scholarly journals Investigation of Bursting Stress and Spalling Stress in Post-tensioned Anchorage Zones

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Linyun Zhou
Keyword(s):  
Symmetry Axis ◽  
Normal Stresses ◽  
Transverse Stress ◽  
Stream Tube ◽  
Bearing Plate ◽  
The Past ◽  
Cracking Control ◽  
Transverse Stresses ◽  
Plate Width ◽  
Post Tensioned

AbstractOver the past decades, considerable efforts have been made to quantify the bursting forces in the post-tensioned anchorage zones based on the simplified model or fitting formulas, however reproducing the transverse stress distribution is still a challenging topic, which is also important to detail the reinforcing details in the anchorage zones, especially for cracking control. To address this issue, this paper is devoted to seeking an elasticity solution for transverse stresses in the anchorage zones, and providing a more rational equation for transverse distribution in anchorage zones. The sum function of normal stresses is employed to solve the stresses filed in the anchorage zones with concentric load and two eccentric loads. The bursting stresses in the concentric anchorage zones and spalling stresses in the eccentric anchorage zones are verified by the photoelastic tests. The transverse stresses along the symmetry axis of the eccentric anchorage zones can be handled as a concentric single anchorage zone with equivalent bearing plate width. Moreover, according to the concept of force stream tube, the profiles of isostatic line of compression (ILCs) are determined and validated, which confirms the existence of ILCs.

scholarly journals RESULTS OF EXPERIMENTAL RESEARCH OF THE REINFORCED CONCRETE SHELL-SLAB

2019 ◽  
Vol 16 (3) ◽  
pp. 378-392
Author(s):  
A. V. Selivano ◽  
F. F. Reger
Keyword(s):  
Reinforced Concrete ◽  
Experimental Research ◽  
Practical Significance ◽  
Transverse Stress ◽  
Program Complex ◽  
State Evaluation ◽  
Concrete Shell ◽  
Ultimate Equilibrium ◽  
Transverse Stresses ◽  
Theoretical Stress

Introducton. The paper demonstrates the results of experimental research of the reinforced concrete shell-slab under the action of vertical uniformly distributed load. The authors also present the comparison of such research results with the results of stress-strain state evaluation performed in the “Lira” software package.Materials and methods. The authors tested the reinforced concrete model representing physically similar copy with the 1:5 scale coefficients by general size, and by separate details. The load was applied in 10–15% doze of the theoretical bearing capacity of the plate.Results. The authors calculated the experimental transverse stress σх,3,exp, which was in full-scale construction and in the 3 central sphere. The authors also made the comparison of such transverse stress with theoretical transverse stresses σх,3,teor and the comparison was performed in the “Lira” program complex. The diagrams of the above stresses were well matched by outlines and values.Discussion and conclusions. As a result, the experimental (σx, 3,exp.) and theoretical (σx,3,theor.) stresses are compressive near the shell-slab center. Its maximum stress values (σx, 3, exp) reach x/b=0,5 at a point with a relative coordinate, and the stress (σx,3,theor.) – x/b ≈ 0,45.The zero voltage values σx,3,exp. reach a quarter of the shelf width, theoretical stress –with x/b ≈ 0,3 mm ratio.Maximum values of experimental and theoretical tensile stresses σx, 3 reach x/b ≈ 0,15 ratio. Therefore, the values are close to each other, and do not exceed the standard concrete tensile resistance Rbt, ser.The practical significance of the study is to obtain experimental evidence of the abandoning possibility of the horizontal transverse reinforcement of the shelf, which would reduce the complexity and cost of the investigated structures production.The prospects conclude in:research of the shell-slab operation at the stage of ultimate equilibrium;research of the shell-slab crack resistance and stiffness at all stages of its operation;research of the shell-slab operation taking into account the fixation in the transverse direction of its longitudinal contour edges along entire length.

scholarly journals Experimental Investigation on Web Crippling Property of High-Strength Cold-Formed (HSCF) Rectangular Steel Tube

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Xianglong Liu ◽  
Jicheng Zhang ◽  
Yuanqi Li ◽  
Lei Zeng ◽  
Guofeng Du
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
High Strength ◽  
Ultimate Bearing Capacity ◽  
Height Ratio ◽  
Steel Tubes ◽  
Web Crippling ◽  
Bearing Plate ◽  
Bearing Load ◽  
Plate Width

To research the web crippling performance (i.e., the ultimate web crippling bearing capacity and ductility) of high-strength cold-formed (HSCF) rectangular steel tubes under concentrated load, thirty-six specimens with different bearing plate width, width-to-height ratio, boundaries, and loading conditions are fabricated and tested in this paper. Particularly, four kinds of boundaries and loading conditions are utilized, including end-two-flange (ETF), end-one-flange (EOF), interior-two-flange (ITF), and interior-one-flange (IOF). Research revealed the failure modes of HSCF rectangular steel tubes under concentrated loads applied at the end or interior. Moreover, the load-displacement curves and load-strain curves are obtained. The results show that the ultimate crippling capacity of webs increases significantly with larger bearing plate width and width-to-height ratio. Specimens subjected to interior bearing load have higher ultimate strength and deformation capacity than counterparts that are subjected to bearing load at the end. Additionally, in the middle of the compression web, all strain measuring points enter the plasticity stage and finally appear in the plastic hinge area. Subsequently, the failure modes and ultimate bearing capacity are simulated by the finite element method (FEM), which is implemented via ABAQUS. By comparing the test results with the numerical values, demonstrate the effectiveness of the proposed numerical simulation on investigating the failure modes and the ultimate bearing capacity of HSCF rectangular steel tubes. Finally, regarding the conservative and dangerous calculation of web crippling ultimate bearing capacity in current codes, we can provide a good guidance for future work, particularly the proposed calculation equations for ultimate bearing capacity of HSCF rectangular steel tubes.

scholarly journals Recent Developments in the Young Planetary Nebula HEN-1357

1998 ◽  
Vol 11 (1) ◽  
pp. 359-359
Author(s):  
M. Bobrowsky
Keyword(s):  
Planetary Nebula ◽  
Symmetry Axis ◽  
Major Axis ◽  
Central Star ◽  
Circular Ring ◽  
Line Of Sight ◽  
Complex Object ◽  
The Past ◽  
Recent Developments ◽  
Two Bubbles

Observations over the past four decades have revealed significant changes in the spectrum of Hen-1357. Here we present HST images and spectra showing the most recent developments. In 1950, Henize saw only Hα in emission; but more recent observations by Parthasarathy et al. in 1992 showed strong forbidden lines consistent with a young planetary nebula. The spherically aberrated 1992 HST images, in which Bobrowsky first optically resolved the nebula, showed a compact nebula surrounding the central star. Nebular gas appeared most strongly concentrated in an ellipse with its major axis subtending 1".6 from NW to SE. If this ellipse is actually a circular ring viewed obliquely, then our line of sight is inclined from the symmetry axis by 5°. Above and below the ring of gas are two bubbles containing lower-density gas. At the tip of each bubble, there is a hole where the gas inside the bubbles has broken through and is now escaping. The windblown appearance is consistent with the blueshifted Si IV (1394-1403Å) and Al III (1855-1863Å) doublets observed by Parthasarathy et al. that indicated the presence of a strong stellar wind. The N V (1239-1243Å) to C IV (1548-1551Å) ratio has increased in recent years, consistent with a young nebula becoming increasingly ionized. Our recent (1996) spectra reveal additional developments that show the realtime development of this young nebula. Finally, the new HST Planetary Camera images of the nebula show detailed structure indicating a much more complex object than previously known, including the presence of a companion star 0".3 from the central star.

scholarly journals Local buckling of cantilever wall of thin-walled member with longitudinal and transverse stress variation

2015 ◽  
Vol 14 (2) ◽  
pp. 113-121 ◽  
Author(s):  
Andrzej Szychowski
Keyword(s):  
Local Buckling ◽  
Transverse Stress ◽  
Linear Distribution ◽  
Stress Variation ◽  
Plate Buckling ◽  
Thin Walled ◽  
The Stability ◽  
Elastically Restrained ◽  
Distribution Of Stresses ◽  
Plate Width

The paper presents results of the investigation into the stability of elastically restrained cantilever walls (plates) with longitudinal and transverse stress variation. A linear distribution of stresses in the direction of the wall (plate) width and the linear or nonlinear (in accordance with parabola 20) distribution of stresses along the wall length were assumed. Plots of plate buckling coefficients (k) for variously supported and variously loaded cantilever plates, which are not found in the literature, were determined.

scholarly journals Symmetry-Aware 6D Object Pose Estimation via Multitask Learning

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Hongjia Zhang ◽  
Junwen Huang ◽  
Xin Xu ◽  
Qiang Fang ◽  
Yifei Shi
Keyword(s):  
Pose Estimation ◽  
Symmetry Axis ◽  
Multitask Learning ◽  
The Past ◽  
Learning Scheme ◽  
Key Points ◽  
Optimization Function ◽  
Object Pose Estimation

Although 6D object pose estimation has been intensively explored in the past decades, the performance is still not fully satisfactory, especially when it comes to symmetric objects. In this paper, we study the problem of 6D object pose estimation by leveraging the information of object symmetry. To this end, a network is proposed that predicts 6D object pose and object reflectional symmetry as well as the key points simultaneously via a multitask learning scheme. Consequently, the pose estimation is aware of and regulated by the symmetry axis and the key points of the to-be-estimated objects. Moreover, we devise an optimization function to refine the predicted 6D object pose by considering the predicted symmetry. Experiments on two datasets demonstrate that the proposed symmetry-aware approach outperforms the existing methods in terms of predicting 6D pose estimation of symmetric objects.

Faserschonende Carbonfaserproduktion durch innovatives Galetten-Oberflächen-Design - CarboGerd

2021 ◽  
Vol 68 (3-4) ◽  
Author(s):  
Lukas Lechthaler ◽  
Felix Pohlkemper ◽  
Marie-Isabell Glaubke ◽  
Kees Egbers ◽  
Thomas Gries ◽  
...  
Keyword(s):  
Carbon Fibre ◽  
Anisotropic Material ◽  
Static Friction ◽  
Fibre Production ◽  
Prototype System ◽  
Carbon Fibres ◽  
Transverse Stress ◽  
Material Behaviour ◽  
Fibre Direction ◽  
Transverse Stresses

While carbon fibres can easily absorb forces in the fibre direction, they are extremely sensitive to transverse stress due to their anisotropic material behaviour. During the manufacturing process, unavoidable transverse stresses are induced in the fibre by the drive and deflection godets, which can damage or destroy individual filaments of the roving. The demand for a surface that is gentle on the fibre is offset by the static friction required between the fibre and the godet in order to drive the fibre. The aim of the CarboGerd research project is therefore to develop and validate an optimal godet coating for fibre-protecting and quality-assuring carbon fibre production. For this purpose, both typical coatings (ceramic, Topocrom coatings) and unconventional solutions (elastomer, PACVD coatings) are being tribologically investigated on a laboratory scale and validated on a prototype system.

scholarly journals Previous Research Works on Reinforced Concrete Curved Beams

2021 ◽  
Vol 318 ◽  
pp. 03011
Author(s):  
W. H. Khaleel ◽  
A. A. Talal ◽  
N. H. Baidaa ◽  
K. S. Abdul-Razzaq ◽  
A. A. Dawood
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Shear Failure ◽  
Research Work ◽  
Three Dimensional ◽  
Beam Width ◽  
Curved Beams ◽  
Analysis And Design ◽  
Bearing Plate ◽  
Plate Width

The current research work summarizes some previous research works on horizontally curved beams. Because of curvature, torsional effects in the analysis and design should be included. Diameter of ring beam, number of supports, beam width, compressive strength of the concrete, and bearing plate width. Which can be summarized from previous studies is that increasing diameter of ring by about 25-75% decreases the capacity load by about 14-36%, while increasing number of supports by about 33-100%, beam width by about 25-75%, compressive strength of concrete by about 24-76%, and bearing plate width by about 25-75% increases the capacity load by about 62-189%, 25-75%, 24-76%, and 5-16%, respectively due to the beam section increase and/or its properties. Frequently, reinforced concrete deep ring beams exhibit shear failure in a manner similar to straight beams. Strut and tie model (STM) and plastic analysis are useful tools for efficiently analyzing ring or curved deep beams. In addition, the nonlinear three-dimensional finite element modeling is typical for predicting the deep curved beams strength and behavior.

scholarly journals Calculation of lateral stresses for uniaxial compression of geomaterial samples

2021 ◽  
Vol 929 (1) ◽  
pp. 012015
Author(s):  
A A Kirilov ◽  
V N Sychev
Keyword(s):  
Mechanical Stress ◽  
Uniaxial Compression ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Transverse Stress ◽  
Measured Load ◽  
The Difference ◽  
Transverse Stresses ◽  
Analytical Expressions

Abstract A method is proposed for calculating the transverce stresses during uniaxial compression of geomaterial samples from the measured load and mutually perpendicular deformations. Analytical expressions connecting the indicated parameters are obtained. The dependences of the change in the calculated transverse stresses on time are plotted for various values of Poisson’s ratio. The difference in transverse stresses demonstrates a much greater sensitivity to mechanical stress than each transverse stress separately. Sharp changes in the values of the difference in transverse stresses are observed, which coincide with bursts of AE activity.

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