Structural Design of the Geometrical Shape of Interfaces in Bonded Dissimilar Materials Based on Theoretical Elastic Analysis

1999 ◽  
Vol 586 ◽  
Author(s):  
Masayoshi Tateno ◽  
Yasushi Fukuzawa ◽  
Shigeru Nagasawa ◽  
Hiroshi Sakuta
Keyword(s):  
Stress Distribution ◽  
Structural Design ◽  
Bonding Strength ◽  
Stress Singularity ◽  
Dissimilar Materials ◽  
Correlation Factor ◽  
Geometrical Shape ◽  
Elastoplastic Behavior ◽  
Secant Stiffness ◽  
The Relationship

ABSTRACTIn order to evaluate the practical strength of a joint and its fracture mode, it is important to find the stress distribution near the edge of the interface by analyses of strength and fracture. The index of stress singularity based on theoretical analysis is a useful tool to indicate the stress distribution.In this paper, investigations on the evaluation of the practical strength of bonded dissimilar materials based on the stress singularity are carried out. The secant stiffness module, which was used for plastics analysis, was applied to the evaluation of thermal elastoplastic behavior near the interface. Spherical conditions of the interface shape were used for the evaluation of stress behavior and the experiment of bonding strength. The relationship between the index of stress singularity, λ, and the practical strength of the bonded TiB2-Ni system was investigated by comparing theoretical λ, which was determined by substituting the secant stiffness module into Bogy's eigenequation, with the practical strength in the edge angle of the interface between 60° and 90° The correlation factor of the relationship between λ and the practical bonding strength of the TiB2-Ni system was found positive. These results show that the structural design of a geometrical interface which is getting a higher strength joint based on the index of stress singularity is verified experimentally.

The Effects of Materials Properties & Angle Junction on Stress Concentration at Interface of Dissimilar Materials

2011 ◽  
Vol 383-390 ◽  
pp. 887-892
Author(s):  
Alireza Fallahi Arezoodar ◽  
Ali Baladi
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Stress Reduction ◽  
Stiffness Matrix ◽  
Stress Singularity ◽  
Dissimilar Materials ◽  
Element Analysis ◽  
Materials Properties ◽  
Main Factors ◽  
Elastic Modules

In dissimilar material joints, failure often occurs along the interface between two materials due to stress singularity. Stress distribution and its concentration depend on materials and geometry of the junction as the stress concentration depends on grain orientation and its stiffness matrix of neighboring grains in micro-scale. Inhomogenity of stress distribution at the interface of junction of two materials with different elastic modules and stress concentration in this zone are the main factors resulting in rupture of the junction. Effect of materials properties, thickness, and joining angle at the interface of aluminum-polycarbonate will be discussed in this paper. Computer simulation and finite element analysis by ABAQUS showed that convex interfacial joint leads to stress reduction at junction corners in compare with straight joint. This finding is confirmed by photoelastic experimental results.

Relation between Stress Intensity Factor of a Small Edge Interface Crack and Intensity of Free-Edge Stress Singularity of Bonded Dissimilar Materials

2004 ◽  
Vol 261-263 ◽  
pp. 351-356
Author(s):  
Seiji Ioka ◽  
Shiro Kubo
Keyword(s):  
Stress Intensity Factor ◽  
Free Surface ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Edge Crack ◽  
Stress Singularity ◽  
Dissimilar Materials ◽  
Free Edge ◽  
Edge Stress ◽  
The Relationship

When two materials are bonded, the free-edge stress singularity usually develops near the intersection of the interface and the free-surface. Fracture in bonded dissimilar materials may therefore occur from an interface crack which develops at the intersection of interface and free-surface. Free-edge stress singularity is very important in the evaluation of strength of bonded dissimilar materials. In this study, the relationship between the stress intensity factor of a small edge crack on interface of bonded dissimilar materials and the intensity of free-edge stress singularity of bonded dissimilar materials with no crack under external mechanical loading was investigated numerically by using the boundary element method. The relationship was also investigated theoretically by using the principle of superposition. The results of numerical analyses were compared with those of theoretical analyses. It was found that stress intensity factors of small edge crack on interface K1 and K2 were proportional to the intensity of free-edge stress singularity of bonded dissimilar materials Kσ without crack irrespective of the combination of materials. The numerically determined proportional coefficient between K1 and Kσ agreed well with the theoretical one, and was not affected by crack length when proper normalizations were applied. From these results, it is suggested that stress intensity factor of small edge crack on interface can be used as a strength criterion of interface of bonded dissimilar materials.

Relationship Between Singularity Strength Factors and Practical Bonding Strength of Ceramic to Metal Joint

2010 ◽  
Author(s):  
Masayoshi Tateno ◽  
Hiroki Morikawa
Keyword(s):  
Stress Intensity ◽  
Bonding Strength ◽  
Wedge Angle ◽  
Stress Singularity ◽  
Interface Shape ◽  
Intensity Factors ◽  
Electric Discharge Machining ◽  
Metal Joint ◽  
The Relationship ◽  
Interface Geometry

This study correlates the stress intensity factors (Kii, Kpaii), the order of the stress singularity p-1, and the practical bonding strength of ceramic to metal joints with arbitrary interface geometry. First, in order to describe the stress behavior of TiB2 to Ni joints bonded at 1173K, the stress singularity factors (Kii, Kpaii, p-1) were theoretically derived for wedge angles of φ1:30°<φ1<150°. Secondly, the dependences of the singularity factors on the wedge angle φ1 were compared with experimental results using the same wedge angles on TiB2 to Ni joints with interface convexity or concavity produced by Electric Discharge Machining (EDM). In order to obtain the highest strength joints, the optimum interface shape is determined using the relationship between the singularity factors.

scholarly journals Convenient Evaluation Method for Bonding Strength of Dissimilar Materials with Index of Stress Singularity.

1994 ◽  
Vol 60 (577) ◽  
pp. 1920-1926 ◽  
Author(s):  
Masayoshi Tateno ◽  
Yasushi Fukuzawa ◽  
Shigeru Nagasawa ◽  
Harumichi Takahashi ◽  
Hiroshi Sakuta ◽  
...  
Keyword(s):  
Bonding Strength ◽  
Evaluation Method ◽  
Stress Singularity ◽  
Dissimilar Materials

Characteristics of Stress Distribution of Micro-Cantilever of Polycrystalline Copper at the Pull-in Voltage

2013 ◽  
Vol 300-301 ◽  
pp. 1309-1312
Author(s):  
Ji Long Su ◽  
Yan Jiao Zhang ◽  
Xing Feng Lian
Keyword(s):  
Stress Distribution ◽  
Cantilever Beam ◽  
Electrostatic Force ◽  
Polycrystalline Copper ◽  
Maximum Deflection ◽  
Micro Cantilever ◽  
Fixed End ◽  
The Relationship

The Ansys simulate software is utilized to analyze pull-in voltages and stresses of the fixed end of micro- cantilever beam with different thicknesses respectively. Based on the analysis of the electrostatic force at the pull-in voltage, the stress of fixed end of micro-beam and the maximum deflection are obtained. The relationship between the stress of fixed end and thickness is established. The results show that the mutation thickness of the stress and the pull-in voltage are at and respectively , it is consistent with the intrinsic size of the polycrystalline copper micro-beam.

scholarly journals A Non-Singular Analytical Technique for Reinforced Non-Circular Holes in Orthotropic Laminate

2020 ◽  
Vol 25 (1) ◽  
pp. 92-105
Author(s):  
Pradeep Mohan ◽  
R. Ramesh Kumar
Keyword(s):  
Stress Distribution ◽  
Analytical Solution ◽  
Power Series ◽  
Orthotropic Shell ◽  
Infinite Plate ◽  
Stress Singularity ◽  
Power Series Solution ◽  
Element Analysis ◽  
Full Field ◽  
Analytical Technique

AbstractThe intricacy in Lekhnitskii’s available single power series solution for stress distribution around hole edge for both circular and noncircular holes represented by a hole shape parameter ε is decoupled by introducing a new technique. Unknown coefficients in the power series in ε are solved by an iterative technique. Full field stress distribution is obtained by following an available method on Fourier solution. The present analytical solution for reinforced square hole in an orthotropic infinite plate is derived by completely eliminating stress singularity that depends on the concept of stress ratio. The region of validity of the present analytical solution on reinforcement area is arrived at based on a comparison with the finite element analysis. The present study will also be useful for deriving analytical solution for orthotropic shell with reinforced noncircular holes.

scholarly journals Prediction of Inhomogeneous Stress in Metal Structures: A Hybrid Approach Combining Eddy Current Technique and Finite Element Method

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yating Yu ◽  
Fei Yuan ◽  
Hanchao Li ◽  
Cristian Ulianov ◽  
Guiyun Tian
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Magnetic Flux ◽  
Flux Density ◽  
Eddy Current ◽  
Magnetic Flux Density ◽  
Fe Method ◽  
Metal Structures ◽  
Current Technique ◽  
The Relationship

Concentrated stresses and residual ones are critical for the metal structures’ health, because they can cause microcracks that require emergency maintenance or can result in potential accidents. Therefore, an accurate approach to the measurement of stresses is key for ensuring the health of metal structures. The eddy current technique is an effective approach to detect the stress according to the piezoresistive effect. However, it is limited to detect the surface stress due to the skin effect. In engineering, the stress distribution is inhomogeneous; therefore, to predict the inhomogeneous stress distribution, this paper proposes a nondestructive approach which combines the eddy current technique and finite element (FE) method. The experimental data achieved through the eddy current technique determines the relationship between the applied force and the magnetic flux density, while numerical simulations through the FE method bridge the relationship between the magnetic flux density and the stress distribution in different directions. Therefore, we can predict the inhomogeneous stress nondestructively. As a case study, the applied stress in a three-point-bending simply supported beam was evaluated, and the relative error is less than 8% in the whole beam. This approach can be expected to predict the residual stress in metal structures, such as rail and vehicle structures, if the stress distribution pattern is known.

scholarly journals Évaluation de degré de défense de l’architecture défensive pré-coloniale en Algérie : cas des villages fortifiés

X ◽  
2020 ◽  
Author(s):  
Mohand Oulmas ◽  
Amina Abdessemed-Fouda ◽  
Ángel Benigno González Avilés
Keyword(s):  
Complex System ◽  
Cultural Values ◽  
Case Studies ◽  
Cultural Landscape ◽  
Geometrical Shape ◽  
Defense System ◽  
Medieval Period ◽  
Architectural Features ◽  
The Relationship

Assassing the defensibility of the pre-colonial defensive architecture in Algeria: case study on the medieval fortified villagesAlgeria’s pre-colonial towns of the medieval period still exist in different typologies, ranging from the isolated buildings (forts, castles) and town enclosures to whole urban units (fortified villages, defensives towns). Indeed, the constituent of these fortresses was their defense system, characterized by its large dimension, constituted essentially by the enclosure wall, and architectural features of defensiveness correlated with the outside and the inside of the fortresses. This paper aims to evaluate the relationship between physical landscape, built defensive features and cultural values of the medieval fortified villages in Algeria, two medieval fortified villages in our case “Kalaa of Beni Abbes” in Bejaia and “Kalaa of Beni Rached” in Oran, that we identified as an evolved landscape and interpreted as complex system (both defensive architecture and continuing cultural landscape). This current study consists of quantifying the defensiveness degree of these sites situated within different contexts, in fact, this method ensures to identify the strategy adopted to be protected against different invasions. However, in order to achieve this we calculate a spatial defensiveness index (DI) of these sites. The parameters of our choice are related to the implantation site, the elevation, the visibility and the geometrical shape, which allow us to estimate the defensiveness degree of the defense system of our case studies.

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