Numerical Study of the Impact of Constitutive Modelling on the Evolution of Necking in the Case of a Tensile Test on C68 Grade Steel

2014 ◽  
Vol 611-612 ◽  
pp. 521-528 ◽  
Author(s):  
Laurent Tabourot ◽  
Pascale Balland ◽  
Ndéye Awa Sene ◽  
Mathieu Vautrot ◽  
Nesrine Ksiksi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Tensile Test ◽  
Numerical Study ◽  
Constitutive Modelling ◽  
Microscopic Level ◽  
Point Of View ◽  
Physical Phenomena ◽  
The Impact ◽  
Over Time ◽  
Grade Steel

This article deals with numerical simulation of necking. It draws the attention onto the importance of the description of strain-hardening and the effects on the evolution of necking. In order to compare necking evolution in relation with different plasticity models, a tracking procedure which consists in determining the evolution over time of discharged volumes of the sample is adopted. Models that take into account physical phenomena at the microscopic level and especially the heterogeneities of materials from a mechanical point of view seem well suited to fit experimental evidence connected to necking.

scholarly journals Breccia interlayer effects on steam-assisted gravity drainage performance: experimental and numerical study

2021 ◽  
Author(s):  
Qichen Zhang ◽  
Xiaodong Kang ◽  
Huiqing Liu ◽  
Xiaohu Dong ◽  
Jian Wang
Keyword(s):  
Numerical Simulation ◽  
Oil Recovery ◽  
Oil Sands ◽  
Numerical Study ◽  
Middle Part ◽  
Experimental Results ◽  
Production Performance ◽  
Peak Oil ◽  
Steam Chamber ◽  
The Impact

AbstractCurrently, the reservoir heterogeneity is a serious challenge for developing oil sands with SAGD method. Nexen’s Long Lake SAGD project reported that breccia interlayer was widely distributed in lower and middle part of reservoir, impeding the steam chamber expansion and heated oil drainage. In this paper, two physical experiments were conducted to study the impact of breccia interlayer on development of steam chamber and production performance. Then, a laboratory scale numerical simulation model was established and a history match was conducted based on the 3D experimental results. Finally, the sensitivity analysis of thickness and permeability of breccia layer was performed. The influence mechanism of breccia layer on SAGD performance was analyzed by comparing the temperature profile of steam chamber and production dynamics. The experimental results indicate that the existence of breccia interlayer causes a thinner steam chamber profile and longer time to reach the peak oil rate. And, the ultimate oil recovery reduced 15.8% due to much oil stuck in breccia interlayer areas. The numerical simulation results show that a lower permeability in breccia layer area has a serious adverse impact on oil recovery if the thickness of breccia layer is larger, whereas the effect of permeability on SAGD performance is limited when the breccia layer is thinner. Besides, a thicker breccia layer can increase the time required to reach the peak oil rate, but has a little impact on the ultimate oil recovery.

Numerical Study of Phase Change Influence on Wave Impact Loads in LNG Tanks on Floating Structures

2018 ◽  
Author(s):  
Matthieu Ancellin ◽  
Laurent Brosset ◽  
Jean-Michel Ghidaglia
Keyword(s):  
Natural Gas ◽  
Phase Change ◽  
Numerical Study ◽  
Model Tests ◽  
Impact Loads ◽  
Wave Impact ◽  
Floating Structures ◽  
Physical Phenomena ◽  
The Impact ◽  
Phase Phase

Understanding the physics of sloshing wave impacts is necessary for the improvement of sloshing assessment methodology based on sloshing model tests, for LNG membrane tanks on floating structures. The phase change between natural gas and liquefied natural gas is one of the physical phenomena involved during a LNG wave impact but is not taken into account during sloshing model tests. In this paper, some recent numerical and analytical works on the influence of phase change are summarized and discussed. For the impact of an ideally shaped wave, phase change influences two different steps of the impact in different ways: during the gas escape phase, phase change leads to a higher impact velocity; for entrapped gas pockets, phase change causes a reduction of the pressure in the gas pocket. However, this influence is quantitatively small. The generalization to more realistic wave shapes (including e.g. liquid aeration) should be the focus of future works.

Numerical Simulation of a Dilute Particulate Flow (Laminar) Over Tube Banks

1994 ◽  
Vol 116 (4) ◽  
pp. 770-777 ◽  
Author(s):  
Yong-Du Jun ◽  
Widen Tabakoff
Keyword(s):  
Numerical Simulation ◽  
Impact Angle ◽  
Protective Role ◽  
Point Of View ◽  
Particulate Flow ◽  
Tube Bank ◽  
Semiempirical Equation ◽  
Tube Banks ◽  
Bank System ◽  
The Impact

This paper presents an investigation of numerical simulation for a dilute particle laden flow (laminar) over in-line tube banks. Particles behavior of two different sizes and density (100 μm sand and 40 μm fly ash) is demonstrated through the present study for a fixed geometry and flow condition, that is, a square in-line tube bank of two rows deep with pitch-to-diameter ratio of two at Reynolds number 400. Dilute particulate flow assumption is used and the drag force is considered as the only external force term that affects the particles behavior in the flow. Experimental rebounding data and semiempirical equation for the erosion estimation are used. It was found through the present simulation that the particles behavior of the different sizes and density in tube bank system is quite different in their trajectories, impact and the erosion pattern. The protective role of the first row of cylinders could be supported with respect to the particles collision on the cylinder but not necessarily to the erosion point of view. Also the information at impact such as the impact velocity and the impact angle which affect the erosion (Tabakoff et al., 1988) can be estimated by using the numerical simulation shown in the present study.

Simulation of collisions between two identical meteoroid fragments arranged one behind the other

2019 ◽  
Author(s):  
V.T. Lukashenko ◽  
F.A. Maksimov
Keyword(s):  
Inelastic Collision ◽  
Numerical Study ◽  
Small Deviation ◽  
Simulation Method ◽  
The Other ◽  
Recovery Coefficient ◽  
Small Oscillations ◽  
Inelastic Impact ◽  
The Impact ◽  
Over Time

To calculate the dynamics of a system of meteoroid fragments, a simulation method has been developed with an algorithm for calculating collisions between individual bodies. The algorithm for calculating collisions allows one to simulate absolutely elastic, inelastic and absolutely inelastic impacts between individual bodies with the help of a given coefficient of the impact recovery. The impact recovery coefficient can be set separately for each collision based on the known characteristics of the colliding bodies. We carried out a numerical study of the problem of collisions between identical meteoroid fragments initially located one behind the other along the direction of motion. The study shows that bodies will periodically collide in the case of absolutely elastic impact; there is an equilibrium maximum distance between the bodies to which the system will evolve. In the case of an inelastic impact, the distance between the bodies decreases over time; the configuration evolves to the joint flight of the bodies located one right after another. The problem of an absolutely inelastic collision between the identical bodies located within a small initial distance and with a small deviation in position of the backward body shows that the location of the bodies directly behind each other is unstable to small oscillations and is not implemented numerically at large times.

Estimation of Mechanical Properties of Al/Cu Compound Layer Formed by Impact Welding

2005 ◽  
Vol 502 ◽  
pp. 455-460 ◽  
Author(s):  
Hidefumi Date ◽  
Masatoshi Futakawa ◽  
Masaaki Naka
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Tensile Test ◽  
Strain Curve ◽  
Fem Analysis ◽  
Compound Layer ◽  
Joint Interface ◽  
Material Constants ◽  
Impact Welding ◽  
The Impact

The impact welding of aluminum onto copper was carried out using a gas gun and the mechanical properties of Al/Cu joint were investigated by tensile tests and micro hardness indentation tests. The strength measured by tensile test decreased with increasing of the impact velocity. The results of the tensile test suggested that it was necessary to make a microscopic survey of the joint interface. Then, the inverse analysis with FEM analysis was applied to the load and depth curves measured by the indentation technique to identify the material constants in the constitutive equations of aluminum, copper and the compound layer. In addition, the numerical simulation for the tensile test was carried out using the identified material constants of aluminum, copper and the compound layer. The nominal stress-strain curve of the compound layer obtained by the numerical simulation showed the typical feature of brittle material. The ultimate tensile stress of the compound layer was about 1.2 GPa and ten times larger than that of aluminum. It was concluded that the bonding strength of Al/Cu joint was dependent on the integrity of the compound layer.

scholarly journals A numerical study to improve the position and angle of the producer gas injector inside the intake manifold to minimize emissions and efficiency enhancement of a bi engine

2021 ◽  
pp. 100-109
Author(s):  
Hussein A. Mahmood ◽  
Ali O. Al-Sulttani ◽  
Osam H. Attia ◽  
Nor Mariah. Adam
Keyword(s):  
Numerical Simulation ◽  
Numerical Study ◽  
Single Point ◽  
Flow Characteristics ◽  
Engine Performance ◽  
Simulation Software ◽  
Petrol Engine ◽  
Intake Manifold ◽  
Producer Gas ◽  
The Impact

To develop a petrol engine so that it works under the bi-engine pattern (producer gas-petrol) without any additional engine modifications, a single-point injection method inside the intake manifold is a simple and inexpensive method. Still, it leads to poor mixing performance between the air and producer gas. This deficiency can cause unsatisfactory engine performance and high exhaust emissions. In order to improve the mixing inside the intake manifold, nine separate cases were modelled to evaluate the impact of the position and angle orientation inside the intake manifold on the uniformity and spread of the mixture under AFR=2.07. A petrol engine (1.6 L), the maximum engine speed (8000 rpm), and bi-engine mode (petrol-producer gas engine). The employ of the numerical simulation software (ANSYS workbench 19), the propagation, flow characteristics, and uniformity of the blend within the nine different cases were evaluated. According to the outcomes of the numerical simulation, it was found that creating vortices and turbulent flow for the producer gas and air inside the intake manifold is the perfect method to obtain a uniformity mixture of air and producer gas inside the intake manifold. In addition, extending the blending duration allows air and producer gas fuel to be mixed efficiently. Furthermore, the greatest uniformity and the maximum spread rate at the outlet of manifold are obtained in cases 1, 4, and 7, when the producer gas injector location is constant (P1, P2 or P3). In addition, the weakest spread of producer gas at the outlet of the manifold is observed in case 9 in comparison with the other cases. Moreover, it is observed that case (1) generated the maximum uniformity index (UI) level

scholarly journals Blockchain application in the distribution chain of the COVID-19 vaccine: a designing understudy

2020 ◽  
Author(s):  
Leonardo Juan Ramirez Lopez ◽  
Nicolas Beltrán Álvarez
Keyword(s):  
Supply Chain ◽  
Critical Points ◽  
Point Of View ◽  
Effective Vaccine ◽  
Research Centers ◽  
The World ◽  
Distribution Chain ◽  
The Impact ◽  
Over Time

<p>The impact of COVID-19 has challenged science in its quest to control and mitigate it through a new vaccine. This is why the world's research centers and laboratories are in serious competition over time to offer humanity an effective vaccine that prevents the spread of this virus. From a technological point of view, the challenge is to manage the distribution of this next vaccine, from its generation anywhere in the world, to the site of application to the population. The research results approximate the solution to the design of a secure Blockchain-based supply chain surveillance design, to control the variables and critical points of the next distribution of vaccines worldwide. The expected impact of the application of this new design will be the confidence of the population in the quality of the vaccine, in the generating laboratory, and it supplies.</p>

A Numerical Study on Change in the Marine Environment of Tokyo Bay in the Latest 70 Years

2003 ◽  
Author(s):  
Daisuke Kitazawa ◽  
Masataka Fujino ◽  
Shigeru Tabeta
Keyword(s):  
Numerical Simulation ◽  
Marine Environment ◽  
Field Data ◽  
Numerical Study ◽  
Marine Ecosystem ◽  
Oxygen Demand ◽  
Ecosystem Model ◽  
Tokyo Bay ◽  
Marine Ecosystem Model ◽  
The Impact

A numerical study by means of a marine ecosystem model is conducted to examine the causes of change in the marine environment of Tokyo Bay in the latest 70 years. First, the marine ecosystem model is validated by comparing the predicted water quality such as water temperature, dissolved oxygen (DO), chemical oxygen demand (COD), total phosphorus (T-P) and total nitrogen (T-N) for the year of 1994 with the field data, which has been observed at 48 spots in Tokyo Bay. In addition, topography of Tokyo Bay and the discharge of chemical matters from the rivers are estimated for each year of 1935, 1979, and 1994, and the marine environment in the summer of each year is reproduced by numerical simulation. From comparing the results, it is revealed that the marine environment varies corresponding mainly to change in the discharge of chemical matters, and that the impact of reclamation is about 30% of the impact of change in the discharge of chemical matters.

The impact of acquisitions on inventory performance

2017 ◽  
Vol 14 (3) ◽  
pp. 288-312 ◽  
Author(s):  
Ari-Pekka Hameri ◽  
Lawrence A. Weiss
Keyword(s):  
Inventory Management ◽  
Past Research ◽  
Point Of View ◽  
Limited Attention ◽  
Inventory Level ◽  
Content Type ◽  
Acquisition Period ◽  
The Impact ◽  
The Relationship ◽  
Over Time

Purpose The purpose of this paper is to examine the relationship between acquisitions and inventory performance. Specifically, it analyzes the inventory performance (inventory level) of acquirers and their targets pre- and post-acquisition. Design/methodology/approach Using several business databases, a sample of 270 horizontal acquisitions by US firms between 1996 and 2004 is subject to multivariate analysis. Various robustness tests are applied to validate the results. Findings Three main results are found. First, the acquirer’s inventory performance is normally better than its target’s prior to the acquisition, consistent with acquirers taking over less efficient firms rather than cherry picking the more efficient ones. Second, inventory performance improves over time in the post-acquisition period in those cases where the acquirer is more efficient than the target. Third, inventory performance deteriorates over time in the post-acquisition period in those cases where the acquirer is less efficient than the target. The results are consistent with acquisitions being associated with both efficiency gains and efficiency losses due to (in)efficiency transfers from acquirers to targets. Practical implications From the management point of view, the study delivers the strongest message to companies that have substantial inventories and for whom efficient inventory management is vital to overall performance. Managers who are unaware of the potential consequences of acquisitions on inventory performance destroy value. Originality/value This research complements past research by showing that in spite of their synergetic potential, reducing inventory receives only limited attention in acquisitions.

Interpreting the New Testament as a Sacred Text

2021 ◽  
pp. 233-250
Author(s):  
Donald Senior
Keyword(s):  
New Testament ◽  
Point Of View ◽  
Biblical Text ◽  
Sacred Text ◽  
Christian Life ◽  
Christian Community ◽  
Modern Methods ◽  
The New Testament ◽  
The Impact ◽  
Over Time

While a convincing case can be made about the sacredness of the New Testament through its proclamation of Jesus Christ and its guidance on the nature of Christian life, this does not mean that over time, or at any particular time, all Christians understand the message of the Scriptures in the same way. This brings us to the question of “interpretation” of the New Testament. How do we accurately understand the message of a particular New Testament book? How would we describe the meaning of the New Testament for Christian life today? How do we understand, from a doctrinal point of view, the identity of Jesus portrayed in the ensemble of the New Testament writings? What do we understand to be the defining characteristics and structures of the Christian community derived from the diverse books of the New Testament? Additionally, who has the authority to determine what is an authentic or valid answer to such questions? And what are the proper methods of extracting contemporary meaning from these ancient texts? This chapter traces in broad strokes the diverse ways the Christian community has approached the meaning of the New Testament over the centuries, with particular attention to the impact of modern methods of interpreting the biblical text.

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