scholarly journals Investigation on the behavior of rigid polyvinylchloride pipes subjected to uniaxial compression loads

2017 ◽  
Vol 23 (3) ◽  
pp. 145
Author(s):  
Abdullah Ali Nasser Alhamati ◽  
Abdul Halim Ghazali ◽  
Jamalodin Norzaie
Keyword(s):  
Uniaxial Compression ◽  
Small Diameter ◽  
Experimental Tests ◽  
Displacement Curve ◽  
Axial Loads ◽  
Pipe System ◽  
Euler Buckling ◽  
Specimen Height ◽  
Brick Element ◽  
Load Displacement

The objective of this research was to investigate the capability of rigid Polyvinylchloride (PVC-U) pipes to sustain axial loads. The behavior of PVC-U pipes specimens subjected to short-term uniaxial compression loads were experimentally investigated. Results of the load-displacement tests on pipes of different wall thickness, diameter, and specimen heights were recorded. The experimental test results show that the PVC-U pipes are capable of supporting loads greater than the required design load (3.4 kN). Increasing the pipe specimen height decreases the pipe strength for supporting the axial loads.  Euler buckling was observed in the pipe specimens with small diameter and long axial height. Furthermore, an attempt has been made to utilize the ANSYS finite element commercial package to model the pipe system using eight noded brick element and the results were compared with those obtained from the experimental tests. Good agreement was found between the two sets of results, within the elastic range of the load-displacement curve.

scholarly journals Analysis of Bearing Strength of Post-Tensioning Anchorage Zone with Respect to Relative Bearing Area and Lateral Confinement Design

2021 ◽  
Vol 11 (18) ◽  
pp. 8386
Author(s):  
Jin-Kook Kim ◽  
Jun-Mo Yang
Keyword(s):  
Error Rate ◽  
Small Diameter ◽  
Average Error ◽  
Displacement Curve ◽  
Proportional Limit ◽  
Lateral Confinement ◽  
Bearing Strength ◽  
Bearing Plate ◽  
Load Displacement ◽  
Post Tensioning

This study aimed to evaluate the bearing strength of the post-tensioning anchorage zone with respect to the relative bearing area and lateral confinement design of spiral and stirrup rebars. Eleven specimens were fabricated and tested to fracture in accordance with EAD 160004-00-0301. Load-displacement curves and fracture modes were analyzed. Then, the conventional design equation for the bearing strength and previous findings on the relative bearing area was re-investigated in comparison with the test results. From the test, the representative findings are as follows: (1) A specimen with relatively small size and less lateral reinforcement is more likely to be affected by the wedge action of the anchorage device; however, a larger specimen is affected by both concrete crushing and/or spalling; (2) The behavior of the anchorage zone is markedly affected by the local behavior near the anchorage bearing plate, and the sectional efficiency is mostly determined by A/Ag; (3) For specimens with A/Ag = 9.52, the proportional limit of the load-displacement curve is determined by the yield of spiral rebar or fracture of the bearing plate, but the later part of the curve is determined by lateral confinement; (4) The maximum A/Ag that could produce 100% sectional efficiency is about 2.0 for the anchorage bearing plate used in the test; (5) For a fully confined specimen with a small-diameter spiral for minimum anchorage spacing, the stirrup rebar design mainly influences crack occurrence and patterns when the size of the specimen is equal to the minimum anchorage spacing; however, the area of the load-displacement curve after the proportional limit as well as crack occurrence and patterns are also influenced by stirrup rebar design when A/Ag is relatively large; (6) Finally, a revised design model is proposed to effectively estimate the ultimate bearing strength of the post-tensioning anchorage zone without respect to A/Ag. From the comparison of the design equations, it was concluded that the proposed equation provides a more reliable prediction with a 14.0% average error rate and 5.7% standard deviation of error rate.

scholarly journals Analysis of Concrete Failure on the Descending Branch of the Load-Displacement Curve

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 921
Author(s):  
Gennadiy Kolesnikov
Keyword(s):  
Uniaxial Compression ◽  
Modulus Of Elasticity ◽  
Stress And Strain ◽  
Displacement Curve ◽  
Compression Tests ◽  
Three Point Bending ◽  
Effective Stresses ◽  
Concrete Failure ◽  
Load Displacement ◽  
Displacement Diagram

In this paper, load-displacement and stress-strain diagrams are considered for the uniaxial compression of concrete and under three-point bending. It is known that the destruction of such materials occurs on the descending branch of the load-displacement diagram. The attention of the presented research is focused on the explanation of this phenomenon. Fracture mechanics approaches are used as a research tool. The method for determining effective stresses and modulus of elasticity of concrete based on the results of uniaxial compression tests has been substantiated. The ratios necessary for the calculation were obtained without any assumptions about the reinforcement of concrete and the mechanical properties of its components. However, the effect of these properties is considered indirectly, using the stress and strain peaks determined by standard concrete compression tests. It was found that the effective stresses increase both on the ascending branch and on the descending branch of the load-displacement diagram. This explains the destruction of concrete on the descending branch of the load-displacement diagram. The results of determining the stresses and modulus of elasticity under uniaxial compression are comparable with the results obtained in experiments known in the literature.

scholarly journals Study on the Strength Performance of Recycled Aggregate Concrete with Different Ages under Direct Shearing

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2312
Author(s):  
Xin Liang ◽  
Fang Yan ◽  
Yuliang Chen ◽  
Huiqin Wu ◽  
Peihuan Ye ◽  
...  
Keyword(s):  
Shear Strength ◽  
Shear Force ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Displacement Curve ◽  
Direct Shear ◽  
Replacement Ratio ◽  
Aggregate Concrete ◽  
Concrete Failure ◽  
Load Displacement

In order to study the mechanical properties of recycled aggregate concrete (RAC) at different ages, 264 standard cubes were designed to test its direct shear strength and cube compressive strength while considering the parameters of age and recycled aggregate replacement ratio. The failure pattern and load–displacement curve of specimens at direct shearing were obtained; the direct shear strength and residual shear strength were extracted from the load–displacement curves. Experimental results indicate that the influence of the replacement ratio for the front and side cracks of RAC is insignificant, with the former being straight and the latter relatively convoluted. At the age of three days, the damaged interface between aggregate and mortar is almost completely responsible for concrete failure; in addition to the damage of coarse aggregates, aggregate failure is also an important factor in concrete failure at other ages. The load–displacement curve of RAC at direct shearing can be divided into elasticity, elastoplasticity, plasticity, and stabilization stages. The brittleness of concrete decreases with its age, which is reflected in the gradual shortening of the elastoplastic stage. At 28 days of age, the peak direct shear force increases with the replacement ratio, while the trend is opposite at ages of 3 days, 7 days, and 14 days, respectively. The residual strength of RAC decreases inversely to the replacement ratio, with the rate of decline growing over time. A two-parameter RAC direct shear strength calculation formula was established based on the analysis of age and replacement rate to peak shear force of RAC. The relationship between cube compressive strength and direct shear strength of recycled concrete at various ages was investigated.

A novel method to determine critical CTOA directly by load-displacement curve

2020 ◽  
Vol 230 ◽  
pp. 107013
Author(s):  
Ying Zhen ◽  
Xuyang Li ◽  
Yuguang Cao ◽  
Shihua Zhang
Keyword(s):  
Displacement Curve ◽  
Novel Method ◽  
Load Displacement

Research on the Relationship between Indenter Tip Radius and Hardness with a Self-Designed Nanohardness Test Device

2008 ◽  
Vol 392-394 ◽  
pp. 267-270
Author(s):  
Qiang Liu ◽  
Ying Xue Yao ◽  
L. Zhou
Keyword(s):  
Single Crystal ◽  
Indentation Depth ◽  
Single Crystal Silicon ◽  
Indentation Hardness ◽  
Displacement Curve ◽  
Test Device ◽  
Crystal Silicon ◽  
Load Displacement ◽  
Depth Sensitivity ◽  
Tip Radius

Nanoindentation device has the ability to make the load-displacement measurement with sub-nanometer indentation depth sensitivity, and the nanohardness of the material can be achieved by the load-displacement curve. Aiming at the influence law of indenter tip radius to indentation hardness, testing on the hardness of single-crystal silicon were carried out with the new self-designed nanohardness test device based on nanoindentation technique. Two kinds of Berkovich indenter with radius 40nm and 60nm separately were used in this experiment. According to the load-depth curve, the hardness of single-crystal silicon was achieved by Oliver-Pharr method. Experimental results are presented which show that indenter tip radius do influence the hardness, the hardness value increases and the indentation size effect (ISE) becomes obvious with the increasing of tip radius under same indentation depth.

scholarly journals Evaluation Method of Granite Multiscale Mechanical Properties Based on Nanoindentation Technology

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Man Lei ◽  
Fa-ning Dang ◽  
Haibin Xue ◽  
Mingming He
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Uniaxial Compression ◽  
Compression Test ◽  
Evaluation Method ◽  
Poisson Ratio ◽  
Nanoindentation Test ◽  
Uniaxial Compression Test ◽  
Displacement Curve ◽  
Mineral Contents

In order to study the mechanical properties of granite at the micro- and nanoscale, the load-displacement curve, residual indentation information, and component information of the quartz, feldspar, and mica in granite were obtained using a nanoindentation test, a scanning electron microscope (SEM), and X-ray diffraction (XRD). The elastic modulus and the hardness of each component of the granite were obtained through statistical analysis. Treating rock as a composite material, the relation between the macro- and microscopic mechanical properties of rock was established through the theory of micromechanical homogenization. The transition from micromechanical parameters to macromechanical parameters was realized. The equivalent elastic modulus and Poisson’s ratio of the granite were obtained by the Self-consistent method, the Dilute method, and the Mori-Tanaka method. Compared with the elastic modulus and the Poisson ratio of granites measured by a uniaxial compression test and the available data, the applicability of the three methods were analyzed. The results show that the elastic modulus and hardness of the quartz in the granite is the largest, the feldspar is the second, the mica is the smallest. The main mineral contents in granite were analyzed using the semiquantitative method by XRD and the rock slice identification test. The elastic modulus and the Poisson ratio of granite calculated by three linear homogenization methods are consistent with those of the uniaxial compression test. After comparing the calculation results of the three methods, it is found that the Mori-Tanaka method is more suitable for studying the mechanical properties of rock materials. This method has an important theoretical significance and practical value for studying the quantitative relationship between macro- and micromechanical indexes of brittle materials. The research results provide a new method and an important reference for studying the macro-, micro-, and nanomechanical properties of rock.

scholarly journals Experimental and Numerical Evaluation of Progressive Collapse Behavior in Scaled RC Beam-Column Subassemblage

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Rasool Ahmadi ◽  
Omid Rashidian ◽  
Reza Abbasnia ◽  
Foad Mohajeri Nav ◽  
Nima Usefi
Keyword(s):  
Numerical Model ◽  
Progressive Collapse ◽  
Experimental Tests ◽  
Resistance Mechanisms ◽  
Full Scale ◽  
Displacement Curve ◽  
Rc Beam ◽  
Rc Structures ◽  
Collapse Behavior ◽  
Column Removal Scenario

An experimental test was carried out on a 3/10 scale subassemblage in order to investigate the progressive collapse behavior of reinforced concrete (RC) structures. Investigation of alternative load paths and resistance mechanisms in scaled subassemblage and differences between the results of full-scale and scaled specimens are the main goals of this research. Main characteristics of specimen response including load-displacement curve, mechanism of formation and development of cracks, and failure mode of the scaled specimen had good agreement with the full-scale specimen. In order to provide a reliable numerical model for progressive collapse analysis of RC beam-column subassemblages, a macromodel was also developed. First, numerical model was validated with experimental tests in the literature. Then, experimental results in this study were compared with validated numerical results. It is shown that the proposed macromodel can provide a precise estimation of collapse behavior of RC subassemblages under the middle column removal scenario. In addition, for further evaluation, using the validated numerical model, parametric study of new subassemblages with different details, geometric and boundary conditions, was also done.

Estimation of transverse tensile behavior of Zircaloy pressure tubes using ring-tensile test and finite element analysis

2012 ◽  
Vol 227 (6) ◽  
pp. 1177-1186 ◽  
Author(s):  
MK Samal ◽  
KS Balakrishnan ◽  
J Parashar ◽  
GP Tiwari ◽  
S Anantharaman
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Tensile Tests ◽  
Tensile Specimen ◽  
Displacement Curve ◽  
Stress Strain ◽  
Element Analysis ◽  
Transverse Tensile ◽  
Pressure Tubes ◽  
Load Displacement

Determination of transverse mechanical properties from the ring type of specimens directly machined from the nuclear reactor pressure tubes is not straightforward. It is due to the presence of combined membrane as well as bending stresses arising in the loaded condition because of the curvature of the specimen. These tubes are manufactured through a complicated process of pilgering and heat treatment and hence, the transverse properties need to be determined in the as-manufactured condition. It may not also be possible to machine small miniaturized specimen in the circumferential direction especially in the irradiated condition. In this work, we have performed ring-tensile tests on the un-irradiated ring tensile specimen using two split semi-cylindrical mandrels as the loading device. A three-dimensional finite element analysis was performed in order to determine the material true stress–strain curve by comparing experimental load–displacement data with those predicted by finite element analysis. In order to validate the methodology, miniaturized tensile specimens were machined from these tubes and tested. It was observed that the stress–strain data as obtained from ring tensile specimen could describe the load–displacement curve of the miniaturized flat tensile specimen very well. However, it was noted that the engineering stress–strain as directly obtained from the experimental load–displacement curves of the ring tensile tests were very different from that of the miniaturized specimen. This important aspect has been resolved in this work through the use of an innovative type of 3-piece loading mandrel.

scholarly journals Canine Vertebral Screw and Rod Fixation System: Design and Mechanical Testing

2018 ◽  
Vol 31 (02) ◽  
pp. 095-101 ◽  
Author(s):  
Nirut Suwanna ◽  
Björn Meij ◽  
Pakthorn Lewchalermwong
Keyword(s):  
Ultimate Load ◽  
Rapid Prototype ◽  
Biomechanical Properties ◽  
Bending Stiffness ◽  
Displacement Curve ◽  
Connecting Rod ◽  
Mean Values ◽  
Yield Load ◽  
Load Displacement ◽  
Fixation System

Objectives To develop the canine vertebral screw and rod fixation system (CVSRF) and to compare the biomechanical properties between CVSRF and the screw and polymethylmethacrylate (Screw-PMMA) technique for internal fixation of the vertebral column in dogs. Methods The CVSRF consisted of vertebral screws with monoaxial side-loaded head, rods and specific inner screws connecting rod to the screw head. The CVSRF prototype was made from titanium alloy and manufactured by the rapid prototype machine. Vertebrectomy models were simulated by ultra-high-molecular-weight polyethylene blocks and tested with the CVSRF system (n = 8) and the Screw-PMMA technique (n = 8). The models were developed according to the American Society for Testing and Materials (ASTM F-1717–04). The biomechanical parameters were the compressive bending yield load, the compressive bending stiffness, the compressive ultimate load and the load displacement curve. Results The mean values of the compressive bending yield load, compressive bending stiffness and compressive ultimate load of the CVSRF were significantly higher than those of the Screw-PMMA technique (p < 0.01). The load displacement curve of the CVSRF showed higher rigidity and durability than that of the Screw-PMMA technique. Clinical Significance This mechanical study indicated that the CVSRF system can be used for canine vertebral stabilization and the biomechanical properties were better than those for the Screw-PMMA device.

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