Stress Distributions During Fiber Pull-Out

1996 ◽  
Vol 63 (2) ◽  
pp. 301-306 ◽  
Author(s):  
R. Krishna Kumar ◽  
J. N. Reddy
Keyword(s):  
Stress Distribution ◽  
Axial Stress ◽  
Friction Stress ◽  
Stress Distributions ◽  
Pull Out ◽  
Reinforced Composite ◽  
First Case ◽  
The Matrix ◽  
Axial Stress Distribution ◽  
Perturbed Lagrangian

Fiber pull-out resistance is an important mechanism of energy absorption during the failure of fiber-reinforced composite materials. This paper deals with axial stress distribution in the fiber during a pull-out. The frictional constraint between the fiber and the matrix is modeled with a perturbed Lagrangian approach and Coulomb’s law of friction. Stress distribution has been determined for three cases, using the finite element method. The first case deals with the pull out of a fully embedded fiber. The second determines the stress distribution during fiber pull-out in the presence of a broken-embedded fiber. The third model attempts to solve the pull out of a coated fiber. The results for the first case compares favorably with those in existing literature. A local “pinching” effect, due to the matrix collapse behind the pulled fiber, is brought out clearly by this model. The second study indicates that the “plug” effect may not be significant in affecting the stress distribution. Lastly, the effects of coating stiffness and thickness are investigated.

Stress Distribution of the Composites Reinforced by Slub-Like Short Fibers

2007 ◽  
Vol 353-358 ◽  
pp. 389-391 ◽  
Author(s):  
Li Xin Dong ◽  
Guang Ze Dai ◽  
Xian Feng Zhou ◽  
L.L. Liu ◽  
Qing Qing Ni
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Textile Industry ◽  
Axial Stress ◽  
Interfacial Shear Stress ◽  
Interfacial Shear ◽  
Reinforced Composites ◽  
Stress Distributions ◽  
Short Fibers ◽  
The Matrix

The model of slub-like short fibers reinforced composites is suggested from the viewpoint of bamboo in the nature and patterns characteristic of simulated silk PET used in textile industry. The stress distributions in the enlarged-end fiber and in the matrix are analyzed. The axial stress in the fiber and matrix is found to increase and the interfacial shear stress decrease with the radius of the enlarged end.

scholarly journals Experimental Investigation of Steel Plate Shear Walls under Shear-Compression Interaction

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Yang Lv ◽  
Ling Li ◽  
Di Wu ◽  
Bo Zhong ◽  
Yu Chen ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Steel Plate ◽  
Axial Stress ◽  
Shear Walls ◽  
Shear Capacity ◽  
Steel Plate Shear Walls ◽  
Steel Plate Shear Wall ◽  
Gravity Load ◽  
Moment Resisting ◽  
Axial Stress Distribution

Four scaled one-storey single-bay steel plate shear wall (SPSW) specimens with unstiffened panels were tested to determine their behaviour under cyclic loadings. The shear walls had moment-resisting beam-to-column connections. Four different vertical loads, i.e., 300 kN, 600 kN, 900 kN, and 1200 kN, representing the gravity load of the upper storeys were applied at the top of the boundary columns through a force distribution beam. A horizontal cyclic load was then applied at the top of the specimens. The specimen behaviour, envelope curves, axial stress distribution of the infill steel plate, and shear capacity were analyzed. The axial stress distribution and envelope curves were compared with the values predicted using an analytical model available in the literature.

Study on the Interfacial Shear Stress Distribution Characteristics of Geotechnical Prestressed Anchorage Structure

2014 ◽  
Vol 919-921 ◽  
pp. 773-776
Author(s):  
Si Feng Zhang ◽  
Long Zhang ◽  
Lin Li ◽  
Xiu Guang Song
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Model Test ◽  
Axial Stress ◽  
Interfacial Shear Stress ◽  
Tensile Load ◽  
Interfacial Shear ◽  
Shear Stress Distribution ◽  
Distribution Characteristics ◽  
Axial Stress Distribution

The ultimate bearing capacity of prestressed anchorage structure is directly related to the interfacial shear stress distribution characteristics of the inner anchorage section. Firstly, the axial stress distribution characteristics of the inner anchorage section for the geotechnical prestressed anchorage structure under tensile load are further studied by indoor similarity model test, and the corresponding fitting formula is established. Based on this result and the force equilibrium conditions of rod body’s micro-segment, the rod body interfacial shear stress distribution characteristics formula is also derived, which fits well with the results of the indoor model test. The research achievements have important significance for the further study on stress distribution characteristics of the inner anchorage section.

scholarly journals A Review of the Pull-Out Mechanism in the Fracture of Brittle-Matrix Fibre-Reinforced Composites

2007 ◽  
Vol 16 (1) ◽  
pp. 096369350701600 ◽  
Author(s):  
Konstantinos G. Dassios
Keyword(s):  
Fibre Strength ◽  
Brittle Matrix ◽  
Pull Out ◽  
Mechanics Of Materials ◽  
Reinforced Composite ◽  
Surface Flaws ◽  
The Matrix ◽  
Energy Dissipation Capacity ◽  
Fibre Reinforced Composites

The current work addresses the role of damage mechanisms such as interfacial debonding, crack deflection, bridging and sliding during fracture of a brittle-matrix fibre-reinforced composite with respect to their energy dissipation capacity and their impact on the pull-out mechanism. The aim of the paper is to explain why fibre failure is preferably concentrated within the matrix environment to give rise to the pull-out mechanism and not within the crack flanks where fibre stress is maximum. Two approaches, mechanics of materials and fracture mechanics, are invoked to demonstrate that pull-out is triggered and dominated primarily by the fibres’ surface flaw distribution rather than by fibre strength. The origins of pull-out are also explained in terms of statistics and the identified failure pattern of fibres in composites is discussed in view of its implications to experimental practice. The implications of the findings are summarized in a current need for a deeper investigation into the micromechanics of reinforcement in composites, the role of surface flaws and the interface as well as in the competing roles of strength and flaw size.

Interfacial phenomena in the fracture resistance of interfaces

1988 ◽  
Vol 46 ◽  
pp. 720-721
Author(s):  
A. G. Evans
Keyword(s):  
Fracture Resistance ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Friction Stress ◽  
Matrix Composites ◽  
Low Friction ◽  
Fiber Failure ◽  
Pull Out ◽  
Brittle Matrix Composites ◽  
The Matrix

In composite systems, the mechanical response of interfaces to the approach of cracks that initially form either in the matrix or in the fiber dominates the mechanical performance. In particular, in brittle matrix composites, the interface must have a sufficiently low fracture resistance compared with that of both the fiber and matrix that the crack diverts into the interface and debonds the fiber, Thereafter, the debonded fiber must be able to slide against the matrix with a low friction stress in order to inhibit fiber failure and thus enhance pull-out. These processes are schematically illustrated in Fig. 1. Mechanics investigations have established requirements concerning debonding and sliding that must be satisfied in order to achieve good composite properties. At the simplest level, these studies reveal that the fracture energy of the interface should be less than about one-third that of either the fiber or the matrix.

Numerical Simulation of In-Service Welding of a Pressurized Pipeline

2006 ◽  
Vol 129 (1) ◽  
pp. 66-72 ◽  
Author(s):  
XiaoLong Xue ◽  
ZhiFu Sang ◽  
JiaGui Zhu ◽  
G. E. O. Widera
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Temperature Field ◽  
Stress Distribution ◽  
Axial Stress ◽  
The Finite Element Method ◽  
Heat Effects ◽  
Inner Surface ◽  
Axial Stress Distribution ◽  
Flow Case

The temperature field and stress distribution for in-service welding of a flowing media, pressurized pipeline are simulated by use of the finite element method (FEM). In order to investigate the effect of flowing media on the temperature field of in-service welding, the results are compared with those of a no-flow case. It is found that the flowing media took away most of the heat effects from welding. The cooling is accelerated and the peak temperature of the inner surface of the pipe is much lower than that of the no-flow case. An experiment was performed to verify the accuracy of the numerical model. The presence of internal pressure, i.e., flowing media, in the pipeline significantly affects the postcooling axial stress distribution.

scholarly journals Bearing Characteristics of Surrounding Rock of Deep Mining Roadway with Full and End Bolt Anchorages: A Comparative Numerical and Experimental Study

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Wenbao Shi ◽  
Yan Li ◽  
Wanfeng Li ◽  
Shihui Li
Keyword(s):  
Stress Distribution ◽  
Axial Force ◽  
Axial Stress ◽  
Field Tests ◽  
Surrounding Rock ◽  
Deep Mining ◽  
Pull Out ◽  
Laboratory Test Results ◽  
Full Anchorage ◽  
Bolt Support

The support strength of surrounding rock in deep mining roadways can be significantly improved by replacing the end bolt anchorage with a full one. The support effects of both types of anchorage and the axial stress distribution characteristics in anchored bolt bodies were assessed via the indoor pull-out test, simulated via the FLAC3D software, and verified by field measurements. The stability and variation patterns of the axial force, as well as the evolution law of bearing characteristics of surrounding rock, were analyzed. The results indicate that the polymorphic deformations of deep mining roadway surrounding rock and the bolt support body interact synchronously. The axial force evolution trend in bolt bodies with end anchorage revealed by field tests was consistent with the laboratory test results, in contrast to that of full anchorage. Although stress distribution laws in both sides of the mining roadway were the same for both types of anchorage, the vertical stress peak and damage range of full-anchored surrounding rock slightly exceeded those of the end-anchored one. The anchored area bearing a higher load alleviated the stress concentration of the surrounding rock. Since the deformations in fully and end anchored surrounding rocks increased gradually and sharply, respectively, the full anchorage is more conducive to deformation moving control of deep mining roadway surrounding rock. The research results can provide theoretical guidance for the design and construction of deep mining roadway bolt support.

scholarly journals Pullout Test on Fully Grouted Bolt Sheathed by Different Length of Segmented Steel Tubes

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Xiaowei Feng ◽  
Nong Zhang ◽  
Guichen Li ◽  
Gangye Guo
Keyword(s):  
Stress Distribution ◽  
High Performance ◽  
Mechanical Performance ◽  
Axial Stress ◽  
Testing Machine ◽  
Steel Tube ◽  
Steel Tubes ◽  
Specific Order ◽  
Axial Stress Distribution ◽  
Fully Grouted Bolt

In order to evaluate the anchorage performance of rebar bolt sheathed by different length of segmented steel tubes, a total of eight groups of pullout tests were conducted in this study. The steel tubes, segmented by 5 cm, 7 cm, 9 cm, 10 cm, and 15 cm, utilized in current study were bonded together by a high performance two-component adhesive to form standard 30 cm long steel tube. Unlike axial stress distribution in bolt, the axial stress distribution in steel tube showed exponential decrease trend from tube-clamp end to bolt-clamp end; thus a series of interesting results were observed. For instance, the sequence for segments detachment had its specific order of priority; the failure form of bolting system, the load oscillation characteristics, and the final displacement were highly determined by the length of the last segment, namely, the one fixed by clamp of testing machine. Moreover, the load-displacement relationship for some particular samples was further investigated from the perspective of energy transformation, and the disequilibrium extension of interfacial decoupling was also discussed. This paper, from a relatively idealized perspective, presents a laboratorial solution to interpret the mechanical performance of the bolt installed in layered strata; so far at least it demonstrates that a bolt installed in comparatively thicker layer of strata can last more durable and stable.

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