Design of face-shell bedded hollow masonry subject to concentrated loads

1996 ◽  
Vol 23 (1) ◽  
pp. 98-106 ◽  
Author(s):  
Ezzeldin Y. Sayed-Ahmed ◽  
Nigel G. Shrive
Keyword(s):  
Finite Element ◽  
Load Capacity ◽  
Three Dimensional ◽  
Element Model ◽  
Concentrated Loads ◽  
Concentrated Load ◽  
Strength Enhancement ◽  
Design Detail ◽  
Current Design ◽  
The Face

Many parameters affect the behaviour and failure of face-shell bedded hollow masonry subject to concentrated load. Detailed study of these parameters is needed to develop realistic design rules for this situation. The effects of loaded length and wall dimensions on capacity of the face-shell bedded hollow masonry subject to concentrated load are studied; the effect of mortar joint strength is also evaluated. The current design detail of filling some of the blocks under the concentrated load with grout is reviewed. The study was performed with a nonlinear elastoplastic finite element model that takes into account geometric and material nonlinearities as well as damage due to progressive cracking. The methodology, when combined with substructuring, allows analysis of substantially larger walls than would more typical three-dimensional analyses. The results indicate that the length of the loading plate is the significant parameter for load capacity. A possible design equation for plain hollow masonry subject to concentrated loads, concentric across the width of the wall, is provided. Adjustments could be made given the precise loading detail specified. Improvement details are explained. Key words: masonry, hollow concrete masonry, finite element modelling, cracking, failure, strength-enhancement factor, concentrated loads.

Numerical analysis of face-shell bedded hollow masonry walls subject to concentrated loads

1995 ◽  
Vol 22 (4) ◽  
pp. 802-818 ◽  
Author(s):  
Ezzeldin Y. Sayed-Ahmed ◽  
Nigel G. Shrive
Keyword(s):  
Finite Element ◽  
Rational Design ◽  
Element Model ◽  
Masonry Walls ◽  
Concentrated Loads ◽  
Concentrated Load ◽  
Finite Element Program ◽  
Strength Enhancement ◽  
Element Program ◽  
Iterative Procedures

A nonlinear elastoplastic finite element model has been developed for face-shell bedded hollow masonry walls subject to in-plane concentrated loads. The model takes into account geometric and material nonlinearities as well as damage due to progressive cracking. Behaviour of the masonry components subject to compressive states of stress is modelled using the theory of plasticity, and cracking is modelled using both discrete and smeared cracking approaches. The model is generated on a SUN SPARC 10/31 workstation using the preprocessor of the finite element program ANSYS; the finite element solution is obtained using the ABAQUS program on the Fujitsu VPX 240/10 and IBM RS/6000 workstation. A brief summary of the numerical modelling and the iterative procedures is discussed. Results from simulated tests of seven-course high wallettes subject to concentrated loads are used to verify the behaviour of the numerical analyses. The methodology, when combined with substructuring, allows analysis of substantially larger walls than would more typical 3-D analyses. The model can be used to check existing design rules and develop more rational design methods for hollow masonry subject to concentrated load. Key words: masonry, hollow concrete masonry, finite element modelling, cracking, failure, strength enhancement factor, concentrated loads.

Finite element buckling analysis of laminated composite sandwich panels with transversely flexible core carrying attached elastic strip

2012 ◽  
Vol 14 (6) ◽  
pp. 715-733
Author(s):  
Karamat Malekzadeh Fard ◽  
Alireza Sayyidmousavi ◽  
Zouheir Fawaz ◽  
Habiba Bougherara
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Sandwich Panels ◽  
Element Model ◽  
Attached Mass ◽  
Element Analysis ◽  
The Core ◽  
The Face

In this article, a three-dimensional finite element model is proposed to study the effect of distributed attached mass with thickness and stiffness on the buckling instability of sandwich panels with transversely flexible cores. Unlike the previous works in the literature which have made use of unified displacement theories, the present model uses different types of finite elements to model the core and the face sheets. It utilizes shell elements for the face sheets and three-dimensional solid elements for the core which enables the model to account for the transverse flexibility of the structure. The motions of the face sheets and the core as well as the attached mass are related through defining constraint equations between the nodes of their respective finite elements based on the concept of master and slave nodes which is incorporated into the finite element analysis program ANSYS through a user-defined subroutine. The validated finite element model is then used to study the effects of size, thickness, material property, aspect ratio, and the position of the attached mass on the buckling load of a sandwich panel under different combinations of boundary conditions. The results presented in this study have hitherto not been reported in the literature.

The Static Performance Analysis of Air Foil Journal Bearings Considering Three-Dimensional Structure of Bump Foil

2005 ◽  
Author(s):  
Dong-Hyun Lee ◽  
Young-Cheol Kim ◽  
Kyung-Woong Kim
Keyword(s):  
Finite Element ◽  
Load Capacity ◽  
Three Dimensional ◽  
Element Model ◽  
Journal Bearings ◽  
Dimensional Structure ◽  
Suggested Model ◽  
3 Dimensional ◽  
Foil Bearings ◽  
Static Performance

The calculation of bump foil deflection is very important to predict the performance of foil bearings more accurately, because the foil bearings consist of top foil and its elastic foundation usually called bump foil. For the purpose of this, a finite element model considering 3-dimensional structure of the bump foil is developed to calculate the deflection of inter-connected bump. The results obtained from the suggested model are compared and analyzed with those from the previous proposed deflection models. In addition, load capacity of the foil bearings is analyzed by using this model.

Development and Validation of a Three-Dimensional Finite Element Model of the Face

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
G. G. Barbarino ◽  
M. Jabareen ◽  
J. Trzewik ◽  
A. Nkengne ◽  
G. Stamatas ◽  
...  
Keyword(s):  
Finite Element ◽  
Magnetic Resonance ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Magnetic Resonance Images ◽  
Dimensional Finite Element ◽  
The Face ◽  
Three Dimensional Finite Element ◽  
Tissue Aging

A detailed three-dimensional finite element model of the face is presented in this paper. Bones, muscles, skin, fat, and superficial muscoloaponeurotic system were reconstructed from magnetic resonance images and modeled according to anatomical, plastic, and reconstructive surgery literature. The finite element mesh, composed of hexahedron elements, was generated through a semi-automatic procedure with an effective compromise between the detailed representation of anatomical parts and the limitation of the computational time. Nonlinear constitutive equations are implemented in the finite element model. The corresponding model parameters were selected according to previous work with mechanical measurements on soft facial tissue, or based on reasonable assumptions. Model assumptions concerning tissue geometry, interactions, mechanical properties, and the boundary conditions were validated through comparison with experiments. The calculated response of facial tissues to gravity loads, to the application of a pressure inside the oral cavity and to the application of an imposed displacement was shown to be in good agreement with the data from corresponding magnetic resonance images and holographic measurements. As a first application, gravimetric soft tissue descent was calculated from the long time action of gravity on the face in the erect position, with tissue aging leading to a loss of stiffness. Aging predictions are compared with the observations from an “aging database” with frontal photos of volunteers at different age ranges (i.e., 20–40 years and 50–70 years).

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

scholarly journals Comparison of Tooth- and Bone-Borne Appliances on the Stress Distributions and Displacement Patterns in the Facial Skeleton in Surgically Assisted Rapid Maxillary Expansion—A Finite Element Analysis (FEA) Study

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1152
Author(s):  
Rafał Nowak ◽  
Anna Olejnik ◽  
Hanna Gerber ◽  
Roman Frątczak ◽  
Ewa Zawiślak
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Rapid Maxillary Expansion ◽  
Stress Distributions ◽  
Maxillary Expansion ◽  
Facial Skeleton ◽  
Element Analysis ◽  
Maxillary Constriction

The aim of this study was to compare the reduced stresses according to Huber’s hypothesis and the displacement pattern in the region of the facial skeleton using a tooth- or bone-borne appliance in surgically assisted rapid maxillary expansion (SARME). In the current literature, the lack of updated reports about biomechanical effects in bone-borne appliances used in SARME is noticeable. Finite element analysis (FEA) was used for this study. Six facial skeleton models were created, five with various variants of osteotomy and one without osteotomy. Two different appliances for maxillary expansion were used for each model. The three-dimensional (3D) model of the facial skeleton was created on the basis of spiral computed tomography (CT) scans of a 32-year-old patient with maxillary constriction. The finite element model was built using ANSYS 15.0 software, in which the computations were carried out. Stress distributions and displacement values along the 3D axes were found for each osteotomy variant with the expansion of the tooth- and the bone-borne devices at a level of 0.5 mm. The investigation showed that in the case of a full osteotomy of the maxilla, as described by Bell and Epker in 1976, the method of fixing the appliance for maxillary expansion had no impact on the distribution of the reduced stresses according to Huber’s hypothesis in the facial skeleton. In the case of the bone-borne appliance, the load on the teeth, which may lead to periodontal and orthodontic complications, was eliminated. In the case of a full osteotomy of the maxilla, displacements in the buccolingual direction for all the variables of the bone-borne appliance were slightly bigger than for the tooth-borne appliance.

Reduction of Free-Edge Stress Concentration

1985 ◽  
Vol 52 (4) ◽  
pp. 801-805 ◽  
Author(s):  
P. R. Heyliger ◽  
J. N. Reddy
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Free Edge ◽  
Shear Stresses ◽  
Normal Stresses ◽  
Interlaminar Shear ◽  
Three Dimensional Elasticity

A quasi-three dimensional elasticity formulation and associated finite element model for the stress analysis of symmetric laminates with free-edge cap reinforcement are described. Numerical results are presented to show the effect of the reinforcement on the reduction of free-edge stresses. It is observed that the interlaminar normal stresses are reduced considerably more than the interlaminar shear stresses due to the free-edge reinforcement.

Progressive failure analysis of scarf-repaired composite laminate based on damage constitutive model

2016 ◽  
Vol 233 (2) ◽  
pp. 180-188 ◽  
Author(s):  
Qiuyi Shen ◽  
Zhenghao Zhu ◽  
Yi Liu
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Composite Laminate ◽  
Damage Mechanics ◽  
Cohesive Zone Model ◽  
Load Capacity ◽  
Three Dimensional ◽  
Zone Model ◽  
State Variables ◽  
Element Analysis

A three-dimensional finite element model for scarf-repaired composite laminate was established on continuum damage model to predict the load capacity under tensile loading. The mixed-mode cohesive zone model was adopted to the debonding behavior analysis of adhesive. Damage condition and failure of laminates and adhesive were subsequently addressed. A three-dimensional bilinear constitutive model was developed for composite materials based on damage mechanics and applied to damage evolution and loading capacity analyses by quantifying damage level through damage state variables. The numerical analyses were implemented with ABAQUS finite element analysis by coding the constitutive model into material subroutine VUMAT. Good agreement between the numerical and experimental results shows the accuracy and adaptability of the model.

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