Assessment of the Realistic Stiffness and Capacity of the Connections in Quincha Frames to Develop Numerical Models

2013 ◽  
Vol 778 ◽  
pp. 526-533 ◽  
Author(s):  
Natalie Quinn ◽  
Dina D’Ayala
Keyword(s):  
Finite Element ◽  
Numerical Models ◽  
Experimental Tests ◽  
Element Model ◽  
Accurate Representation ◽  
Timber Frame ◽  
Historic Structures ◽  
The World ◽  
Infill Material ◽  
High Degree

Peru is one of the most seismically active countries in the world, this fact highlighted by several destructive earthquakes in recent years. The centre of Lima has a large number of historic structures with a ground floor in adobe, and their upper storeys in quincha, a traditional technique consisting of a timber frame with an infill of canes and mud. Despite the existence of a large number of buildings containing this technique, very little is known about its seismic performance. In order to investigate this, a series of experimental tests on quincha frames, with and without the infill, have been carried out previously, with the aim of quantifying the lateral behaviour and identifying vulnerable areas. The present paper details work carried out to develop a finite element model of the test frames without infill. This model of the timber frame will enable an accurate representation of the frame behaviour to be developed before adding the infill of canes and mud to the model. As the behaviour of the infill material and its connection to the frame is difficult to determine, characterising the timber frame with a high degree of accuracy ensures that the contribution of the infill can be globally quantified from the overall experimental results. The beams and posts are connected by cylindrical mortice and tenon joints, with a diagonal bracing member providing some lateral restraint. The connections have been modelled semi-rigid springs, with the stiffness calculated using variations of the component method. This was found to give very similar results to those obtained experimentally.

scholarly journals Numerical Simulation of Steel Reinforced Concrete (SRC) Joints

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 131 ◽  
Author(s):  
Isaac Montava ◽  
Ramon Irles ◽  
Jorge Segura ◽  
Jose Gadea ◽  
Ernesto Juliá
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Finite Element Model ◽  
Numerical Models ◽  
Experimental Tests ◽  
Element Model ◽  
Reinforced Concrete Beams ◽  
Plastic Behavior ◽  
Steel Reinforced Concrete ◽  
Concrete Joints

This paper presents a three-dimensional finite element model to confirm experimental tests carried out on steel reinforced concrete joints. The nonlinear behavior of this concrete is simulated, along with its reduced capability to resist large displacements in compression. The aim was to obtain the plastic behavior of reinforced concrete beams with a numerical model in the same way as obtained experimentally, in which the reduction of strength in the post-critical stage was considered to simulate behavior until structures collapsed. To do this, a nonlinear calculation was necessary to simulate the behavior of each material. Three numerical models provide a moment–curvature graph of the cross-section until collapse. Simulation of the structural elements is a powerful tool that avoids having to carry out expensive experimental tests. From the experimental results a finite element model is simulated for the non-linear analysis of steel reinforced concrete joints. It is possible to simulate the decreasing stress behavior of the concrete until reaching considerable displacement. A new procedure is discussed to capture the moment-curvature diagram. This diagram can be used in a simplified frame analysis, considering post-critical behavior for future research.

scholarly journals Comparison of different finite element model updates based on experimental onsite testing: the case study of San Giovanni in Macerata

2021 ◽  
Author(s):  
Carlo Baggio ◽  
Valerio Sabbatini ◽  
Silvia Santini ◽  
Claudio Sebastiani
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Numerical Models ◽  
Dynamic Properties ◽  
Structural Parameters ◽  
Element Model ◽  
Ambient Vibration ◽  
Geotechnical Investigations ◽  
Historic Structures

AbstractUnderstanding the behavior of historic structures that have undergone structural changes, restorations, and damage over time is still a significant challenge for structural engineers, particularly in those countries subject to high seismic risk, such as Italy. The study of built heritage for its prevention and conservation is an active research topic, due to the numerous uncertainties present in historic structures. Finite element modelling has become the most common and accessible method to study the behavior of complex masonry structures, however, the gap between numerical and experimental analysis may lead to erroneous results. Model updating techniques can reduce the discrepancy between the behavior of the numerical models and the testing results. The goal of this work is to illustrate a methodology to integrate the information derived from local, global, and geotechnical investigations into the finite element model of the masonry historical church of San Giovanni in Macerata, considering the Douglas–Reid model updating method. The PRiSMa laboratory of Roma Tre University carried out local investigations such as sonic tomography, video endoscopy and double flat jack tests, along with five ambient vibration tests that were processed through the operational modal analysis to extrapolate the dynamic properties of the building (modal frequency, modal shape vector and modal damping). The combined use of global, local and geotechnical information implemented in the methodology effectively reduced the uncertainties of the model and led the refinement and validation of the most relevant structural parameters.

scholarly journals Finite Element Modelling of a Parabolic Trough Collector for Concentrated Solar Power

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 209
Author(s):  
Andrea Gilioli ◽  
Francesco Cadini ◽  
Luca Abbiati ◽  
Giulio Angelo Guido Solero ◽  
Massimo Fossati ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Numerical Models ◽  
Local Strain ◽  
Experimental Tests ◽  
Element Model ◽  
Torsional Stiffness ◽  
Parabolic Trough ◽  
Global Parameter ◽  
Parabolic Trough Collector

Nowadays the design of large-scale structures can be effectively improved by the adoption of numerical models. Even if experimental tests still play a fundamental role, a methodological approach that combines experimental testing and modelling technique can significantly improve the understanding of the matter. This, in fact, would result in a more reliable optimization process, drastically reducing efforts and uncertainties towards the implementation of the final product. The present work deals with the development of a finite element model for the analysis of a full-scale prototype of an innovative parabolic trough collector. The collector is analysed under several load conditions in order to evaluate its structural behaviour. Each load configuration is also numerically reproduced. Moreover, it is demonstrated that the model is capable of reproducing both the global (stiffness) and local (strain state) behaviour of the structure. Specifically, the comparison between experimental data and numerical results show a good agreement for the global parameter torsional stiffness. Local strain values are also well reproduced in high-stressed zone. Thus, the model can be used as a reliable “virtual tool” for designers to evaluate the suitability of layout modifications, thereby replacing and reducing the amount of commonly needed experimental tests and, consequently, reducing time and costs. Finally, an example of the potentiality of the finite element model adopted for a computer-aided engineering approach is shown to determine the most promising solution for increasing the torsional stiffness of the trough, while simultaneously limiting the required experimental tests.

scholarly journals Possible reasons for early artificial bone failure in biomechanical tests of ankle arthrodesis systems

2015 ◽  
Vol 1 (1) ◽  
pp. 507-509
Author(s):  
H. Martin ◽  
N. Gutteck ◽  
J.-B. Matthies ◽  
T. Hanke ◽  
G. Gradl ◽  
...  
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Experimental Tests ◽  
Element Model ◽  
Ankle Arthrodesis ◽  
Artificial Bone ◽  
Basic Model ◽  
Simplified Finite Element Model ◽  
Biomechanical Tests ◽  
Horizontal Displacements

AbstractIn order to demonstrate the influence of the boundary conditions in experimental biomechanical investigations of arthrodesis implants two different models were investigated. As basic model, a simplified finite element model of the cortical bone was used in order to compare the stress values with (Model 1) and without (Model 2) allowing horizontal displacements of the load application point. The model without constraints of horizontal displacements showed considerably higher stress values at the point of failure. Moreover, this investigation shows that the boundary conditions (e.g. constraints) have to be carefully considered, since simplifications of the reality with experimental tests cannot always be avoided.

Rotordynamics Analysis: Experimental and Numerical Investigations

2003 ◽  
Author(s):  
Jean-Jacques Sinou ◽  
David Demailly ◽  
Cristiano Villa ◽  
Fabrice Thouverez ◽  
Michel Massenzio ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Critical Speed ◽  
Experimental Tests ◽  
Element Model ◽  
Test Rig ◽  
Turbofan Engine ◽  
Rotating Structure ◽  
Vibration Problems ◽  
The Finite Element Model

This paper presents a research devoted to the study of vibration problems in turbofan application. Several numerical and experimental tools have been developed. An experimental test rig that simulates the vibrational behavior of a turbofan engine is presented. Moreover, a finite element model is used in order to predict the non-linear dynamic behavior of rotating machines and to predict the first critical speed of engineering machine. A comparison between the experimental tests and the numerical model is conducted in order to evaluate the critical speed of the rotating structure and to update the finite element model.

scholarly journals Torsional Behaviour and Finite Element Analysis of the Hybrid Laminated Composite Shafts: Comparison of VARTM with Vacuum Bagging Manufacturing Method

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Mehmet Emin Taşdelen ◽  
Mehmet Halidun Keleştemur ◽  
Ercan Şevkat
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Glass Fibers ◽  
Laminated Composite ◽  
Experimental Tests ◽  
Element Model ◽  
Performance Criteria ◽  
Fiber Types ◽  
Element Analysis ◽  
Manufacturing Method

Braided sleeve composite shafts are produced and their torsional behavior is investigated. The braided sleeves are slid over an Al tube to create very strong and rigid tubular form shafts and they are in the form of 2/2 twill biaxial fiber fabric that has been woven into a continuous sleeve. Carbon and glass fibers braided sleeves are used for the fabrication of the composite shafts. VARTM (vacuum assisted resin transfer molding) and Vacuum Bagging are the two different types of manufacturing methods used in the study. Torsional behaviors of the shafts are investigated experimentally in terms of fabrication methods and various composite materials parameters such as fiber types, layer thickness, and ply angles. Comparing the two methods in terms of the torque forces and strain angles, the shafts producing entirely carbon fiber show the highest torque capacities; however, considering the cost and performance criteria, the hybrid shaft made up of carbon and glass fibers is the optimum solution for average demanded properties. Additionally, FE (finite element) model of the shafts was created and analyzed by using ANSYS workbench environment. Results of finite element analysis are compared with the values of twisting angle and torque obtained by experimental tests.

The effects of shape memory alloys’ tension–compression asymmetryon NiTi endodontic files’ fatigue life

2018 ◽  
Vol 232 (5) ◽  
pp. 437-445 ◽  
Author(s):  
MR Karamooz-Ravari ◽  
R Dehghani
Keyword(s):  
Finite Element ◽  
Shape Memory ◽  
Numerical Models ◽  
Equivalent Stress ◽  
Element Model ◽  
Niti Shape Memory Alloy ◽  
Element Analysis ◽  
Tension And Compression ◽  
Von Mises Equivalent Stress ◽  
Von Mises

Nowadays, NiTi rotary endodontic files are of great importance due to their flexibility which enables the device to cover all the portions of curved canal of tooth. Although this class of files are flexible, intracanal separation might happen during canal preparation due to bending or torsional loadings of the file. Since fabrication and characterization of such devices is challenging, time-consuming, and expensive, it is preferable to predict this failure before fabrication using numerical models. It is demonstrated that NiTi shape memory alloy shows asymmetric material response in tension and compression which can significantly affect the lifetime of the files fabricated from. In this article, the effects of this material asymmetry on the bending response of rotary files are assessed using finite element analysis. To do so, a constitutive model which takes material asymmetry into account is used in combination with the finite element model of a RaCe file. The results show that the material asymmetry can significantly affect the maximum von Mises equivalent stress as well as the force–displacement response of the tip of this file.

scholarly journals Displacement Study of a Large-Scale Freeform Timber Plate Structure Using a Total Station and a Terrestrial Laser Scanner

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 413 ◽  
Author(s):  
Anh Chi Nguyen ◽  
Yves Weinand
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Laser Scanner ◽  
Experimental Tests ◽  
Point Clouds ◽  
Element Model ◽  
Experimental Investigations ◽  
Bottom Surface ◽  
Terrestrial Laser Scanner ◽  
Total Station

Recent advances in timber construction have led to the realization of complex timber plate structures assembled with wood-wood connections. Although advanced numerical modelling tools have been developed to perform their structural analysis, limited experimental tests have been carried out on large-scale structures. However, experimental investigations remain necessary to better understand their mechanical behaviour and assess the numerical models developed. In this paper, static loading tests performed on timber plate shells of about 25 m span are reported. Displacements were measured at 16 target positions on the structure using a total station and on its entire bottom surface using a terrestrial laser scanner. Both methods were compared to each other and to a finite element model in which the semi-rigidity of the connections was represented by springs. Total station measurements provided more consistent results than point clouds, which nonetheless allowed the visualization of displacement fields. Results predicted by the model were found to be in good agreement with the measurements compared to a rigid model. The semi-rigid behaviour of the connections was therefore proven to be crucial to precisely predict the behaviour of the structure. Furthermore, large variations were observed between as-built and designed geometries due to the accumulation of fabrication and construction tolerances.

Fracture Evaluation of the Falling Weight Impact Behaviour of a Basalt/Vinylester Composite Plate through a Multiphase Finite Element Model

2017 ◽  
Vol 754 ◽  
pp. 59-62 ◽  
Author(s):  
Felipe Vannucchi de Camargo ◽  
Ana Pavlovic
Keyword(s):  
Finite Element ◽  
Natural Fibers ◽  
Fem Simulation ◽  
Experimental Tests ◽  
Element Model ◽  
Multiphase Model ◽  
Low Velocity ◽  
Weight Impact ◽  
The One ◽  
Falling Weight

Several investigations regarding the mechanical behaviour of composites reinforced by natural fibers under impact have been realized recently, aiming at achieve a low-weight and resistant design. At the same time, progressively accurate results on numerical simulations have been reached powered by modern Finite Element Method (FEM) approaches for composites; however, demonstrating a faithful indentation pattern is still a challenge. The present work aims at building an impact numerical simulation that exhibits a fracture mechanism exactly like the one seen in experimental tests, also carried in this work, on a Basalt Reinforced Composite Polymer (BRFP) plate subjected to low-velocity falling weight impact (IFW). The FEM simulation describes a multiphase model considering each ply and their inter-layer interactions.

scholarly journals Vibration-based Bayesian model updating of civil engineering structures applying Gaussian process metamodel

2019 ◽  
Vol 22 (16) ◽  
pp. 3487-3502
Author(s):  
Hossein Moravej ◽  
Tommy HT Chan ◽  
Khac-Duy Nguyen ◽  
Andre Jesus
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bayesian Approach ◽  
Model Updating ◽  
Numerical Models ◽  
Element Model ◽  
The Body ◽  
Structural Safety ◽  
Discrepancy Function ◽  
The Finite Element Model

Structural health monitoring plays a significant role in providing information regarding the performance of structures throughout their life spans. However, information that is directly extracted from monitored data is usually susceptible to uncertainties and not reliable enough to be used for structural investigations. Finite element model updating is an accredited framework that reliably identifies structural behavior. Recently, the modular Bayesian approach has emerged as a probabilistic technique in calibrating the finite element model of structures and comprehensively addressing uncertainties. However, few studies have investigated its performance on real structures. In this article, modular Bayesian approach is applied to calibrate the finite element model of a lab-scaled concrete box girder bridge. This study is the first to use the modular Bayesian approach to update the initial finite element model of a real structure for two states—undamaged and damaged conditions—in which the damaged state represents changes in structural parameters as a result of aging or overloading. The application of the modular Bayesian approach in the two states provides an opportunity to examine the performance of the approach with observed evidence. A discrepancy function is used to identify the deviation between the outputs of the experimental and numerical models. To alleviate computational burden, the numerical model and the model discrepancy function are replaced by Gaussian processes. Results indicate a significant reduction in the stiffness of concrete in the damaged state, which is identical to cracks observed on the body of the structure. The discrepancy function reaches satisfying ranges in both states, which implies that the properties of the structure are predicted accurately. Consequently, the proposed methodology contributes to a more reliable judgment about structural safety.

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