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Numerical-Informational Methodology for Characterising Steel Bolted Components coupling Finite Element Simulations and Soft Computing Techniques
... There were examples of both identical and dissimilar T-stub configurations among the specimens. To determine the full force-displacement curve of bolted connections, Fernandez-Ceniceros [65][66][67] has conducted extensive studies. Precise estimation of link behavior was achieved using the hybridization of FE modeling with soft-computing approaches [68]. ...
This study presents finite element analysis of double split tee (DST) connections with high-strength steel bolts and coupled split tee sections, to evaluate various cyclic response parameters and elements. The investigation included quantifying connection behavior and hysteretic response, damage indexes, and failure modes. Over 40 specimens were simulated in ABAQUS under cyclic loading, including shape memory alloy (SMA)-built specimens. In the post-analysis phase, the T-stub thickness, the T-stub yield strength, the bolt preload and bolt number, and the stiffener type and stiffener material for the most significant parts of the DST connection were calculated. Simulation results showed that a lower ultimate moment yielded fewer needed stem bolts. The energy dissipation (ED) capacity increased as the horizontal distance between the stem bolts decreased. Additionally, increasing the strength of the bolt and T-stub by 15% resulted in a 3.86% increase in residual displacement (RD) for the bolt and a 1.73% decrease in residual displacement for the T-stub. T-stub stiffeners enhanced ED capacity by 31.7%. SMA materials were vulnerable to mode 1 failure when used in T-stubs, bolts, or stiffeners. However, the use of SMA increased the rate of energy dissipation. Adding stiffeners to the T-stubs altered the failure indexes and improved the pattern of failure modes. In addition, stiffeners decreased the rupture and pressure indexes. As a result, the failure index of a T-stub shifted from brittle failure to ductile failure.
... The configurations of the specimens involved cases where both T-stubs were identical, as well as cases where the connected T-stubs were different from each other. A comprehensive work has been carried out by Fernández-Ceniceros [35][36][37] to predict the complete forcedisplacement curve of bolted connections. FE modelling and softcomputing techniques were integrated into a hybrid method to yield an accurate estimation of connection behaviour. ...
An equivalent T-stub model is an essential tool for the prediction of the behaviour of steel bolted connections. It is usually employed to represent the tension-loaded components of bolted connections. Due to its importance, the T-stub model has been extensively investigated over the years, leading to design predictions for strength and stiffness. A common characteristic of the behaviour of the T-stub component is the prying effects which can develop due to the deformation of the flange of the T-stub. It can cause a substantial bolt force increase and bolt bending. The flexural engagement of bolts have been disregarded in most studies that investigated prying in bolted T-stubs. However, the combined action of tension and bending can be detrimental to the bolts. This paper provides a state-of-the-art review of the experimental, numerical, and analytical studies on the behaviour of bolted T-stubs in general, and on prying action in particular.
Tools and methods used by architects always had an impact on the way building were designed. With the change in design methods and new approaches towards creation process, they became more than ever before crucial elements of the creation process. The automation of architects work has started with computational functions that were introduced to traditional computer-aided design tools. Nowadays architects tend to use specified tools that suit their specific needs. In some cases, they use artificial intelligence. Despite many similarities, they have different advantages and disadvantages. Therefore the change in the design process is more visible and unseen before solution are brought in the discipline. The article presents methods of applying the selected artificial intelligence algorithms: swarm intelligence, neural networks and evolutionary algorithms in the architectural practice by authors. Additionally research shows the methods of analogue data input and output approaches, based on vision and robotics, which in future combined with intelligence based algorithms, might simplify architects everyday practice. Presented techniques allow new spatial solutions to emerge with relatively simple intelligent based algorithms, from which many could be only accomplished with dedicated software. Popularization of the following methods among architects, will result in more intuitive, general use design tools.
Two types of sampling plans are examined as alternatives to simple random sampling in Monte Carlo studies. These plans are shown to be improvements over simple random sampling with respect to variance for a class of estimators which includes the sample mean and the empirical distribution function.
In this paper, we describe an artificial neural networking (ANN) model developed to predict the moment-rotation response of semi-rigid beam-to-column joints at elevated temperature. Five types of beam-to-column joints, which represent typical joints used in construction, were modelled. Three flush end-plate bare-steel joints, one flexible end-plate bare-steel joint and two flexible end-plate composite joints were considered. The applied moment and joint's temperatures were used as input parameters to model the rotational capacity of the joint with increasing temperatures. Data from 20 experimental fire tests were used for training and testing and validating the neural network models. The model's predicted values were compared with actual test results. The results indicate that the models can predict the moment-rotation-temperature behaviour of semi-rigid beam-to-column joints with very high accuracy. The developed model can be modified easily to investigate other parameters that influence the performance of joints in fire.
This standard specifies a method for tension testing of metallic structural materials, for determining stress-strain relations up to the maximum load under monotonic and uniaxial tensile loading at ambient temperature. The stress-strain relations shall be expressed by some standardized mathematical equations, in which the material constants shall be evaluated in accordance with the appendices in this standard. The text presented is a draft which is published in order to be submitted to comments. The final text will be drawn from the draft with regard to the possible comments.
Despite the large database of test results on block shear in gusset plates, the exact progression of the failure mechanism is not clear. Although current design equations predict the block shear capacity of gusset plates fairly well, it is important for a design equation not only to predict the capacity reliably, but also to predict accurately the failure mode. Current research at the University of Alberta makes use of a non-linear finite element model to study the block shear behaviour in gusset plates. The model was designed to predict the sequence of events that leads to the tear-out of a block of material from a gusset plate in tension. The model is developed to provide a useful tool to study block shear failure not only in gusset plates, but also in other members such as coped beams. This thesis presents the development of the finite element procedure for prediction of block shear failure in gusset plates and presents an assessment of several design equations for block shear in gusset plates. A limit states design equation that predicts well the observed failure mode and provides an adequate level of safety is proposed.
Engineering Damage Mechanics is deliberately oriented toward applications of Continuum Damage Mechanics to failures of mechanical and civil engineering components in ductile, creep, fatigue and brittle conditions depending upon the thermomechanical loading and the materials: metals and alloys, polymers, elastomers, composites, concretes. Nevertheless, to help engineers, researchers, beginners or not, the first two chapters are devoted to the main concepts of damage mechanics and to the associated computational tools.