scholarly journals BOND STRENGTH OF BAR USING GROUTING FOR PRECAST CONCRETE CONNECTION

2019 ◽  
Vol 1 (01) ◽  
pp. 1-9
Author(s):  
Anis Rosyidah ◽  
I Ketut Sucita ◽  
Praganif Sukarno ◽  
S. R. Permita Sari ◽  
Chintya Sari
Keyword(s):  
Finite Element Method ◽  
Bond Strength ◽  
Test Specimen ◽  
Precast Concrete ◽  
Second Phase ◽  
Strength Ratio ◽  
The Finite Element Method ◽  
Additional Material ◽  
Damage Pattern ◽  
Pullout Testing

In precast concrete, a connection is needed to unite the components so that they become a whole unified structure. This study aims to determine the reinforcement strength and length of reinforcement in precast concrete connections. To paste reinforcement into precast concrete, giving additional material in the form of grouting which is called sika grout 215 and functions as an adhesive is necessary. Pullout testing is carried out in the laboratory, and its simulation by modeling uses the finite element method based software. This research is divided into 2 phases. The first phase is making specimen to examine the bond strength between the concrete and reinforcement that has been given sika grout 215. So monolithic specimen is made as a comparison. The result of the bond strength of the monolithic test specimen is 6.24 MPa, and the sika grout 215 category is 6.52 MPa. From the experimental results in the laboratory with modeling, it is obtained the bond strength ratio of 0.94. The length of development (ld) based on the results of the testing phase I of 200 mm. The second phase is examining the damage pattern due to the stress that occurred. Specimens are made into 4 categories, namely modeling developments with the length of 120 mm (<40% ld), with the length of 160 mm (<20% ld), with length of 200 mm (= ld), and with the length of 260 mm(> 30% ld) both for monoliths and sika grout 215. The damage pattern, which is in the form of yielding and breaking reinforcement as the result of the pullout experiment in the laboratory shows not much different from the result of simulation using the software.

Failure mechanisms in two-layer undrained slopes

2020 ◽  
Vol 57 (10) ◽  
pp. 1617-1621
Author(s):  
Shuangfeng Guo ◽  
D.V. Griffiths
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Failure Mechanism ◽  
Failure Mechanisms ◽  
Slope Angle ◽  
Strength Ratio ◽  
The Finite Element Method ◽  
Stability Analyses ◽  
Shallow Failure ◽  
Insight Into

This note presents results of stability analyses of two-layer undrained slopes by the finite element method. The study focuses on the circumstances under which either deep or shallow failure mechanisms occur, as a function of the strength ratio of the layers, slope angle, and foundation depth ratio. Improved knowledge of the location of the critical failure mechanism(s) in two-layer systems will give engineers better insight into where to focus their attention in terms or remediation or reinforcement to preserve stability.

scholarly journals Application of Low-Cost Sensors for the Development of a Methodology to Design Front-End Loaders for Tractors

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
H. Malon ◽  
A. Ayuda ◽  
F. J. Garcia-Ramos ◽  
M. Vidal ◽  
J. Cuartero
Keyword(s):  
Finite Element Method ◽  
Low Cost ◽  
Strain Gauges ◽  
Second Phase ◽  
The Finite Element Method ◽  
Structural Behaviour ◽  
Experimental Phase ◽  
Front End ◽  
Accurate Design ◽  
Two Phases

Tractor front-end loaders are an essential part of the equipment used on farms. At present, there are an important number of small- and medium-sized companies involved in the manufacturing of this equipment. These companies rely heavily on experience for innovative designs, as in the vast majority of cases they lack access to adequate methodology for the optimal design of new front-end loaders. The study conducted has developed a methodology to design tractor front-end loaders with a view of obtaining their accurate design during the bucket loading process. The methodology comprises two phases: the first phase involves a numerical analysis of the structural behaviour of the front-end loader components by means of the Finite Element Method; the second phase, the experimental phase, makes use of low-cost sensors, in particular, strain gauges, to analyse existing strains at selected points in the front-end loader structure. The experimental results obtained by means of low-cost sensors fitted onto the front-end loader allow analysing the existing strains at the points measured, as well as validate the numerical model developed. This methodology is validated by applying it to a commercial front-end loader, more specifically to model 430E2 of the company Maquinaria Agrícola El León S.A (Spain).

Proposal of a test specimen to evaluate the shear strength of vertical interfaces of running bond masonry walls

2008 ◽  
Vol 35 (6) ◽  
pp. 567-573 ◽  
Author(s):  
Valentim Capuzzo Neto ◽  
Márcio R.S. Corrêa ◽  
Marcio A. Ramalho
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Shear Stress ◽  
Shear Strength ◽  
Test Specimen ◽  
Experimental Program ◽  
Masonry Walls ◽  
The Finite Element Method ◽  
Theoretical Performance ◽  
Loading Scheme

There is no normalized test to assess the shear strength of vertical interfaces of interconnected masonry walls. The approach used to evaluate this strength is normally indirect and often unreliable. The aim of this study is to propose a new test specimen to eliminate this deficiency. The main features of the proposed specimen are failure caused by shear stress on the vertical interface and a small number of units (blocks). The paper presents a numerical analysis based on the finite element method, with the purpose of showing the theoretical performance of the designed specimen, in terms of its geometry, boundary conditions, and loading scheme, and describes an experimental program using the specimen built with full- and third-scale clay blocks. The main conclusions are that the proposed specimen is easy to build and is appropriate to evaluate the shear strength of vertical interfaces of masonry walls.

scholarly journals The Strength of Egg Trays under Compression: A Numerical and Experimental Study

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2279
Author(s):  
Leszek Czechowski ◽  
Gabriela Kmita-Fudalej ◽  
Włodzimierz Szewczyk
Keyword(s):  
Finite Element Method ◽  
Experimental Study ◽  
Finite Element ◽  
Maximum Load ◽  
Experimental Investigations ◽  
Large Strains ◽  
Strength Ratio ◽  
The Finite Element Method ◽  
Compression Stiffness ◽  
Different Shapes

This work concerns the analysis of egg packages subjected to compression. Experimental investigations were carried out to determine the curves of compression and maximum loads. To compare packages accessible on the market, several different shapes of egg packages were tested after being conditioned in air with a relative humidity of 50%. Several paper structures in stock were compressed. By validating the experiment results, numerical computations based on the finite element method (FEM) were executed. The estimations of a numerical model were performed with the use of the perfect plasticity of paper and with the assumption of large strains and deflections. Our own two structures of egg packaging were taken into account: basic and modified. The material of the packages was composed of 90% recovered paper and 10% coconut fibres. This paper involved the numerical modelling of such complex packaging. Moreover, our research showed that introducing several features into the structures of the packaging can improve the stiffness and raise the maximum load. Thanks to the application of ribs and grooves, the strength ratio and compression stiffness, in comparison to the basic tray, increased by approximately 23.4% and 36%, respectively. Moreover, the obtained indexes of modified trays were higher than the majority of the studied market trays.

scholarly journals Optimization of the bending stiffness of beam-to-column and column-to-foundation connections in precast concrete structures

2017 ◽  
Vol 10 (5) ◽  
pp. 985-997
Author(s):  
R. R. R. COSTA ◽  
M. C. V. LIMA ◽  
G. M. S. ALVA ◽  
E. S. MAGALHÃES
Keyword(s):  
Finite Element Method ◽  
Global Stability ◽  
Precast Concrete ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Bending Stiffness ◽  
The Finite Element Method ◽  
Constraint Factors ◽  
Rigid Frames ◽  
Optimal Stiffness

Abstract This work involved the structural optimization of precast concrete rigid frames with semi-rigid beam-to-column connections. To this end, several frames were simulated numerically using the Finite Element Method. Beams and columns were modeled using bar elements and their connections were modeled using spring elements, with variable bending stiffness. The objective function was based on the search of the least stiff connection able to ensure the global stability of the building. Lastly, a connection model with optimal stiffness was adopted to design the frame. Semi-rigid beam-to-column connections with a constraint factors of 0.33 sufficed to ensure the maximum allowable horizontal displacement and bending moment of the connection, with a global stability parameter of 1.12. This confirms that even connections with low constraints generate significant gains from the structural standpoint, without affecting construction and assembly-related aspects.

Effects of Shape and Bond Strength on Adhesive Failure of Joint Sealants

2020 ◽  
pp. 036119812096209
Author(s):  
Jinho Kim ◽  
Dan Zollinger
Keyword(s):  
Finite Element Method ◽  
Bond Strength ◽  
Shape Factor ◽  
Joint Strength ◽  
The Finite Element Method ◽  
Adhesive Failure ◽  
Design Factor ◽  
Joint Preparation ◽  
The Face ◽  
Bond Tests

Currently, joint sealant is designed without consideration of the bond strength between the concrete and the sealant and the effect of shape on stress concentration. This often leads to adhesive failures within 1.5 years, earlier than the expected service life of the joint sealant, which is 20 years. In adhesive failure, the strength of the bond and the stress of the interface between the sealant and the face of the joint reservoir play a very important role. To examine the nature of the bond along the sealant/joint well interface, experimental bond tests were conducted. In addition, the stress distribution on the interface was also investigated according to geometry (Shape Factor [SF] and degree of curvature [DoC]). Re-evaluation of the SF was conducted, and a new design factor, DoC, was introduced and investigated through the finite element method of analysis. With these factors, the reduction of bond strength and increase in the stress at the interface can be limited reducing the potential for early adhesive failure. Based on this study, the effect of joint preparation (dirt and moisture) on joint strength and shape (SF and DoC) of joint sealant should be considered when designing and installing sealants.

scholarly journals Numerical Evaluation of Settlement of Strip Footing Resting on Cavity and Weak Soil Profile

2021 ◽  
Vol 11 (1) ◽  
pp. 87-97
Author(s):  
Mohammed S. Hussain
Keyword(s):  
Finite Element Method ◽  
Soil Profile ◽  
Numerical Evaluation ◽  
Critical Zone ◽  
Strip Footing ◽  
Risk Level ◽  
Second Phase ◽  
The Finite Element Method ◽  
Weak Soil ◽  
Low Stiffness

This study numerically investigates the effects of different subsurface sources of weaknesses within a soil profile on the settlement of a strip footing using the finite element method (FEM). During the first phase of the study, the influences of size, shape, depth, and distance of cavity from the center of the footing are evaluated. It is noted that the settlement of foundation is increased when the cavity is located at smaller depths and closer to its center. It is concluded that there is a critical zone, where the risk level of settlement (especially differential settlement) due to the cavity is high. The depth of this critical zone is found to be 2.5B (where B is the width of the footing) below the simulated loading area. In the second phase of the study, increasing the degree of weakness of a certain low stiffness layer within the soil profile below the loaded area is simulated as another factor that increases the settlement risks. It is shown that the depth of this weak layer highly controls the settlement of footing even if it is situated at depths >2.5B.

Simulation of tuning graphene plasmonic behaviors by ferroelectric domains for self-driven infrared photodetector applications

Nanoscale ◽  
2019 ◽  
Vol 11 (43) ◽  
pp. 20868-20875 ◽  
Author(s):  
Junxiong Guo ◽  
Yu Liu ◽  
Yuan Lin ◽  
Yu Tian ◽  
Jinxing Zhang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Interfacial Effect ◽  
Infrared Photodetector ◽  
The Finite Element Method ◽  
Ferroelectric Domains ◽  
Element Method

We propose a graphene plasmonic infrared photodetector tuned by ferroelectric domains and investigate the interfacial effect using the finite element method.

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