pore pressures in the walls were monitored for 8 months, and the lateral wall deformations were monitored for 15 months. The monitoring results revealed that the primary consolidation of the presented SB cutoff walls took approximately 8 months. In the first 5 days, the stress states of the walls were nearly isotropic. The total stresses were less than the geostatic stress, and the lateral wall deformations were negligible. As the consolidation developed, the total horizontal stresses in the walls decreased and then remained unchanged at most depths after 1 month, while the stresses at the bottoms continued decreasing. The nonlinear profiles of the horizontal effective stresses in the cutoff walls were similar to the active earth pressure distributions behind the retaining walls moving in translation mode. The trench sidewall movements were found in translation mode within a specific depth range. Obvious dependencies of the horizontal effective stress and the horizontal strain on the wall height were observed. Comparison with the literature illustrates the influence of backfill properties on the consolidation behavior of the SB cutoff walls.

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Lu, Chang Liang, Fang You Hu, Xu Ren Huang, De Xian Yi, Ai Yong Cui et Bin Hu. « Analysis of Thermal Elasto-Plastic Stress during Pulsed Laser Heating a K418 Alloy Plate ». Advanced Materials Research 538-541 (juin 2012) : 1892–96. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.1892.

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The paper presents a study on analysis of thermal elasto-plastic stress during pulsed laser heating a K418 alloy plate. Based on elasto-plastic constitutive relationship, a spatial finite element model was established to simulate the whole process. The distribution and evolutions of temperature and stress field was calculated. The stresses induced during the process are highly heterogeneous because of the recurrent changing temperature field. The stresses during the process fluctuate as the temperature field changes. High level tensile residual stresses reside in the fusion zone after the laser process. Compared to all other stress components, longitudinal stress is the highest and will have considerable influences over the distortion level and failure of the material.

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Zhou, Li Qun, Yu Ping Li et Cai Ming Fu. « Drawing Process Analysis for Electrodeposited Nickel Coating by Finite Element Method ». Advanced Materials Research 291-294 (juillet 2011) : 606–9. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.606.

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A finite element method is used to simulate the deep drawing processes of nickel coating with steel substrate into battery shells. The Belytschko-Wong-Chiang shell elements are used and the kinematical work hardening model is adopted, while the ties with failure contact criterion is given to the coating and substrate interface. The stress-strain field and interfacial stresses in the drawing processes are obtained. The nickel coating appeared to be yielded in the drawing processes, of which the maximum effective stress reached 241MPa, and the biggest effective strain reached 0.7524. The interfacial stresses in the coating and substrate varied during the drawing process, and their maximal values reached 40MPa in compressive state.

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