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Cheng Jiang - One of the best experts on this subject based on the ideXlab platform.
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stress Strain Relationship of frp confined concrete columns under combined axial load and bending moment
Composites Part B-engineering, 2018Co-Authors: Yugui Cao, Cheng JiangAbstract:Abstract The stress-Strain Relationship of FRP confined concrete columns under eccentric loading is different from that under concentric loading. However, eccentric loading can have different load paths, e.g. constant axial force with increasing load eccentricity or constant load eccentricity with increasing axial load. The effect of different load paths on the stress-Strain behavior of eccentrically loaded columns has remained unclear to date. It was believed previously that such difference in load paths could be insignificant for the stress-Strain behavior of FRP confined concrete columns under eccentric loading. Unexpectedly, the study in this work on two different load paths demonstrates that the stress-Strain behavior can be very different. A new stress-Strain model for FRP confined circular concrete columns under constant axial force and increasing load eccentricity is developed in this work for engineering applications.
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effect of load eccentricity on the stress Strain Relationship of frp confined concrete columns
Composite Structures, 2013Co-Authors: Yufei Wu, Cheng JiangAbstract:Abstract Although fiber reinforced polymer (FRP) confined concrete columns have been extensively investigated, a satisfactory stress–Strain model for the columns under eccentric loading has not been developed because of the complications of the problem. The analytical study in this paper indicates that even the key factors that affect the stress–Strain Relationship have not been correctly identified so far. This paper presents an experimental and analytical study of FRP confined circular concrete columns under eccentric loading. Thirty-six short concrete cylinders were tested under varying levels of load eccentricity and FRP jacket stiffness. Based on analyses of the test results, a new model for the stress–Strain Relationship of FRP-confined columns under eccentric loading is developed. It is concluded from this work that the stress–Strain models previously developed for concentrically loaded columns are inadequate for predicting column response under eccentric loading. The stress–Strain curve shows a significant stiffening trend when load eccentricity increases.
Hans Gregersen - One of the best experts on this subject based on the ideXlab platform.
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Longitudinal residual Strain and stress-Strain Relationship in rat small intestine.
Biomedical engineering online, 2006Co-Authors: Yanling Dou, Jingbo Zhao, Yanhua Fan, Hans GregersenAbstract:Background To obtain a more detailed description of the stress-free state of the intestinal wall, longitudinal residual Strain measurements are needed. Furthermore, data on longitudinal stress-Strain relations in visceral organs are scarce. The present study aims to investigate the longitudinal residual Strain and the longitudinal stress-Strain Relationship in the rat small intestine.
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longitudinal residual Strain and stress Strain Relationship in rat small intestine
Biomedical Engineering Online, 2006Co-Authors: Jingbo Zhao, Yanling Dou, Hans Gregersen, Yanhua FanAbstract:To obtain a more detailed description of the stress-free state of the intestinal wall, longitudinal residual Strain measurements are needed. Furthermore, data on longitudinal stress-Strain relations in visceral organs are scarce. The present study aims to investigate the longitudinal residual Strain and the longitudinal stress-Strain Relationship in the rat small intestine. The longitudinal zero-stress state was obtained by cutting tissue strips parallel to the longitudinal axis of the intestine. The longitudinal residual stress was characterized by a bending angle (unit: degrees per unit length and positive when bending outwards). Residual Strain was computed from the change in dimensions between the zero-stress state and the no-load state. Longitudinal stresses and Strains were computed from stretch experiments in the distal ileum at luminal pressures ranging from 0–4 cmH2O. Large morphometric variations were found between the duodenum and ileum with the largest wall thickness and wall area in the duodenum and the largest inner circumference and luminal area in the distal ileum (p 0.5). The longitudinal residual Strain was tensile at the serosal surface and compressive at the mucosal surface. Hence, the neutral axis was approximately in the mid-wall. The longitudinal residual Strain and the bending angle was not uniform around the intestinal circumference and had the highest values on the mesenteric sides (p < 0.001). The stress-Strain curves fitted well to the mono-exponential function with determination coefficients above 0.96. The α constant increased with the pressure, indicating the intestinal wall became stiffer in longitudinal direction when pressurized. Large longitudinal residual Strains reside in the small intestine and showed circumferential variation. This indicates that the tissue is not uniform and cannot be treated as a homogenous material. The longitudinal stiffness of the intestinal wall increased with luminal pressure. Longitudinal residual Strains must be taken into account in studies of gastrointestinal biomechanical properties.
Jianzhuang Xiao - One of the best experts on this subject based on the ideXlab platform.
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variability of stress Strain Relationship for recycled aggregate concrete under uniaxial compression loading
Journal of Cleaner Production, 2018Co-Authors: Jianzhuang Xiao, Kaijian Zhang, Ali AkbarnezhadAbstract:Abstract Uniaxial compression loading tests were carried out to investigate the variability in stress-Strain Relationship of recycled aggregate concrete (RAC) due to intrinsic variability in properties of recycled coarse aggregates (RCAs). RCAs were selected from a single source to minimize the effects of potential variations in properties of waste concrete. Natural aggregate concrete (NAC) and RAC prisms were designed with different RCA replacement ratios but similar compressive strength. The results show that the RAC prisms have a similar failure pattern with that of NAC specimens. The RAC specimens were however found to have a lower elastic modulus and a higher peak Strain. The variability of the peak stress, peak Strain, elastic modulus and ultimate Strain was found to follow a normal distribution. Based on the collected experimental data, a modified RAC stress-Strain model was proposed. The RAC was found to possess a bit more brittle properties than NAC, as indicated by the steeper stress-Strain curve's descending branch for the RAC. The variability of RAC stress-Strain model was evaluated and the corresponding probability density function (PDF) and cumulative distribution function (CDF) were discussed.
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effects of interfacial transition zones on the stress Strain behavior of modeled recycled aggregate concrete
Cement and Concrete Research, 2013Co-Authors: Jianzhuang Xiao, Wengui Li, David J Corr, Surendra P ShahAbstract:Abstract Based on nanoindentation tests and analysis, the constitutive Relationship of the Interfacial Transition Zones (ITZs) in Recycled Aggregate Concrete (RAC) is put forward. Together with the meso/micro-scale mechanical properties of each phase in Modeled Recycled Aggregate Concrete (MRAC), the plastic-damage constitutive models are employed in numerical studies on MRAC under uniaxial compression and uniaxial tension loadings to predict the overall mechanical behavior, particularly the stress–Strain Relationship. After the calibration and validation with the experimental results, a parametric study has been undertaken to analyze the effects of ITZs and new mortar matrix on the stress–Strain Relationship of MRAC. It is revealed that the mechanical properties of new mortar matrix and relative mechanical properties between ITZs and mortar matrices play a significant role in the overall stress–Strain Relationship and failure patterns of MRAC under both uniaxial compression and uniaxial tension loadings.
I E Shkolnik - One of the best experts on this subject based on the ideXlab platform.
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influence of high Strain rates on stress Strain Relationship strength and elastic modulus of concrete
Cement & Concrete Composites, 2008Co-Authors: I E ShkolnikAbstract:Abstract Earlier papers showed a method for strength evaluation at high Strain rate from the results of static tests, and a method for evaluating modulus of elasticity at static loading from tests based on stress-wave propagation. This paper presents new results on the influence of high Strain rates on the stress–Strain Relationship, strength and modulus of elasticity using the thermofluctuation theory, principle of accumulation and development damages as well as nonlinear behavior of concrete under loading. Obtained equations explain and unify the influence of high rates on the mechanical properties of concrete for different kinds of uniaxial stress. Comparative study showed again substantial agreement with existing experimental results and general equations by the Comite Euro-International du Beton (CEB) Model Code. The developed approach diminishes the labor expenses for tests of concrete under high rates of loading.
Yugui Cao - One of the best experts on this subject based on the ideXlab platform.
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stress Strain Relationship of frp confined concrete columns under combined axial load and bending moment
Composites Part B-engineering, 2018Co-Authors: Yugui Cao, Cheng JiangAbstract:Abstract The stress-Strain Relationship of FRP confined concrete columns under eccentric loading is different from that under concentric loading. However, eccentric loading can have different load paths, e.g. constant axial force with increasing load eccentricity or constant load eccentricity with increasing axial load. The effect of different load paths on the stress-Strain behavior of eccentrically loaded columns has remained unclear to date. It was believed previously that such difference in load paths could be insignificant for the stress-Strain behavior of FRP confined concrete columns under eccentric loading. Unexpectedly, the study in this work on two different load paths demonstrates that the stress-Strain behavior can be very different. A new stress-Strain model for FRP confined circular concrete columns under constant axial force and increasing load eccentricity is developed in this work for engineering applications.
