scholarly journals Three-Dimensional Probabilistic Analysis of The Surface Settlement Based On Spatial Variability of Soil Properties: Case Study Zarbalizadeh NATM Tunnel

2021 ◽  
Author(s):  
Mohammad Ali Tahmasebi ◽  
Reza Shirinabadi ◽  
Esmaiel Rahimi ◽  
Ehsan Moosavi ◽  
Amir Hossein Bangian Tabrizi
Keyword(s):  
Spatial Variability ◽  
Young’S Modulus ◽  
Urban Areas ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Mean Value ◽  
Surface Settlement ◽  
Effective Control ◽  
Allowable Limit ◽  
Natm Tunnel

Abstract Designing and the construction of a tunnel in urban areas has their own specific considerations. Usually, excessive settlement caused by tunneling during construction damages the adjacent infrastructures and utilities, especially if the tunnel is excavated by the new Austrian tunneling method (NATM). Thus, it’s important to make accurate predictions and effective control on tunneling-induced settlement. In this study, the soil’s Young’s modulus was modeled using a three-dimensional random field and coupled with a finite difference method (FDM) analysis to reveal the influence of scale of fluctuation (SOF) on the maximum surface settlement (Smax). To generate the field of soil’s Young’s modulus, the Fourier series method is employed and sensitivity studies are further performed via Monte-Carlo simulations (MCS). The results demonstrate both the mean value of Smax and its coefficient of variation (COV) increase from 28 mm to 31 mm and from 0.02 to 0.35 respectively, with an increasing horizontal SOF but they stabilize at higher values of SOF. Furthermore, the probability of failure increases as COV increases for each allowable limit greater than the verification FDM of Smax. It is observed that ignoring the spatial variability of soil’s properties leads to an underestimate of the risk of excessive surface settlement.

FEM Stress Analysis and Strength of Scarf Adhesive Joints of Similar Adherend Subjected to Impact Tensile Loadings

2007 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Yuya Hirayama ◽  
He Dan
Keyword(s):  
Young’S Modulus ◽  
Principal Stress ◽  
Stress Wave ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Maximum Principal Stress ◽  
Adhesive Joints ◽  
Stress Wave Propagation ◽  
Adhesive Thickness ◽  
Three Dimensional Finite Element

The stress wave propagation and stress distribution in scarf adhesive joints have been analyzed using three-dimensional finite element method (FEM). The FEM code employed was LS-DYNA. An impact tensile loading was applied to the joint by dropping a weight. The effect of the scarf angle, Young’s modulus of the adhesive and adhesive thickness on the stress wave propagations and stress distributions at the interfaces have been examined. As the results, it was found that the point where the maximum principal stress becomes maximum changes between 52 degree and 60 degree under impact tensile loadings. The maximum value of the maximum principal stress increases as scarf angle decreases, Young’s modulus of the adhesive increases and adhesive thickness increases. In addition, Experiments to measure the strains and joint strengths were compared with the calculated results. The calculated results were in fairly good agreements with the experimental results.

Coating agent-induced mechanical behavior of 3D self-assembled nanocrystals

2017 ◽  
Vol 19 (35) ◽  
pp. 23887-23897 ◽  
Author(s):  
Arzu Çolak ◽  
Jingjing Wei ◽  
Imad Arfaoui ◽  
Marie-Paule Pileni
Keyword(s):  
Mechanical Behavior ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Coating Agent ◽  
Self Assembled

The Young's modulus of three-dimensional self-assembled Ag nanocrystals, as so-called supracrystals, is correlated with the type of coating agent as well as the nanocrystal morphology.

scholarly journals Three-dimensional seismic analysis of concrete gravity dams considering foundation flexibility

2021 ◽  
Vol 25 (1) ◽  
pp. 88-98
Author(s):  
Mokhtar Messaad ◽  
Messoud Bourezane ◽  
Mohamed Latrache ◽  
Amina Tahar Berrabah ◽  
Djamel Ouzendja
Keyword(s):  
Young’S Modulus ◽  
Seismic Analysis ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Shear Stresses ◽  
Total System ◽  
Dam Reservoir ◽  
Principal Stresses ◽  
Foundation Soil ◽  
North West

Abstract Concrete dams are considered as complex construction systems that play a major role in the context of both economic and strategic utilities. Taking into account reservoir and foundation presence in modeling the dam-reservoir-foundation interaction phenomenon leads to a more realistic evaluation of the total system behavior. The article discusses the dynamic behavior of dam-reservoir-foundation system under seismic loading using Ansys finite element code. Oued Fodda concrete dam, situated at Chlef, in North-West of Algeria, was chosen as a case study. Parametric study was also performed for different ratios between foundation Young's modulus and dam Young's modulus E f /E d (which varies from 0.5 to 4). Added mass approach was used to model the fluid reservoir. The obtained results indicate that when dam Young's modulus and foundation Young's modulus are equal, the foundation soil leads to less displacements in the dam body and decreases the principal stresses as well as shear stresses.

Effective properties of composite materials containing voids

1993 ◽  
Vol 440 (1909) ◽  
pp. 461-473 ◽  
Keyword(s):  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Effective Properties ◽  
Young's Modulus ◽  
Matrix Material ◽  
Practical Importance ◽  
Three Dimensional ◽  
Poisson's Ratio ◽  
Two Dimensional ◽  
Isotropic Composite

Recent results of theoretical and practical importance prove that the two-dimensional (in-plane) effective (average) Young’s modulus for an isotropic elastic material containing voids is independent of the Poisson’s ratio of the matrix material. This result is true regardless of the shape and morphology of the voids so long as isotropy is maintained. The present work uses this proof to obtain explicit analytical forms for the effective Young’s modulus property, forms which simplify greatly because of this characteristic. In some cases, the optimal morphology for the voids can be identified, giving the shapes of the voids, at fixed volume, that maximize the effective Young’s modulus in the two-dimensional situation. Recognizing that two-dimensional isotropy is a subset of three-dimensional transversely isotropic media, it is shown in this more general case that three of the five properties are independent of Poisson’s ratio, leaving only two that depend upon it. For three-dimensionally isotropic composite media containing voids, it is shown that a somewhat comparable situation exists whereby the three-dimensional Young’s modulus is insensitive to variations in Poisson’s ratio, v m , over the range 0 ≤ v m ≤ ½, although the same is not true for negative values of v m . This further extends the practical usefulness of the two-dimensional result to three-dimensional conditions for realistic values of v m .

scholarly journals Influence of three-dimensional nanoparticle branching on the Young’s modulus of nanocomposites: Effect of interface orientation

2015 ◽  
Vol 112 (21) ◽  
pp. 6533-6538 ◽  
Author(s):  
Shilpa N. Raja ◽  
Andrew C. K. Olson ◽  
Aditya Limaye ◽  
Kari Thorkelsson ◽  
Andrew Luong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Elastic Stiffness ◽  
Limited Attention ◽  
Unexpected Finding ◽  
Covalent Bonds ◽  
Lattice Spring Model ◽  
Common Block

With the availability of nanoparticles with controlled size and shape, there has been renewed interest in the mechanical properties of polymer/nanoparticle blends. Despite the large number of theoretical studies, the effect of branching for nanofillers tens of nanometers in size on the elastic stiffness of these composite materials has received limited attention. Here, we examine the Young's modulus of nanocomposites based on a common block copolymer (BCP) blended with linear nanorods and nanoscale tetrapod Quantum Dots (tQDs), in electrospun fibers and thin films. We use a phenomenological lattice spring model (LSM) as a guide in understanding the changes in the Young's modulus of such composites as a function of filler shape. Reasonable agreement is achieved between the LSM and the experimental results for both nanoparticle shapes—with only a few key physical assumptions in both films and fibers—providing insight into the design of new nanocomposites and assisting in the development of a qualitative mechanistic understanding of their properties. The tQDs impart the greatest improvements, enhancing the Young's modulus by a factor of 2.5 at 20 wt.%. This is 1.5 times higher than identical composites containing nanorods. An unexpected finding from the simulations is that both the orientation of the nanoscale filler and the orientation of X-type covalent bonds at the nanoparticle-ligand interface are important for optimizing the mechanical properties of the nanocomposites. The tQD provides an orientational optimization of the interfacial and filler bonds arising from its three-dimensional branched shape unseen before in nanocomposites with inorganic nanofillers.

Influence of Mechanical Properties of Adhesives on Stress Distributions in Lap Joints

Volume 1 ◽  
2004 ◽  
Author(s):  
Xiaocong He ◽  
S. Olutunde Oyadiji
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Lap Joints ◽  
Stress Distributions ◽  
Element Analysis ◽  
Linear Elastic ◽  
Cantilevered Beam ◽  
Cantilevered Beams ◽  
Different Characteristics

This paper deals with stress analysis of a single lap-jointed cantilevered beam using the three dimensional linear elastic finite element analysis (FEA) technique. Numerical examples are provided to show the influence on the stresses of the single lap-jointed cantilevered beams using adhesives of different characteristics which encompass the entire spectrum of viscoelastic behaviour. The results indicate that the stress distributions of a single-lap jointed cantilevered beam are strongly affected by both Young’s modulus and Poisson’s ratios. The maximum stress ratio was used to determine maximum values of Young’s Modulus required in order that the static stresses of an adhesively bonded cantilevered beam will not be more than given value of that of the equivalent homogeneous structure, that is a geometrically similar beam but without a joint. The analysis results also show that by choosing suitable adhesives, the maximum stresses can be reduced and the strength can be improved.

scholarly journals Alleviating Distortion and Improving the Young’s Modulus in Two-Photon Polymerization Fabrications

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 615 ◽  
Author(s):  
Chow-Shing Shin ◽  
Tzu-Jui Li ◽  
Chih-Lang Lin
Keyword(s):  
Young’S Modulus ◽  
Structural Integrity ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Three Dimensional Printing ◽  
Two Photon ◽  
Laser Focus ◽  
Micro Cantilever ◽  
Micro Structures ◽  
Two Photon Polymerization

Two-photon polymerization enables the extremely high resolution three-dimensional printing of micro-structures. To know the mechanical properties, and better still, to be able to adjust them is of paramount importance to ensuring the proper structural integrity of the printed products. In this work, the Young’s modulus is measured on two-photon polymerized micro-cantilever bars. Optimizing the scanning trajectory of the laser focus points is important in alleviating distortion of the printed bars. By increasing the laser power and decreasing the inter-voxel distances we can double the Young’s modulus. Post-curing with ultraviolet light can approximately quadruple the Young’s modulus. However, the resulting modulus is still only about 0.3% of that of the bulk polymerized material.

Three-Dimensional Finite Element Stress Response Analysis of Laminated Cantilever Beams With Adhesive Layers Subjected to Impact Loadings

1999 ◽  
Author(s):  
Jyo Shimura ◽  
Izumi Higuchi ◽  
Toshiyuki Sawa
Keyword(s):  
Young’S Modulus ◽  
Principal Stress ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Maximum Principal Stress ◽  
Stress Wave Propagation ◽  
Adhesive Interface ◽  
Number Of Layers ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Abstract The stress behavior in adhesive laminated cantilever beams subjected to impact loadings is analyzed using three-dimensional finite-element method (FEM) in the elastic region. The stress wave propagation and the stress distribution at the interfaces are examined. The effects of Young’s modulus of adherends, adhesive, the adherend thickness and the number of layers on the stress wave propagation at the interfaces are clarified. The following results are obtained. The maximum principal stress (σ1) is maximal at the adhesive interfaces. It is found that the maximum principal stress (σ1) at the adhesive interface increases as the Young’s modulus of the upper adherends increases. The maximum principal stress (σ1) at the adhesive interface increases as Young’s modulus of the adhesive increases. The maximum principal stress (σ1) at the adhesive interface decreases as the thickness of the adherend to which an impact load is applied increases. It is seen that the maximum principal stress (σ1) increases as number of layers increases. Experiments were carried out to measure the strain response of adhesive laminated cantilever beam using strain gauges. A fairly good agreement is seen between the analytical and experimental results.

Design Method for Inner Structure of Injection Mold Fabricated by Metal Laser Sintering

2012 ◽  
Vol 6 (5) ◽  
pp. 584-590 ◽  
Author(s):  
Hiroshi Koresawa ◽  
◽  
Hirofumi Fukumaru ◽  
Michio Kojima ◽  
Jun Iwanaga ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Design Method ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Optimization Method ◽  
Laser Sintering ◽  
Sintered Body ◽  
Sintering Process

This paper discusses design methods for the internal structure of molds used in production utilizing metal laser sintering combined with high speedmilling which selectively sinters metal powder to form a three dimensional mold. This milling technique is characterized by the fact that the selective laser sintering process and milling process are carried out in alternating sequence, achieving the level of processing accuracy demanded of mold production. In addition, in the selective laser sintering process, because the mechanical strength of the sintered body (Young’s Modulus) is variable, suitable interior structures that consider dynamic conditions are expected. However, in the current state of design, this structure is determined experimentally, and there is a high possibility of incurring unnecessary production time and high costs. In this paper, we investigate a method that incorporates an optimization method using stress that occurs within the structure interior, obtains the interior topological structure as a Young’s Modulus distribution, and designs a suitable interior structure using this distribution. As a result of investigation using numerical analysis, we obtained a structure that reduces the volume of the sintered body, having high mechanical strength in comparison with a conventional structure while improving structural rigidity.

scholarly journals Three-dimensional microstructure and numerical calculation of elastic properties of alpine snow with a focus on weak layers

2014 ◽  
Vol 60 (222) ◽  
pp. 705-713 ◽  
Author(s):  
Berna Köchle ◽  
Martin Schneebeli
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Large Change ◽  
X Ray ◽  
Weak Layer ◽  
Snow Stratigraphy ◽  
Precise Characterization ◽  
Microstructural Variability

AbstractThe microstructure and stratigraphy of a snowpack determine its physical behaviour. Weak layers or weak interfaces buried under a slab are prerequisites for the formation of dry-snow slab avalanches, and a precise characterization of weak layers or interfaces is essential to assess stability. Yet their exact geometry and micromechanical properties are poorly known. We cast weak layers and their adjacent layers in the field during two winters and reconstructed their three-dimensional microstructure using X-ray microcomputer tomography. The high resolution of 10–20 μm allowed us to study snow stratigraphy at the microstructural scale. We quantified the microstructural variability for 32 centimetre-sized layered samples and we calculated Young’s modulus and Poisson’s ratio by tomography-based finite-element simulations. Layers in a sample could therefore be differentiated not only by a change in morphology or microstructure, but also by a change in mechanical properties. We found a logarithmic correlation of Young’s modulus with density for two different density ranges, consistent with previous studies. By calculating the relative microstructural changes within our samples, we showed that a large change could indicate a potential weak layer, but only when the weak layer and both adjacent layers, i.e. the sandwich, were considered.

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