Analysis of load in ties in masonry veneer walls

2003 ◽  
Vol 30 (5) ◽  
pp. 850-860 ◽  
Author(s):  
Junyi Yi ◽  
David Laird ◽  
Bill McEwen ◽  
Nigel G Shrive

Masonry is frequently used as a veneer, tied to a backup structural system. In many cases, the structural system is steel studding. Very little research has been conducted to examine the effect of staggering the ties between the veneer and the backup on the load distributions in the ties and studs. This paper describes three-dimensional (3-D) finite element models developed for masonry veneer walls (brick veneer – steel stud) subjected to wind load. Various tie arrangements were analyzed. Shell elements were used to model the brick veneer, and beam elements were used to model the steel studs and ties. Cracking was introduced in a horizontal mortar joint through the use of gap elements (discrete cracking method). The loads in the ties for various tie arrangements were examined. It appears that staggering the ties does not overload them when a full row of ties is provided at the top or at both the top and the bottom. The load distribution in the ties in a staggered arrangement is close to that in the full-tie arrangement.Key words: masonry veneer walls, 3-D, finite element models, brick veneer, steel studs, ties.

Author(s):  
Yifan Zhu ◽  
Chaoran Xu ◽  
Chung C. Fu

A curved and/or skewed steel I-girder bridge, in addition to the basic vertical shear and bending effects, will be subjected to torsional and warping effects. Thus, simplified hand calculation and line girder methods, might not be enough when bridges are to be analyzed. Refined methods, termed by AASHTO, have to be adopted. This paper has investigated the closeness and difference between curved bridge finite element models using 2-D gird and 3-D shell elements of I-girders, both are part of AASHTO refined method. Moreover, the results are calibrated by comparing analysis result with various two-dimensional and three-dimensional computations with varied curvature effects. It is concluded that when introducing torsional effects to finite element models, the modified torsional constant J with consideration of warping effect should be taken into the 2-D grid model as a refined model. When using 3-D shell elements as the refined model, stiffeners and connection plates play an important role of global model stiffness and should not be ignored, especially for sharp curved steel I-girder bridges.


Author(s):  
P J Prendergast ◽  
S J Toland ◽  
J P Corrigan

Experimental and theoretical stress analysis methods are used to evaluate the mechanical behaviour of external fixation devices as load-bearing structures. For the experimental part, a modular assembly was fabricated from which unilateral and bilateral fixators of different design configurations were assembled and tested under various loading conditions. A reflective photoelasticity technique was used to study the effect of frame configuration on the stress patterns generated around the pin-bone interface. Finite element models of each design were also generated using three-dimensional beam and shell elements. Spring elements were used to model the pin/sidebar clamp. It is shown that close correspondence between the experimental and theoretical methods of investigation is obtained when the flexibility of the pin/side-bar clamp is taken into account. It is also shown that a unilateral design, modified by attaching a second side-bar to the first and connecting them by means of a semicircular component, can achieve some of the structural advantages of bilateral fixators without the clinical disadvantage of transfixing pins.


2021 ◽  
Vol 11 (19) ◽  
pp. 9024
Author(s):  
Fiammetta Venuti ◽  
Marco Domaneschi ◽  
Marc Lizana ◽  
Branko Glisic

Modern footbridges are often lively structures, characterized by natural frequencies that fall in the range of pedestrian activities, such as walking, running, and jumping. Therefore, serviceability assessment under human-induced excitation is crucial both at the design stage and during the footbridge lifetime. This paper presents and validates two different FE models of an existing footbridge with very complex geometry: the Streicker Footbridge at the Princeton University Campus. It represents a benchmark in the field as a testbed for vibration serviceability assessments under pedestrian excitation. The real structure is equipped with strain and temperature sensors that are currently used to collect measurements in both static and dynamic modes for research and educational purposes in Structural Health Monitoring (SHM). Based on detailed drawings of the Streicker Footbridge, a three-dimensional beam-based model was developed to represent the complex behavior of the full-scale benchmark bridge. Subsequently, a more refined discretization of the bridge deck adopting shell elements was inserted. The bridge Finite Element models were validated against available SHM data concerning static and dynamic tests. The relevant ANSYS APDL script files along with an example of pedestrian jumping application are available upon request for further research developments on the relationship between pedestrians and the benchmark footbridge.


2013 ◽  
Vol 554-557 ◽  
pp. 484-491 ◽  
Author(s):  
Alexander S. Petrov ◽  
James A. Sherwood ◽  
Konstantine A. Fetfatsidis ◽  
Cynthia J. Mitchell

A hybrid finite element discrete mesoscopic approach is used to model the forming of composite parts using a unidirectional glass prepreg non-crimp fabric (NCF). The tensile behavior of the fabric is represented using 1-D beam elements, and the shearing behavior is captured using 2-D shell elements into an ABAQUS/Explicit finite element model via a user-defined material subroutine. The forming of a hemisphere is simulated using a finite element model of the fabric, and the results are compared to a thermostamped part as a demonstration of the capabilities of the used methodology. Forming simulations using a double-dome geometry, which has been used in an international benchmarking program, were then performed with the validated finite element model to explore the ability of the unidirectional fabric to accommodate the presence of interlaminate cabling.


Author(s):  
A Meghdari ◽  
R Davoodi ◽  
F Mesbah

This paper presents an engineering analysis of shoulder dystocia (SD) in the human birth process which usually results in damaging the brachial plexus nerves and the humerus and/or clavicle bones of the baby. The goal is to study these injuries from the mechanical engineering point of view. Two separate finite element models of the neonatal neck and the clavicle bone have been simulated using eight-node three-dimensional elements and beam elements respectively. Simulated models have been analysed under suitable boundary conditions using the ‘SAP80’ finite element package. Finally, results obtained have been verified by comparing them with published clinical and experimental observations.


1996 ◽  
Vol 118 (4) ◽  
pp. 399-406 ◽  
Author(s):  
W. J. Koves ◽  
S. Nair

A specialized shell-intersection finite element, which is compatible with adjoining shell elements, has been developed and has the capability of physically representing the complex three-dimensional geometry and stress state at shell intersections (Koves, 1993). The element geometry is a contoured shape that matches a wide variety of practical nozzle configurations used in ASME Code pressure vessel construction, and allows computational rigor. A closed-form theory of elasticity solution was used to compute the stress state and strain energy in the element. The concept of an energy-equivalent nodal displacement and force vector set was then developed to allow complete compatibility with adjoining shell elements and retain the analytical rigor within the element. This methodology provides a powerful and robust computation scheme that maintains the computational efficiency of shell element solutions. The shell-intersection element was then applied to the cylinder-sphere and cylinder-cylinder intersection problems.


1996 ◽  
Vol 11 (4) ◽  
pp. 371-380 ◽  
Author(s):  
Alphose Zingoni

Where a finite element possesses symmetry properties, derivation of fundamental element matrices can be achieved more efficiently by decomposing the general displacement field into subspaces of the symmetry group describing the configuration of the element. In this paper, the procedure is illustrated by reference to the simple truss and beam elements, whose well-known consistent-mass matrices are obtained via the proposed method. However, the procedure is applicable to all one-, two- and three-dimensional finite elements, as long as the shape and node configuration of the element can be described by a specific symmetry group.


Author(s):  
Hossam S. Badawi ◽  
Sherif A. Mourad ◽  
Sayed M. Metwalli

Abstract For a Computer Aided Design of a concrete truck mixer, a six cubic meter concrete mixer drum is analyzed using the finite element method. The complex mixer drum structure is subjected to pressure loading resulting from the plain concrete inside the drum, in addition to its own weight. The effect of deceleration of the vehicle and the rotational motion of the drum on the reactions and stresses are also considered. Equivalent static loads are used to represent the dynamic loading effects. Three-dimensional shell elements are used to model the drum, and frame elements are used to represent a ring stiffener around the shell. Membrane forces and bending stresses are obtained for different loading conditions. Results are also compared with approximate analysis. The CAD procedure directly used the available drafting and the results were used effectively in the design of the concrete mixer drum.


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