scholarly journals A 3D FEM Mesoscale Numerical Analysis of Concrete Tensile Strength Behaviour

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Chao Guo ◽  
Zhengran Lu
Keyword(s):  
Numerical Analysis ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Aggregate Size ◽  
Maximum Aggregate Size ◽  
Tensile Behaviour ◽  
Cohesive Element ◽  
3D Fem ◽  
3D Finite Element Method

A three-dimensional (3D) finite element method (FEM) based on an inserted cohesive element numerical analysis procedure was developed for concrete mesoscale systems on the ABAQUS platform with python scripts. Aggregates were generated based on dividing the existing geometrical element algorithms to randomize arbitrary spheres. Simultaneously, randomizations of the maximum aggregate size and uniform distributions of aggregate particles were also considered. An FEM for the mortar phase in concrete mesoscale systems was generated along with the interfacial transition zone (ITZ) by inserting a cohesive element. Numerical parameter analyses were performed for nine different concrete systems by varying the coarse aggregate volume fraction (α) and the ITZ tension strength (ITZ-S). The mechanical performance of concrete systems with the coupling effects of α and ITZ-S was evaluated for simulated tensile loading. The results of the numerical simulations for mechanical properties, such as the simulated tensile strengths and tension damage behaviour of concrete systems, were verified with experimental results. The proposed aggregate and ITZ generation approach and numerical simulation procedure can be used by researchers to better understand how aggregate volume fraction and ITZ strength affect the tensile behaviour of concrete mesoscale systems.

Flexible Pipes: Influence of the Pressure Armor in the Wet Collapse Resistance

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Alfredo Gay Neto ◽  
Clóvis de Arruda Martins
Keyword(s):  
Three Dimensional ◽  
External Pressure ◽  
Flexible Pipe ◽  
3D Fem ◽  
Collapse Pressure ◽  
Flexible Pipes ◽  
Polymeric Layer ◽  
Set Up ◽  
3D Finite Element Method ◽  
Ring Approximation

When submitted to high external pressure, flexible pipes may collapse. If the external sheath is damaged, all the external pressure is directly applied on the internal polymeric layer that transmits the loading to the carcass layer, which can fail due to this effect, leading to wet collapse. This failure mode must be taken into account in a flexible pipe design. A model can be set up neglecting the influence of the pressure armor, but this assumption may underestimate the wet collapse pressure value. This work aims to include the pressure armor effect in the numerical prediction of wet collapse. The main contribution of the pressure armor to the flexible pipe resistance to collapse is to be a constraint to the radial displacement of the carcass and the internal polymeric layers. Two models were developed to find the wet collapse pressure in flexible pipes. A first study was done using a ring approximation three-dimensional (3D) finite element method (FEM) model. Comparisons are made with more simplified models using a 3D FEM equivalent ring approximation. The aim is to clarify the mechanical behavior of the pressure armor in the wet collapse scenario. Parametric studies of initial ovalization of carcass and initial gaps and interference between polymeric layer and pressure armor are made and discussed.

Numerical Analysis of Erosive Wear on the Guide Vanes of a Francis Turbine

2015 ◽  
Vol 741 ◽  
pp. 531-535
Author(s):  
Hong Ming Zhang ◽  
Li Xiang Zhang
Keyword(s):  
Numerical Analysis ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Erosive Wear ◽  
Francis Turbine ◽  
Two Phase ◽  
Guide Vanes ◽  
Flow Equations ◽  
Sand Erosion ◽  
Volume Method

The paper presents the numerical analysis of erosive wear on the guide vanes of a Francis turbine using CFD code. The 3-D turbulent particulate-liquid two-phase flow equations are employed in this study. The computing domain is discretized with a full three-dimensional mesh system of unstructured tetrahedral shapes. The finite volume method is used to solve the governing equations and the pressure-velocity coupling is handled via a Pressure Implicit with Splitting of Operators (PISO) procedure. Simulation results have shown that the volume fraction of sand at the top of the guide vanes is higher than others and the maximum of volume fraction of sand is at same location with the maximum of sand erosion rate density. The erosive wear is more serious at the top of the guide vanes.

Investigation into tensile strength of noncrimp three-dimensional orthogonal woven structure

2018 ◽  
Vol 49 (2) ◽  
pp. 200-218
Author(s):  
Shohreh Minapoor ◽  
Saeed Ajeli ◽  
Mahdi Salmani Tehrani
Keyword(s):  
Tensile Strength ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Carbon Composite ◽  
Woven Fabric ◽  
Stress Wave Propagation ◽  
Compression Tests ◽  
Fiber Volume ◽  
Composite Reinforcements

Noncrimp three-dimensional orthogonal carbon weave is a specific type of three-dimensional woven fabric which is expected to have high performance as composite reinforcement. In this paper, two different orthogonal weaves in terms of carbon fiber tow type and binder yarns insertion density are produced, and a comprehensive study on the tensile strength of carbon composite reinforcements is conducted. The fiber volume fraction and mechanical performance are found to be affected by these two weave parameters. The fabric architecture changes due to different binder yarns’ insertion densities, influencing the stress wave propagation by preventing crack growth, thus leading to improve tensile strength of three-dimensional orthogonal reinforcement. Based on experimental weave parameters, a set of numerical compression tests are simulated by using a meso-scale finite element model. The results show that the model can predict the tensile strength of noncrimp three-dimensional orthogonal carbon composite reinforcements.

scholarly journals Evaluation of Tensile Properties and Damage of Continuous Fibre Reinforced 3D-Printed Parts

2018 ◽  
Vol 774 ◽  
pp. 161-166 ◽  
Author(s):  
Octavio Andrés González-Estrada ◽  
Alberto Pertuz ◽  
Jabid E. Quiroga Mendez
Keyword(s):  
3D Printing ◽  
Tensile Properties ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Tensile Tests ◽  
Fused Deposition Modelling ◽  
Printing Process ◽  
Fused Deposition ◽  
3D Printed

Three-dimensional (3D) printing technology has been traditionally used for the production of prototypes. Recently, developments in 3D printing using Fused Deposition Modelling (FDM) and reinforcement with continuous fibres (fiberglass and carbon fibre), have allowed the manufacture of functional prototypes, considerably improving the mechanical performance of the composite parts. In this work, we characterise the elastic tensile properties of fibre reinforced specimens, considering the variation of several parameters available during the printing process: fibre orientation, volume fraction, fill pattern, reinforcement distribution. Tensile tests were performed according to ASTM D638 to obtain Young’s modulus and ultimate strength for different material configurations available during the printing process. We also perform a fractographic analysis using Scanning Electron Microscopy (SEM) to give an insight of the failure mechanisms present in the specimens.

Implications of Including Reclaimed Asphalt Pavement Materials to Performance of Balanced Asphalt Concrete Mixes

2019 ◽  
Vol 2673 (12) ◽  
pp. 670-678 ◽  
Author(s):  
Luiza Barros ◽  
Victor M. Garcia ◽  
Jose Garibay ◽  
Imad Abdallah ◽  
Soheil Nazarian
Keyword(s):  
Asphalt Concrete ◽  
Mechanical Performance ◽  
Asphalt Pavement ◽  
Aggregate Size ◽  
Mix Design ◽  
Maximum Aggregate Size ◽  
Reclaimed Asphalt Pavement ◽  
Recycled Materials ◽  
Reclaimed Asphalt ◽  
Interaction Diagram

Understanding the effect of reclaimed asphalt pavement (RAP) on the mechanical performance of asphalt concrete (AC) mixtures may lead to improved mix design aiming to maximize the use of recycled materials while yielding optimal volumetric properties and balanced performance. This paper presents an experimental evaluation of the RAP content and source on the mechanical performance of AC mixes as measured by overlay tester, Hamburg wheel tracking device, and indirect tension tests. Several Superpave mixes with 12.5 mm nominal maximum aggregate size and recycled binder replacement ratios ranging from 0 to over 50 were designed and evaluated in this study. A performance interaction diagram was used to interpret collectively the cracking susceptibility, rutting potential, and tensile strength of the AC mixes. Asphalt concrete mixes with high RAP content can be balanced with proper individual mix design and their performance assessed through mechanical characterization. Furthermore, AC mixes with RAP from different sources yielded different cracking and rutting potentials. The performance tests and analysis methodology from this study could potentially be incorporated into the balanced mix design process to provide well-performing mixes containing optimal amounts for recycled materials.

Instrumentation For Quantitative Microscopy

1977 ◽  
Vol 35 ◽  
pp. 206-209
Author(s):  
B. Ralph ◽  
A.R. Jones
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Automatic Data ◽  
Phase Volume Fraction ◽  
Statistical Confidence ◽  
Resultant Data ◽  
Automatic Data Collection ◽  
Third Dimension ◽  
Evolution Of Microstructure

In all fields of microscopy there is an increasing interest in the quantification of microstructure. This interest may stem from a desire to establish quality control parameters or may have a more fundamental requirement involving the derivation of parameters which partially or completely define the three dimensional nature of the microstructure. This latter categorey of study may arise from an interest in the evolution of microstructure or from a desire to generate detailed property/microstructure relationships. In the more fundamental studies some convolution of two-dimensional data into the third dimension (stereological analysis) will be necessary.In some cases the two-dimensional data may be acquired relatively easily without recourse to automatic data collection and further, it may prove possible to perform the data reduction and analysis relatively easily. In such cases the only recourse to machines may well be in establishing the statistical confidence of the resultant data. Such relatively straightforward studies tend to result from acquiring data on the whole assemblage of features making up the microstructure. In this field data mode, when parameters such as phase volume fraction, mean size etc. are sought, the main case for resorting to automation is in order to perform repetitive analyses since each analysis is relatively easily performed.

Three dimensional numerical analysis of heat transfer during spray quenching of 22MnB5 steel with a single nozzle

2020 ◽  
Author(s):  
Emre Bulut ◽  
Gökhan Sevilgen ◽  
Ferdi Eşiyok ◽  
Ferruh Öztürk ◽  
Tuğçe Turan Abi
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Three Dimensional ◽  
22Mnb5 Steel

scholarly journals Is Micro X-ray Computer Tomography a Suitable Non-Destructive Method for the Characterisation of Dental Materials?

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1271
Author(s):  
Andreas Koenig ◽  
Leonie Schmohl ◽  
Johannes Scheffler ◽  
Florian Fuchs ◽  
Michaela Schulz-Siegmund ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Computer Tomography ◽  
Mechanical Performance ◽  
Dental Materials ◽  
Three Dimensional ◽  
X Rays ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Multiple Measurements ◽  
High Doses

The aim of the study was to investigate the effect of X-rays used in micro X-ray computer tomography (µXCT) on the mechanical performance and microstructure of a variety of dental materials. Standardised bending beams (2 × 2 × 25 mm3) were forwarded to irradiation with an industrial tomograph. Using three-dimensional datasets, the porosity of the materials was quantified and flexural strength was investigated prior to and after irradiation. The thermal properties of irradiated and unirradiated materials were analysed and compared by means of differential scanning calorimetry (DSC). Single µXCT measurements led to a significant decrease in flexural strength of polycarbonate with acrylnitril-butadien-styrol (PC-ABS). No significant influence in flexural strength was identified for resin-based composites (RBCs), poly(methyl methacrylate) (PMMA), and zinc phosphate cement (HAR) after a single irradiation by measurement. However, DSC results suggest that changes in the microstructure of PMMA are possible with increasing radiation doses (multiple measurements, longer measurements, higher output power from the X-ray tube). In summary, it must be assumed that X-ray radiation during µXCT measurement at high doses can lead to changes in the structure and properties of certain polymers.

scholarly journals Investigations of polyethylene of raised temperature resistance service performance using autoclave test under sour medium conditions

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 346-354
Author(s):  
Guoquan Qi ◽  
Hongxia Yan ◽  
Dongtao Qi ◽  
Houbu Li ◽  
Lushi Kong ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Mechanical Performance ◽  
Three Dimensional ◽  
Service Performance ◽  
Degree Of Branching ◽  
Temperature Resistance ◽  
Temperature Conditions ◽  
Dimensional Network ◽  
Gas Medium ◽  
Better Than

Abstract The chapter deals with the performance evaluation of the polyethylene of raised temperature resistance (PE-RT) and polyethylene (PE) using autoclave test under sour oil and gas medium conditions. The analyses of performance changes showed that PE-RT has good media resistance at 60°C. As the temperature increases, its mechanical properties decrease, accompanied by an increase in weight. Comparative analyses showed that no matter what temperature conditions are, PE-RT media resistance is better than PE80. The better media resistance of PE-RT depends on its higher degree of branching. Short branches are distributed between the crystals to form a connection between the crystals, thereby improving its heat resistance and stress under high-temperature conditions. PE-RT forms an excellent three-dimensional network structure through copolymerization, ensuring that it has better media resistance than PE80. However, the mechanical performance will be attenuated due to the high service temperature.

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