scholarly journals Composite beams with indented construction joint – comparison of results of laboratory tests and numerical analysis

2020 ◽  
Vol 19 (4) ◽  
pp. 031-042
Author(s):  
Grzegorz Sadowski ◽  
Piotr Wiliński ◽  
Anna Halicka
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Comparative Analysis ◽  
Composite Beam ◽  
Laboratory Tests ◽  
Virtual Model ◽  
Test Results ◽  
Shear Cracks ◽  
The Finite Element Method ◽  
Laboratory Test Results

The paper presents a comparative analysis of the behaviour of a composite beam, consisted of a precast element with indented surface and new concrete layer, subjected to 4-point bending. The results obtained from the virtual model of the beam created using the finite element method (Abaqus/CEA 2019 software) were compared with the laboratory test results obtained with use of the digital image correlation (DIC) method for identifying the crack pattern. The virtual model of composite beam was calibrated by the choice of interface parameters ensuring that the value of load resulting in delamination between concrete layers was close to that value obtained in the laboratory tests. The comparative analysis showed that the pattern of bending and shear cracks and the pattern of interface crack obtained with the finite element method reflect the laboratory test results properly. It can be assumed that the crack between concrete layers is related to the appearance and propagation of shear cracks. On the basis of FEM analysis it can be concluded that the phenomena identified as “shear friction” and “dowel action” are significantly activated after the interface cracking.

scholarly journals COMPARATIVE ANALYSIS OF MONOCORTICAL AND BICORTICAL METHODS OF INSTALLING MINI-IMPLANTS

2021 ◽  
pp. 38-40
Author(s):  
O.Yu. Rivis ◽  
V.S. Melnyk ◽  
M.V. Rivis ◽  
K.V. Zombor
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Comparative Analysis ◽  
Cortical Bone ◽  
Bone Tissue ◽  
Orthodontic Treatment ◽  
The Finite Element Method ◽  
Force Load ◽  
Mini Implants ◽  
Element Method

The aim of the study. Carry out a comparative analysis of the support ability of human jaw bone tissue in monocortical and bicortical installation of a mini-implant of own design OMG. Research methods. In order to study biomechanical characteristics of developed OMG mini-implant and bone tissue capacity during monocortical and bicortical installation, the finite element method (MSE) was used. The scheme and finite element 2-D model of bicortical installation of OMG mini-implant (length 8 mm, diameter 1.8 mm) provided full penetration through one layer of cortical bone equal to 1 mm, the entire cancellous bone and immersion in the second layer of cortical bone by 0, 5 mm. No implantation was immersed in the second cortical layer of bone during monocortical installation. A single force load of 1 N was applied in the horizontal direction parallel to the cortical plate of the bone. Results of the study. One of the most important factors leading to the success of the use of a mini-implant is its stability in the process of orthodontic treatment. Quite a high level of failure in the monocortical installation of mini-screws has led to the search for better methods to ensure the stability of their use. This was a bicortical method of fixation, based on the placement of the minig screw in the thickness of the two cortical plates of the jaws. Area for such installation of mini-screws can be a site of a palate and alveolar sprouts at installation of miniimplants through all its thickness. As shown by our data on the use of the finite element method under the force load of the biomechanical system "bone - mini-implant", the stress concentration zone is located in the area of the cortical bone of the jaw. The results of the calculation of the maximum stresses (σmax, MPa) and the maximum possible displacements (umax, mm) of the mini-implant in the biomechanical system "bone - mini-implant" in monocortical installation were, respectively, 8.27 MPa and 0.300 * 10-8 mm and in bicortical installation 6.00 MPa and 0.201 * 10-8 mm. The bicortical method of fixing the mini-implant in the jaw bones significantly increases the ability to resist deformation of this type of biomechanical system under force loads of the mini-implant. In the bicortical method of mini-implant placement, the extreme values of equivalent according to Mises stresses in the upper part of the cortical bone of the jaw are reduced by 27%. This can be explained by a significant increase in the area of contact due to the two layers of the cortical bone of the jaw with the surface of the mini-implant. Conclusion. The bicortical method of installing mini-implants is a more effective and reliable way to provide skeletal support during orthodontic treatment.

scholarly journals Analysis and Disposal of Typical Breakdown Failure for Resin Impregnated Paper Bushing in the Valve Side of HVDC Converter Transformer

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4303 ◽  
Author(s):  
Hao Tang ◽  
Guangning Wu ◽  
Ming Chen ◽  
Jiang Deng ◽  
Xining Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fault Current ◽  
Special Device ◽  
Test Results ◽  
The Finite Element Method ◽  
Load Current ◽  
High Voltage Direct Current ◽  
Root Cause ◽  
Current Characteristics

This paper presents analysis, diagnosis and disposal with a typical internal breakdown failure of the resin impregnated paper (RIP) valve side bushing in high voltage direct current (HVDC) converter transformer. Based on the analysis of fault current characteristics at the time of the RIP valve side bushing failure, and field test results of insulation parameters, a method of diagnosing typical breakdown failures of valve side bushings is proposed. Through disassembly inspection of the internal overheating and arcing traces on the failure bushing, the root cause of this typical breakdown failure is found, which is upper axial flashover along the RIP condenser/SF6 interface caused by the abnormal contact of two current-carrying conductive tubes. Temperature distribution inside the bushing with an abnormal contact resistance between the copper conductive tube and aluminum conductive tube under different load current is simulated by using the finite element method. An special device is also developed for repairing defective bushing on-site, and 75 bushings with conductive contact defects have been repaired on the premise of not pushing converter transformers away from the valve hall and even without pulling out defective bushings.

scholarly journals Analysis of crack propagation in a “pull-out” test

2019 ◽  
Vol 41 (3) ◽  
pp. 160-170
Author(s):  
Jakub Gontarz ◽  
Jerzy Podgórski
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Crack Propagation ◽  
Computer Analysis ◽  
Laboratory Tests ◽  
Crack Path ◽  
Rock Fragment ◽  
The Finite Element Method ◽  
Pull Out ◽  
Method Model

Abstract The article describes a computer analysis of the pull-out test used to calculate the force needed to pull out a rock fragment and determine the shape of this broken fragment. The analyzed material is sandstone and porphyry. The analysis included the first approach to using own subroutine in the Simulia Abaqus system, that is, which task is undertaken to accurately determine the crack path of the Finite Element Method model. The work also contains a description of laboratory tests and analytical considerations.

scholarly journals Comparative Analysis of Parallel Hybrid Magnet Memory Machines with Different PM Arrangements

2021 ◽  
Vol 12 (4) ◽  
pp. 177
Author(s):  
Yixian Wang ◽  
Hui Yang ◽  
Hao Zheng ◽  
Heyun Lin ◽  
Shukang Lyu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Comparative Analysis ◽  
Permanent Magnet ◽  
Magnetic Circuit ◽  
The Finite Element Method ◽  
Hybrid Magnet ◽  
Parallel Hybrid ◽  
Electromagnetic Characteristics ◽  
Magnetic Barriers

This paper presents a comparative analysis of two parallel hybrid magnet memory machines (PHMMMs) with different permanent magnet (PM) arrangements. The proposed machines are both geometrically characterized by a parallel U-shaped hybrid PM configuration and several q-axis magnetic barriers. The configurations and operating principles of the investigated machines are introduced firstly. The effect of magnet arrangements on the performance of the proposed machines is then evaluated with a simplified magnetic circuit model. Furthermore, the electromagnetic characteristics of the proposed machines are investigated and compared by the finite-element method (FEM). The experiments on one prototype are carried out to validate the FEM results.

scholarly journals Modeling and research of the process of preparing the surface of a part for thermal spray coating

2020 ◽  
Vol 329 ◽  
pp. 03052
Author(s):  
Aleksandr Novikov ◽  
Aleksei Rodishev ◽  
Andrei Gorin ◽  
Maria Tokmakova
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Comparative Analysis ◽  
Field Experiment ◽  
Adhesive Strength ◽  
Spray Coating ◽  
Thermal Spray Coating ◽  
The Finite Element Method ◽  
Antifriction Coating ◽  
Rolling Method

The article presents an analysis of ways to increase the adhesive strength of antifriction coating. A rational method for the mechanical formation of surfaces is proposed. The calculation of the workpiece based on the finite element method has been carried out. The theoretical dependences of metal lifting on the depth of the rolling roller are obtained. The results of a field experiment are presented. A comparative analysis of theoretical and practical results of the research has been carried out. Recommendations are given for the further use of the net rolling method with a pre-cut “ragged thread”.

Virtual Experimental Analyzes of the Normal and Arthrotic Hip

2020 ◽  
Vol 896 ◽  
pp. 3-14 ◽  
Author(s):  
Daniel Cosmin Calin ◽  
Dragos Laurentiu Popa ◽  
Alexandru Florian Grecu
Keyword(s):  
Computed Tomography ◽  
Finite Element Method ◽  
Finite Element ◽  
Hip Joint ◽  
Special Importance ◽  
Virtual Model ◽  
The Finite Element Method ◽  
Normal Walking ◽  
Tomographic Images ◽  
Main Components

The hip joint is spheroidal type which allows three movement axes, with a special importance in statics and locomotion. The study of the hip joint by computerized tomography of a male, 52-year-old male patient at the Craiova County Emergency Clinical Hospital was started using Siemens equipment comprised of a magnetic resonance device and a computed tomography apparatus. Were analyzed: hip joint with the two main components of the femur and pelvic bones. To obtain the virtual components of the hip joint, 143 tomographic images from different planes were analyzed. CT images were used to define the normal hip joint. Also, the arthrotic hip virtual model was generated. These two virtual models were subjected to normal walking load and were simulated by the finite element method. The results were analyzed and compared, and important conclusions were finally drawn.

Design of a 33-Knot Aluminum Catamaran Ferry

2000 ◽  
Vol 37 (02) ◽  
pp. 88-99
Author(s):  
R. G. Latorre ◽  
P. D. Herrington
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Speed ◽  
Frame Structure ◽  
Test Results ◽  
Finite Element Analyses ◽  
The Finite Element Method ◽  
Floating Frame ◽  
Good Agreement ◽  
Panel Design

This paper presents the results of an investigation on the suitability of using hull panels with alternating fixed and floating frames for a 30–40 knot aluminum catamaran ferry. A prototype 4.6 m × 1.8 m bottom hull panel with alternating frames is analyzed numerically and physically tested. The corresponding finite-element analyses and test results are in good agreement. The results show that the floating frame hull panel design is a feasible structure for an aluminum catamaran. The floating frame structure was then used for a 33-knot, 250-passenger aluminum catamaran ferry designed to meet the ABS High Speed Craft rules. A midship section of the catamaran hull was analyzed using the finite-element method. Catamaran weight estimates, heave and pitch motions, and powering estimates are also provided. The results show that the alternating floating frame structure was within the ABS rules stress allowables.

scholarly journals Assessment of the reinforcing ability of a composite bandage for modern pipeline repair systems

2021 ◽  
Author(s):  
Eugen Savchuk ◽  
Viktor Rubashevskyi ◽  
Sergiy Shukayev
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Comparative Analysis ◽  
Service Life ◽  
Close Agreement ◽  
The Finite Element Method ◽  
Strain Ageing ◽  
Term Operation ◽  
Reinforced Steel

Abstract. The long-term operation of pipelines, which, in many cases, exceeds their regulatory service life, causes the strain ageing of metal, as well as the appearance of local mechano-corrosive damages. In this regard, the use of composites to reinforce worn pipelines constitutes one of today’s most promising technologies. In this study, a comparative analysis was performed between the composite-reinforced steel pipe calculations that were conducted using the finite element method (FEM), and those that were conducted in accordance with the DSTU ISO 24817:2019 standard. The FEM numerical calculations were carried out using the complete factorial experiment design (consisting of three factors at three levels, with twenty-seven calculations in total). Based on the results of these calculations, a regression model was developed to assess the circular deformation of the pipe’s outer surface depending on the thickness of the bandage, the thickness of the pipe, and the internal pressure. The FEM calculations were found to be in close agreement with analytical results.

COMPARATIVE ANALYSIS OF THE SYSTEM APM WINMACHINE AND CAE ABAQUS FOR CALCULATING THE STRENGTH OF A WELDED JOINT

2020 ◽  
Vol 5 ◽  
pp. 28-32
Author(s):  
V.V. LEONTYEV ◽  
E.V. KONDRATOVA ◽  
V.P. KOLOMIYCHENKO
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Comparative Analysis ◽  
Strain State ◽  
Safety Margin ◽  
Operating Conditions ◽  
The Finite Element Method ◽  
Stress Strain ◽  
Stress Strain State ◽  
Element Method

Traditional methods for calculating welded joints are based on approximate methods for determining the forces that occur in the joint. This leads to inaccuracies in the definition of stress. In addition, this approach does not allow obtaining a complete picture of the stress-strain state of the joint. All this leads to the need to increase the coefficient of safety margin and, as a result, to increase the cost of construction. The proposed method of calculating the connection using the finite element method allows us to determine the stresses in all the elements of the connection very accurately. This makes it possible to obtain a reliable picture of the stress-strain state of all elements of the connection. As a result, it is possible to reduce the complexity of creating a compound and its mass. The finite element method should be used for calculating critical connections with complex operating conditions. An example of calculating such a connection is considered. A comparative analysis of the results of calculating the t-joint using the arm Joint module Of the WinMachine arm system and the Abaqus finite element package is performed.

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