Effect of Loading Rate and Pipe Wall Thickness on the Strength and Toughness of Welded and Unwelded Polyethylene Pipes

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Tarek M. A. A. EL-Bagory ◽  
Hossam E. M. Sallam ◽  
Maher Y. A. Younan
Keyword(s):  
Mechanical Behavior ◽  
Mechanical Characteristics ◽  
Tensile Tests ◽  
Primary Objective ◽  
Design Data ◽  
Practical Applications ◽  
Polyethylene Pipes ◽  
Gauge Section ◽  
Reliable Design ◽  
Hdpe Pipes

Abstract The primary objective of this paper is to depict the mechanical behavior of welded and unwelded high-density polyethylene (HDPE), pipes to provide the designer with reliable design data relevant to practical applications. Therefore, it is necessary to study the effect of strain rate and specimen configuration on the mechanical behavior of welded and unwelded pipes made from HDPE. Tensile tests are conducted on specimens longitudinally cut from the pipe with thickness (10 and 30 mm), at different crosshead speeds (5–500 mm/min), and different gauge lengths (20, 25, and 50 mm) to investigate the mechanical properties of welded and unwelded specimens. All tests are performed at room temperature (Ta = 23 °C). Butt fusion, BF, welding method is used to join the different parts of HDPE pipes. The present results showed that the mechanical characteristics of welded specimens are lower than those of unwelded specimens. In the case of test specimens taken from unwelded pipe, the results of mechanical characteristics revealed that a necking phenomenon before failure appears at different locations along the gauge section. On the other hand, the fracture of welded specimens almost occurs at the fusion zone. It is found that the crosshead speed and specimen configurations have a significant effect on the mechanical behavior of both welded and unwelded specimens.

Mechanical Behavior of Welded and Un-Welded Polyethylene Pipe Materials

2013 ◽  
Author(s):  
Tarek M. A. A. El-Bagory ◽  
Maher Y. A. Younan ◽  
Hossam E. M. Sallam
Keyword(s):  
Mechanical Behavior ◽  
Fusion Zone ◽  
Tensile Tests ◽  
Primary Objective ◽  
Design Data ◽  
Practical Applications ◽  
Gauge Section ◽  
Reliable Design ◽  
Welded Pipe ◽  
Hdpe Pipes

The primary objective of the present paper is to depict the mechanical behavior of high density polyethylene, HDPE, pipes to provide the designer with reliable design data relevant to practical applications. Therefore, it is necessary to study the effect of strain rate and specimen configuration on the mechanical behavior of welded and un-welded pipes made from HDPE. Tensile tests are conducted on specimens longitudinally cut from the pipe with thickness (10, and 30 mm), at different crosshead speeds (5–500 mm/min), and different gauge lengths (20, 25, and 50 mm) to investigate the mechanical properties of welded and un-welded specimens. Butt-fusion, BF, welding method is used to join the different parts of HDPE pipes. In the case of test specimens taken from un-welded pipe a necking phenomenon before failure appears at different locations along the gauge section. On the other hand, the fracture of welded specimens almost occurs at the fusion zone. At lower crosshead speeds the fracture of welded specimen occurs in all specimen configurations at the fusion zone. The present experimental work reveals that the crosshead speed has a significant effect on the mechanical behavior of both welded and un-welded specimens.

Effect of Specimen Geometry on the Predicted Mechanical Behavior of Polyethylene Pipe Material1

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Tarek M. A. A. EL-Bagory ◽  
Tawfeeq A. R. Alkanhal ◽  
Maher Y. A. Younan
Keyword(s):  
Mechanical Behavior ◽  
Longitudinal Direction ◽  
Tensile Tests ◽  
Primary Objective ◽  
The Other ◽  
Pipe Material ◽  
Design Data ◽  
Practical Applications ◽  
Other Hand ◽  
Gauge Section

The primary objective of the present paper is to depict the mechanical behavior of high density polyethylene (HDPE) pipes under different loading conditions with different specimen geometries to provide the designer with reliable design data relevant to practical applications. Therefore, it is necessary to study the effect of strain rate, ring configuration, and grip or fixture type on the mechanical behavior of dumb-bell-shaped (DBS), and ring specimens made from HDPE pipe material. DBS and ring specimens are cut from the pipe in longitudinal and circumferential (transverse) directions, respectively. On the other hand, the ring specimen configuration is classified into two types; full ring (FR), and notched ring (NR) (equal double notch from two sides of NR specimen) specimens according to ASTM D 2290-12 standard. Tensile tests are conducted on specimens cut out from the pipe with thickness of 10 mm at different crosshead speeds (10–1000 mm/min), and ambient temperature, Ta = 20 °C to investigate the mechanical properties of DBS and ring specimens. In the case of test specimens taken from the longitudinal direction from the pipe, a necking phenomenon before failure appears at different locations along the gauge section. On the other hand, the fracture of NR specimens occurs at one notched side. The results demonstrated that the NR specimen has higher yield stress than DBS and FR specimens at all crosshead speeds. The present experimental work reveals that the crosshead speed has a significant effect on the mechanical behavior of both DBS and ring specimens. The fixture type plays an important role in the mechanical behavior for both FR and NR specimens at all crosshead speeds.

Effect of Specimen Geometry on the Predicted Mechanical Behavior of Polyethylene Pipe Material

2014 ◽  
Author(s):  
Tarek M. A. A. El-Bagory ◽  
Tawfeeq A. R. Alkanhal ◽  
Maher Y. A. Younan
Keyword(s):  
Mechanical Behavior ◽  
Longitudinal Direction ◽  
Primary Objective ◽  
The Other ◽  
Pipe Material ◽  
Ring Specimen ◽  
Design Data ◽  
Practical Applications ◽  
Other Hand ◽  
Gauge Section

The primary objective of the present paper is to depict the mechanical behavior of high density polyethylene, (HDPE), pipes under different loading conditions with different specimen geometries to provide the designer with reliable design data relevant to practical applications. Therefore, it is necessary to study the effect of strain rate, ring configuration, and grip or fixture type on the mechanical behavior of dumb-bell-shaped, (DBS), and ring specimens made from HDPE pipe material. DBS and ring specimens are cut from the pipe in longitudinally, and circumferential (transverse) direction respectively. On the other hand, the ring specimen configuration is classified into two types; full ring, (FR), and notched ring, (NR) (equal double notch from two sides of notched ring specimen) specimens according to ASTM D 2290-12 standard. Tensile tests are conducted on specimens cut out from the pipe with thickness 10 mm at different crosshead speeds (10–1000 mm/min), and ambient temperature, Ta = 20 °C to investigate the mechanical properties of DBS, and ring specimens. In the case of test specimens taken from longitudinal direction from the pipe a necking phenomenon before failure appears at different locations along the gauge section. On the other hand, the fracture of NR specimens occurs at one notched side. The results demonstrated that the NR specimen has higher yield stress than DBS, and FR specimens at all crosshead speeds. The present experimental work reveals that the crosshead speed has a significant effect on the mechanical behavior of both DBS, and ring specimens. The fixture type plays an important role in the mechanical behavior for both FR and NR specimens at all crosshead speeds.

Analysis of Non-Linear Activation Functions for Classification Tasks Using Convolutional Neural Networks

2019 ◽  
Vol 12 (3) ◽  
pp. 156-161 ◽  
Author(s):  
Aman Dureja ◽  
Payal Pahwa
Keyword(s):  
Neural Networks ◽  
Deep Neural Networks ◽  
Activation Function ◽  
Primary Objective ◽  
Experimental Comparison ◽  
Activation Functions ◽  
Practical Applications ◽  
Network Activation ◽  
Non Linear ◽  
Hidden Layer

Background: In making the deep neural network, activation functions play an important role. But the choice of activation functions also affects the network in term of optimization and to retrieve the better results. Several activation functions have been introduced in machine learning for many practical applications. But which activation function should use at hidden layer of deep neural networks was not identified. Objective: The primary objective of this analysis was to describe which activation function must be used at hidden layers for deep neural networks to solve complex non-linear problems. Methods: The configuration for this comparative model was used by using the datasets of 2 classes (Cat/Dog). The number of Convolutional layer used in this network was 3 and the pooling layer was also introduced after each layer of CNN layer. The total of the dataset was divided into the two parts. The first 8000 images were mainly used for training the network and the next 2000 images were used for testing the network. Results: The experimental comparison was done by analyzing the network by taking different activation functions on each layer of CNN network. The validation error and accuracy on Cat/Dog dataset were analyzed using activation functions (ReLU, Tanh, Selu, PRelu, Elu) at number of hidden layers. Overall the Relu gave best performance with the validation loss at 25th Epoch 0.3912 and validation accuracy at 25th Epoch 0.8320. Conclusion: It is found that a CNN model with ReLU hidden layers (3 hidden layers here) gives best results and improve overall performance better in term of accuracy and speed. These advantages of ReLU in CNN at number of hidden layers are helpful to effectively and fast retrieval of images from the databases.

scholarly journals Mimicking the Mechanical Properties of Aortic Tissue with Pattern-Embedded 3D Printing for a Realistic Phantom

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5042
Author(s):  
Jaeyoung Kwon ◽  
Junhyeok Ock ◽  
Namkug Kim
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
3D Printing ◽  
Mechanical Characteristics ◽  
Aortic Wall ◽  
Tensile Tests ◽  
Human Aorta ◽  
Aortic Tissue ◽  
Medical Field ◽  
Base Materials

3D printing technology has been extensively applied in the medical field, but the ability to replicate tissues that experience significant loads and undergo substantial deformation, such as the aorta, remains elusive. Therefore, this study proposed a method to imitate the mechanical characteristics of the aortic wall by 3D printing embedded patterns and combining two materials with different physical properties. First, we determined the mechanical properties of the selected base materials (Agilus and Dragonskin 30) and pattern materials (VeroCyan and TPU 95A) and performed tensile testing. Three patterns were designed and embedded in printed Agilus–VeroCyan and Dragonskin 30–TPU 95A specimens. Tensile tests were then performed on the printed specimens, and the stress-strain curves were evaluated. The samples with one of the two tested orthotropic patterns exceeded the tensile strength and strain properties of a human aorta. Specifically, a tensile strength of 2.15 ± 0.15 MPa and strain at breaking of 3.18 ± 0.05 mm/mm were measured in the study; the human aorta is considered to have tensile strength and strain at breaking of 2.0–3.0 MPa and 2.0–2.3 mm/mm, respectively. These findings indicate the potential for developing more representative aortic phantoms based on the approach in this study.

Mechanical Behavior for some Cobalt Alloys

2015 ◽  
Vol 1114 ◽  
pp. 9-12
Author(s):  
Alexandru Ghiban ◽  
Brandusa Ghiban ◽  
Cristina Maria Borţun ◽  
Nicolae Serban ◽  
Mihai Buzatu
Keyword(s):  
Tensile Strength ◽  
Chemical Composition ◽  
Mechanical Behavior ◽  
Mechanical Characteristics ◽  
Fractographic Analysis ◽  
Cobalt Alloys ◽  
Dental Alloys ◽  
Bending Tests ◽  
Longitudinal Modulus

Four compositions of some usually commercial dental alloys were investigated in order to determine the mechanical characteristics and fractographic analysis of tensile and bending tests surfaces. A correlation between chemical composition (either molybdenum or molybdenum and chromium contents) and mechanical characteristics (longitudinal modulus, tensile strength and elongation) were finally done.

scholarly journals A Material Model for the Orthotropic and Viscous Behavior of Separators in Lithium-Ion Batteries under High Mechanical Loads

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4585
Author(s):  
Marian Bulla ◽  
Stefan Kolling ◽  
Elham Sahraei
Keyword(s):  
Mechanical Behavior ◽  
Lithium Ion ◽  
Material Model ◽  
Tensile Tests ◽  
Element Analysis ◽  
Rate Dependent ◽  
Novel Material ◽  
Li Ion ◽  
Role Based ◽  
Drive Systems

The present study is focused on the development of a material model where the orthotropic-visco-elastic and orthotropic-visco-plastic mechanical behavior of a polymeric material is considered. The increasing need to reduce the climate-damaging exhaust gases in the automotive industry leads to an increasing usage of electric powered drive systems using Lithium-ion (Li-ion) batteries. For the safety and crashworthiness investigations, a deeper understanding of the mechanical behavior under high and dynamic loads is needed. In order to prevent internal short circuits and thermal runaways within a Li-ion battery, the separator plays a crucial role. Based on results of material tests, a novel material model for finite element analysis (FEA) is developed using the explicit solver Altair Radioss. Based on this model, the visco-elastic-orthotropic, as well as the visco-plastic-orthotropic, behavior until failure can be modeled. Finally, a FE simulation model of the separator material is performed, using the results of different tensile tests conducted at three different velocities, 0.1 mm·s−1, 1.0 mm·s−1 and 10.0 mm·s−1 and different orientations of the specimen. The purpose is to predict the anisotropic, rate-dependent stiffness behavior of separator materials in order to improve FE simulations of the mechanical behavior of batteries and therefore reduce the development time of electrically powered vehicles and consumer goods. The present novel material model in combination with a well-suited failure criterion, which considers the different states of stress and anisotropic-visco-dependent failure limits, can be applied for crashworthiness FE analysis. The model succeeded in predicting anisotropic, visco-elastic orthotropic and visco-plastic orthotropic stiffness behavior up to failure.

Study Regarding the Influence of the Printing Orientation Angle on the Mechanical Behavior of Parts Manufactured by Material Jetting

2021 ◽  
Vol 58 (3) ◽  
pp. 198-209
Author(s):  
Vasile Cojocaru ◽  
Doina Frunzaverde ◽  
Dorian Nedelcu ◽  
Calin-Octavian Miclosina ◽  
Gabriela Marginean
Keyword(s):  
Additive Manufacturing ◽  
Rapid Prototyping ◽  
Tensile Test ◽  
Mechanical Behavior ◽  
Process Parameters ◽  
Orientation Angle ◽  
Tensile Tests ◽  
Anisotropic Behavior ◽  
Optimization Of Process Parameters ◽  
Printed Materials

Initially developed as a rapid prototyping tool for project visualization and validation, the recent development of additive manufacturing (AM) technologies has led to the transition from rapid prototyping to rapid manufacturing. As a consequence, increased attention has to be paid to the mechanical, chemical and physical properties of the printed materials. In mechanical engineering, the widespread use of AM technologies requires the optimization of process parameters and material properties in order to obtain components with high, repeatable and time-stable mechanical properties. One of the main problems in this regard is the anisotropic behavior of components made by additive manufacturing, determined by the type of material, the 3D printing technology, the process parameters and the position of the components in the printing space. In this paper the influence of the printing orientation angle on the tensile behavior of specimens made by material jetting is investigated. The aim was to determine if the positioning of components at different angles relative to the X-axis of the printer (and implicitly in relation to the multijet printing head) contributes to anisotropic behavior. The material used was a photopolymer with a mechanical strength between 40 MPa and 55 MPa, according to the producer. Four sets of tensile test specimens were manufactured, using flat build orientation and positioned on the printing table at angles of 0˚, 30˚, 60˚ and 90˚ to the X-axis of the printer. Comparative analysis of the mechanical behavior was carried out by tensile tests and microscopic investigations of the tensile test specimens fracture surfaces.

Mechanical and thermal behaviors of ultra-high molecular weight polyethylene triaxial braids: the influence of structural parameters

2018 ◽  
Vol 89 (16) ◽  
pp. 3362-3373 ◽  
Author(s):  
Shenglei Xiao ◽  
Charles Lanceron ◽  
Peng Wang ◽  
Damien Soulat ◽  
Hang Gao
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Mechanical Characteristics ◽  
Structural Parameters ◽  
Tensile Tests ◽  
Tensile Behavior ◽  
Experimental Database ◽  
Strength And Deformation ◽  
Braiding Angle ◽  
Ultra High Molecular Weight

Recently, triaxial braids made from ultra-high molecular weight polyethylene (UHMWPE) have been recognized as one of the most popular composite reinforcements in the aerospace and defense fields. To further explore the mechanical characteristics of this material, a detailed experimental study on tensile behavior is reported in this paper. The triaxial braids show a “double-peak” phenomenon in tensile strength and deformation, caused by axial yarns and the in-plane shearing of bias yarns. The evolution of the braiding angle, measured during these tensile tests, is discussed according to the braiding parameters (initial braiding angle, number of axial yarns). Using the high conductivity properties of the UHMWPE material, the temperature caused by inter-yarn friction during tensile tests is also studied. This temperature is related to the evolution of the braiding angle. The temperature increases with the increasing number of axial yarns and decreases with increasing braiding angle. This study provides an experimental database on the influence of braiding parameters on the tensile behavior of triaxial braids.

Superplastic Behavior of a Cu-Cr-Zr Alloy Subjected to ECAP

2016 ◽  
Vol 838-839 ◽  
pp. 404-409
Author(s):  
Roman Mishnev ◽  
Iaroslava Shakhova ◽  
Andrey Belyakov ◽  
Rustam Kaibyshev
Keyword(s):  
Grain Size ◽  
Dislocation Density ◽  
Strain Rate ◽  
Temperature Interval ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Superplastic Behavior ◽  
Average Grain Size ◽  
Gauge Section ◽  
Zr Alloy

A Cu-0.87%Cr-0.06%Zr alloy was subjected to equal channel angular pressing (ECAP) at a temperature of 400 °C up to a total strain of ~ 12. This processing produced ultra-fine grained (UFG) structure with an average grain size of 0.6 μm and an average dislocation density of ~4×1014 m-2. Tensile tests were carried out in the temperature interval 450 – 650 °C at strain rates ranging from 2.8´10-4 to 0.55 s-1. The alloy exhibits superplastic behavior in the temperature interval 550 – 600 °C at strain rate over 5.5´10-3 s-1. The highest elongation-to-failure of ~300% was obtained at a temperature of 575 °C and a strain rate of 2.8´10-3 s-1 with the corresponding strain rate sensitivity of 0.32. It was shown the superplastic flow at the optimum conditions leads to limited grain growth in the gauge section. The grain size increases from 0.6 μm to 0.87 μm after testing, while dislocation density decreases insignificantly to ~1014 m-2.

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