scholarly journals Experimental and numerical analysis of deformation patterns in notched heterogeneous welds

2017 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Marc Giménez Avalos ◽  
Florence Keppens ◽  
Sameera Naib ◽  
Wim De Waele ◽  
Stijn Hertelé

Standardized weld flaw assessment techniques assume the weld region to be homogeneous which is a strong idealisation of reality. Characterising the effects of heterogeneous properties of welds through the analysis of deformation patterns and slip lines is the major concern of this research. It is the goal to investigate which effects these variations in properties within the weld material have on the propagation of cracks within the weld material. Performed experiments are SENT tests on strongly heterogeneous welded connections. The same material is also simulated with a weld heterogenisation model in ABAQUS®. Results from both experiments and simulations are discussed and compared. It is shown that slip lines tend to avoid zones of high hardness in a way that a path of least resistance is found. Related to this, it is seen that the slip line angles deviate from the theoretical 45° for homogeneous material. Obtained results validate the numerical model used.

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
J. M. Fernández Oro ◽  
J. González ◽  
R. Barrio Perotti ◽  
M. Galdo Vega

In this paper, a deterministic stress decomposition is applied over the numerical three-dimensional flow solution available for a single volute centrifugal pump. The numerical model has proven in previous publications its robustness to obtain the impeller to volute-tongue flow interaction, and it is now used as starting point for the current research. The main objective has been oriented toward a detailed analysis of the lack of uniformity in the flow that the volute tongue promotes on the blade-to-blade axisymmetric pattern. Through this analysis, the fluctuation field may be retrieved and main interaction sources have been pinpointed. The results obtained with the deterministic analysis become of paramount interest to understand the different flow features found in a typical centrifugal pump as a function of the flow rate. Moreover, this postprocessing tool provides an economic and easy procedure for designers to compare the different deterministic terms, also giving relevant information on the unresolved turbulence intensity scales. Complementarily, a way to model the turbulent effects in a systematic way is also presented, comparing their impact on the performance with respect to deterministic sources in a useful framework, that may be applied for similar kinds of pumps.


2010 ◽  
Vol 3 (3) ◽  
pp. 346-356 ◽  
Author(s):  
G. Savaris ◽  
P. H. Hallak ◽  
P. C. A. Maia

The objective of this article is to present the results obtained in a study on the interaction between the behavior of the structure and the foundation settlements and verify the influence of normal load distribution on the columns. In this mechanism, known as structure soil interaction (SSI), as the building is constructed, a transfer of loads occurs from the columns which tend to settle more to those that tend to settle less. The study was conducted in a building which had its settlements monitored from the beginning of construction. For this purpose, a linear tridimensional numerical model was constructed and numerical analysis was performed, using the finite elements method. In these analyses, numerical models corre- sponding to the execution of each floor were used, considering the settlements measured in each stage of the construction. The results of analy- ses showed that the effect of SSI are significant for calculating the normal efforts on the columns, particularly on those located in the first floors.


2020 ◽  
Vol 31 (13) ◽  
pp. 1617-1637
Author(s):  
Mohammad Naghavi Zadeh ◽  
Iman Dayyani ◽  
Mehdi Yasaee

A novel cellular mechanical metamaterial called Fish Cells that exhibits zero Poisson’s ratio in both orthogonal in-plane directions is proposed. Homogenization study on the Fish Cells tessellation is conducted and substantially zero Poisson’s ratio behavior in a homogenized tessellation is shown by numerical analysis. Experimental investigations are performed to validate the zero Poisson’s ratio feature of the metamaterial and obtain force–displacement response of the metamaterial in elastic and plastic zone. A detailed discussion about the effect of the numerical model approach and joints on the structural response of the metamaterial is presented. Morphing skin is a potential application for Fish Cells metamaterial because of the integration benefits of zero Poisson’s ratio design. The structural integrity of the Fish Cells is investigated by studying the stiffness augmentation under tension and in presence of constraints on transverse edges. Finally, geometrical enhancements for improved integrity of the Fish Cells are presented that result in substantially zero stiffness augmentation required for morphing skins.


Author(s):  
Michael Brünig ◽  
Marco Schmidt ◽  
Steffen Gerke

Abstract The paper deals with a numerical model to investigate the influence of stress state on damage and failure in the ductile steel X5CrNi18-10. The numerical analysis is based on an anisotropic continuum damage model taking into account yield and damage criteria as well as evolution equations for plastic and damage strain rate tensors. Results of numerical simulations of biaxial experiments with the X0- and the H-specimen presented. In the experiments, formation of strain fields are monitored by digital image correlation which can be compared with numerically predicted ones to validate the numerical model. Based on the numerical analysis the strain and stress quantities in selected parts of the specimens are predicted. Analysis of damage strain variables enables prediction of fracture lines observed in the tests. Stress measures are used to explain different stress-state-dependent damage and failure mechanisms on the micro-level visualized on fracture surfaces by scanning electron microscopy.


2019 ◽  
Vol 137 ◽  
pp. 01004
Author(s):  
Sebastian Werle ◽  
Szymon Sobek ◽  
Zuzanna Kaczor ◽  
Łukasz Ziółkowski ◽  
Zbigniew Buliński ◽  
...  

Paper present the experimental and numerical analysis of biomass photopyrolysis process. The experimental tests is performed on the solar pyrolysis installation, designed in Institute of Thermal Technology, Gliwice. It consist of the copper reactor powered by artificial light simulating sun. The paper shows the result of the solar pyrolysis of wood. The yield of the main fraction as a function of the process temperature is presented. Additionally the gas composition is determined. The numerical model is prepared in the Ansys Fluent 18.2 software, which allow at the same time for capturing geometry of the real system and easy change of input data. The results indicate that both the product yields (liquid, solid and gaseous) and gas components shares are strongly influenced by pyrolysis parameters and feedstock composition.


2019 ◽  
Vol 9 (20) ◽  
pp. 4289 ◽  
Author(s):  
Sangki Park

In South Korea, the construction of new multi-unit residential structures has been continuously increasing in order to accommodate multiple households in single structures. However, the presence of walls and floors shared with neighbors makes these structures exceptionally vulnerable to floor noise transmission when the noise of everyday life occurs. In particular, South Korea has many social problems associated with such floor noise, which require the utmost attention and immediate resolution. In this study, a 17-story structure was selected as a test structure. Field measurements were carried out. A numerical model for the 17-story structure was developed in order to perform a vibro-acoustic analysis. The validation of the numerical model comparing with the field measurement data results shows a good agreement. Finally, it is concluded that numerical analysis can be applied to resolve floor noise problems arising in multi-unit residential structures.


2012 ◽  
Vol 166-169 ◽  
pp. 720-724
Author(s):  
Bai Sheng Wang ◽  
Dong Hui Cao ◽  
Ying Wu Yang ◽  
Chun Xiao Xu ◽  
Hua Jun Qian

A space numerical model about 1000MW turbo generator foundation of a power plant is established by ANSYS software, meanwhile analyzing the model’s vibration characteristics and response under the turbo generator working conditions. According to the existing norms, optimizing the foundation based on the linear displacement amplitude control, furthermore researching the corresponding dynamic on the optimized foundation for guidance to structural design.


2012 ◽  
Vol 166-169 ◽  
pp. 2658-2662
Author(s):  
Xin Chen

Component removal method is usually taken to open up relief channel. It is necessary to make a research on the feasibility of removing and make an analysis on some problems. This paper summarized the typical collapsed buildings and the typical rescue technique used in Wenchuan earthquake. The numerical model of typical buildings collapsed was gotten . Based on the characteristics of the application of removing technique, a numerical analysis was made. The results show that the angle between the component and ground should not be changed. The direction in which the components are lifted should be in a moderate direction with other lap components .Try best to make its contact area produce some friction force.


2013 ◽  
Vol 339 ◽  
pp. 628-631
Author(s):  
Jian Zhang ◽  
Wen Xian Tang ◽  
Wen Long Qin ◽  
Chao Gao

Quasi-static numerical model of jack-up spudcan penetration in layered sandy soil was presented in this paper, based on explicit procedure. Three different methods, such as Lagrangian analysis, Lagrangian analysis with distortion control and Lagrangian-Eulerian analysis, were used to control soil negative element volumes or other excessive distortion. The results showed that, reasonable and stable numerical results could be solved by Lagrangian-Eulerian analysis. The magnitude of plastic strain, however, decreases at first and then increases to the maximum.


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