scholarly journals Out-of-plane local mechanism analysis with finite element method

2021 ◽  
Vol 8 (1) ◽  
pp. 130-136
Author(s):  
Roberto Spagnuolo
Keyword(s):  
Finite Element ◽  
Masonry Walls ◽  
Finite Element Models ◽  
Mechanism Analysis ◽  
Fem Method ◽  
Local Mechanism ◽  
Out Of Plane ◽  
Smeared Crack ◽  
The Stability ◽  
No Tension Material

Abstract The stability check of masonry structures is a debated problem in Italy that poses serious problems for its extensive use. Indeed, the danger of out of plane collapse of masonry walls, which is one of the more challenging to evaluate, is traditionally addressed not using finite element models (FEM). The power of FEM is not properly used and some simplified method are preferred. In this paper the use of the thrust surface is suggested. This concept allows to to evaluate the eccentricity of the membrane stresses using the FEM method. For this purpose a sophisticated, layered, finite element with a no-tension material is used. To model a no-tension material we used the smeared crack method as it is not mesh-dependent and it is well known since the early ’80 in an ASCE Report [1]. The described element has been implemented by the author in the program Nòlian by Softing.

Behaviour of hollow concrete masonry walls with one-course bond beams subjected to concentric and eccentric concentrated loading

2003 ◽  
Vol 30 (1) ◽  
pp. 181-190 ◽  
Author(s):  
Junyi Yi ◽  
Nigel G Shrive
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Three Dimensional ◽  
Masonry Walls ◽  
Finite Element Models ◽  
Concentrated Load ◽  
Concrete Masonry ◽  
Out Of Plane ◽  
Concentrated Loading ◽  
Concrete Masonry Walls

Three-dimensional finite element models of unreinforced hollow concrete masonry walls with one-course bond beams subjected to concentrated loading have been analyzed. The walls were modelled with different loading plate sizes, different loading locations along the wall (at the midpoint of the wall, at the end of the wall, and between these points), and different out-of-plane eccentricities (e = 0, t/6, and t/3). The hollow block units, mortar, grout, and bond beam blocks in the walls were modelled separately. Both smeared and discrete cracking methods have been utilized for predicting cracking under load. Geometric and material nonlinearities and damage due to progressive cracking were taken into account in the analyses. The predicted failure modes and ultimate capacities of the walls with the concentric concentrated load applied at the midpoint or at the end of the wall compared very well with the experimental results. When the load was between the midpoint and the end of the wall, the predicted ultimate capacity was between those for the load at the midpoint and at the end. The strength of the walls decreases with increasing out-of-plane eccentricities.Key words: finite element models, hollow masonry, smeared and discrete cracking models, concentrated load, loading locations, out-of-plane eccentricities.

scholarly journals Retrofitting Masonry Walls against Out-Of-Plane Loading with Timber Based Panels

2021 ◽  
Vol 11 (12) ◽  
pp. 5443
Author(s):  
Ornella Iuorio ◽  
Jamiu A. Dauda
Keyword(s):  
Finite Element ◽  
Peak Load ◽  
Small Scale ◽  
Masonry Walls ◽  
Finite Element Models ◽  
Three Phase ◽  
Out Of Plane ◽  
Low Performance ◽  
Type 3 ◽  
Compressive Damage

Unreinforced masonry walls are prone to failure when subjected to out-of-plane loading. This is due to their low performance in bending, and often the lack of appropriate connection to returning walls and floors. This paper investigates the possibility to use oriented strand boards (OSB) panels to improve the out-of-plane performance of brick masonry walls. The proposed technique considers securing OSB type-3 panels behind masonry walls with chemical and mechanical connections. The work presents finite element models to predict their behaviour. The models have been calibrated and validated through a three-phase experimental campaign, aimed at (a) characterizing the main structural components, (b) studying the out-of-plane behaviour of small-scale masonry prisms and (c) studying the behaviour of 1115 × 1115 × 215 mm masonry walls. The finite element models developed are based on a micromodel technique developed in ABAQUS and demonstrated to adequately capture the behaviour of both plain and retrofitted models to the ultimate load. The models also show an excellent correlation of the compressive damage and tensile damage with the experimental failure pattern. Generally, the model predicted the peak load and the corresponding failure and toughness to within less than 10% of the average test results.

Strains and Deflections of GFRP Sandwich Panels Due to Uniform Out-of-Plane Pressure

2002 ◽  
Vol 39 (04) ◽  
pp. 223-231
Author(s):  
J. C. Roberts ◽  
M. P. Boyle ◽  
P. D. Wienhold ◽  
E. E. Ward
Keyword(s):  
Finite Element ◽  
Compressive Strain ◽  
Sandwich Panels ◽  
External Pressure ◽  
Woven Fabric ◽  
Core Material ◽  
Finite Element Models ◽  
Strain Gages ◽  
Glass Fiber Reinforced Plastic ◽  
Out Of Plane

Rectangular orthotropic glass fiber reinforced plastic sandwich panels were tested under uniform out-of-plane pressure and the strains and deflections were compared with those from finite-element models of the panels. The panels, with 0.32 cm (0.125 in.) face sheets and a 1.27 cm (0.5 in.)core of either balsa or linear polyvinylchloride foam, were tested in two sizes: 183 × 92 cm (72 × 36 in.) and121 × 92 cm (48 × 36 in.). The sandwich panels were fabricated using the vacuum-assisted resin transfer molding technique. The two short edges of the sandwich panels were clamped, while the two long edges were simply supported. Uniform external pressure was applied using two large water inflatable bladders in series. The deflection and strains were measured using dial gages and strain gages placed at quarter and half points on the surface of the panels. Measurements were made up to a maximum out-of-plane pressure of 0.1 MPa (15psi). A total of six balsa core and six foam core panels were tested. Finite-element models were constructed for the 183-cm-long panel and the121-cm-long panel. Correlation between numerical and experimental strains to deflect the sandwich panel was much better on the top (tensile) side of the panels than on the bottom (compressive)side of the panels, regardless of panel aspect ratio or core material. All sandwich panels exhibited the same compressive strain reversal behavior on the compressive side of the panel. This phenomenon was thought to be due to nonlinearly induced micro-buckling under the strain gages, buckling of the woven fabric, or micro-cracking within the resin.

Forming limit diagrams by including the M–K model in finite element simulation considering the effect of bending

2016 ◽  
Vol 232 (8) ◽  
pp. 625-636 ◽  
Author(s):  
Mostafa Habibi ◽  
Ramin Hashemi ◽  
Ahmad Ghazanfari ◽  
Reza Naghdabadi ◽  
Ahmad Assempour
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Metal Forming ◽  
Forming Limit Diagram ◽  
Element Model ◽  
Forming Limit ◽  
Finite Element Models ◽  
Element Simulation ◽  
Simple Tension ◽  
Out Of Plane

Forming limit diagram is often used as a criterion to predict necking initiation in sheet metal forming processes. In this study, the forming limit diagram was obtained through the inclusion of the Marciniak–Kaczynski model in the Nakazima out-of-plane test finite element model and also a flat model. The effect of bending on the forming limit diagram was investigated numerically and experimentally. Data required for this simulation were determined through a simple tension test in three directions. After comparing the results of the flat and Nakazima finite element models with the experimental results, the forming limit diagram computed by the Nakazima finite element model was more convenient with less than 10% at the lower level of the experimental forming limit diagram.

scholarly journals A New Appliance for Improving the Miniscrew Stability

2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
Nurhat Ozkalayci ◽  
Mehmet Yetmez
Keyword(s):  
Finite Element ◽  
Stability Analysis ◽  
Primary Stability ◽  
Position Angle ◽  
Cortical Layer ◽  
Finite Element Models ◽  
Constant Force ◽  
The Stability

The aim of this study is to present a new appliance called stability leg designed as an additional anchorage providing device for increasing primary stability of orthodontic miniscrew. For this purpose, two finite element models (FEMs) with two different cortical layer thicknesses of 1 mm and 2 mm are considered. In order to achieve the stability analysis, these two main models, namely, Model I and Model II, are divided into subgroups according to stability leg lengths. Two types of forces are considered. (1) First force is a constant force of 1 N which is applied to all two models. (2) Second force is defined in the range of 1–4 N. Each of 1, 2.5, and 4 N of the second force is applied with a position angle ranging from 34° to 44°. Results show that stability of a miniscrew with 5 mm leg increases primary stability of the miniscrew.

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