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This paper aims to thoroughly investigate the free vibration characteristics of rectangular plates resting on symmetrically distributed four rigid supports by using a finite element (FE) method.

ANSYS parametric design language was used to generate the FE models and to run the analysis. The FE models were initially validated and were then used to solve for the plate first natural frequency and mode shape. The effect of the plate aspect ratio and support location on the free vibration properties of the plate was thoroughly studied by conducting several FE runs. Finally, simple empirical formulas were developed to conveniently calculate the plate first natural frequency based on the geometric parameters and support type, as well as support locations. Those well-formulated equations were in a great match with the FE data.

The results showed that the plate first natural frequency and mode shape are highly affected by the plate size and support locations. Specifically, the natural frequency deceases as the plates becomes larger. Also, the bending behavior of the first mode is highly affected by the support location, which results in a significant change in the natural frequency of the plate structure. In addition, the presently formulated empirical formulas are faithfully able to predict the natural frequency of the plate based on the geometric parameters and support location.

This paper provides numerous new data on the vibration properties of the rectangular plate resting on rigid supports. Also, it provides a simple way to easily calculate the natural frequency of this plate problem, unlike the very limited and complicated analytical solutions available in literature.

The purpose of this paper is to present a ribbons production route of composition Fe₇₈Si₉B₁₃ (%at.) using low cost noncommercial scrap materials to obtain usable magnetic cores by melt spinning technique and their characterization. This way, these may compete with the materials produced by conventional casting processes.

The methodology is to design a master alloy with scrap different starting compositions, to which Fe is added to get the desired atomic ratio of components. With this starting alloy, using the method of melt spinning, in its variant of chill block melt spinning, are achieved amorphous ribbons with desired soft magnetic behavior. Then these ribbons are thermally treated for achieve nanocrystalline structures to improve the performance in the magnetic cores.

The result of this paper shows that it is possible to recycle scrap materials, and re-used efficiently as components essential in part of electrical components. This way, these may compete with the materials produced by conventional casting processes.

The limitation of this work to ensure that the scrap materials used is reasonably adequate to accomplish obtaining the master alloy, i.e. having reduced impurities.

The implications are important, because it assures that the components are recyclable and also high-tech in reference to energy saving that involves the production of amorphous and nanocrystalline materials in the electric industry. These products may compete with those produced by conventional casting processes.

The social implications lead to awareness in recycling and energy saving as an option for social progress in technology.

The originality of the study is that it takes as a starting point for the final product (ribbon) noncommercial scrap materials of known composition and the obtained results are comparable to those that also are manufactured from the pure elements. The control of impurities is necessary in the production route. This way, these may compete with the materials produced by conventional casting processes. This process achieved a production with lower cost, high efficient energy products and high added value.

This paper aims to fast predict vibration responses of specific locations in the satellite subject to acoustic environment. It proposes a set of vibro-acoustic simulation methods of satellite components to represent their conditions in the whole satellite during the ground tests or launching. This study aims to use vibro-acoustic models of satellite components to replace that of hard modeling and time-consuming whole satellite when only local responses are concerned.

This paper adopted experimental and numerical studies, with the latter based on the finite element (FE), statistical energy analysis (SEA) and FE-SEA hybrid theories. The vibro-acoustic model of the whole satellite was built and verified by experimental data. Based on the whole satellite model and experimental results, the fast vibro-acoustic simulation methods of all kinds of typical satellite components were discussed.

This paper shows that the models about satellite components not only show high consistency but also reduce 61.6% to 99.8% times compared with the whole satellite model. The recommended fast simulation methods for all kinds of typical satellite components were given in comprehensive consideration of the model accuracy, time required and response accessibility.

This paper fulfils an identified need to perform fast vibro-acoustic prediction of the local positions in satellites.

This paper aims to present the findings of a numerical investigation into the performance of the steel-concrete composite floor involved in Broadgate Phase 8 fire.

The investigation is conducted by carrying out a 3-D thermomechanical analysis of a composite floor similar to the one involved in the fire using ANSYS. Four fire scenarios are investigated, with each producing a unique stress – strain pattern. The results obtained are compared with the observations made after the fire and inferences drawn.

The results obtained are found to be correlated with the observations made after the fire. The performance of the composite floor is found to be dominated by development of large strains, leading to large deflections. Furthermore, colder parts of the structure, through redistribution of forces, are found to have a profound impact on the ability of a composite floor to resist heating effects. From the findings, it is concluded that connections’ design, occurrence of membrane action and thermal restraints were the key reasons the floor did not fail.

The study takes a more forensic approach. This is a departure from majority of published literature, where comparison is usually between experimental and numerical results. By comparing the findings from a real fire with those of a numerical investigation, the study provides an insight into the accuracy of applying numerical models for the prediction of effects of fire on structural behaviour.

The paper's aim is to devise a fast method for microwave waveguide filter permittivity tolerance analysis.

A 2D finite elements (FEs) formulation is combined via a Schur complement‐based domain decomposition (DD) technique to reduce the tolerance affected part of the analysis to a smaller domain.

The paper shows how to combine FEs and DD in an efficient way for material parameters tolerance analyses in microwave waveguide filters, showing speedup results.

The formulation here presented is 2D but can be easily extended to 3D.

The application of DD to solve numerically large problem is well‐known, the idea and organization of the algorithm to allow iteration on parameter values on a single sub‐domain is here proposed.

Top-seat angle connection is known as one of the usual uncomplicated beam-to-column joints used in steel structures. This article investigates the fire performance of welded top-seat angle connections.

A finite element (FE) model, including nonlinear contact interactions, high-temperature properties of steel, and material and geometric nonlinearities was created for accomplishing the fire performance analysis. The FE model was verified by comparing its simulation results with test data. Using the verified model, 24 steel-framed top-seat angle connection assemblies are modeled. Parametric studies were performed employing the verified FE model to study the influence of critical factors on the performance of steel beams and their welded angle joints.

The results obtained from the parametric studies illustrate that decreasing the gap size and the top angle size and increasing the top angles thickness affect fire behavior of top-seat angle joints and decrease the beam deflection by about 16% at temperatures beyond 570 °C. Also, the fire-resistance rating of the beam with seat angle stiffener increases about 15%, compared to those with and without the web stiffener. The failure of the beam happens when the deflections become more than span/30 at temperatures beyond 576 °C. Results also show that load type, load ratio and axial stiffness levels significantly control the fire performance of the beam with top-seat angle connections in semi-rigid steel frames.

Development of design methodologies for these joints and connected beam in fire conditions is delayed by current building codes due to the lack of adequate understanding of fire behavior of steel beams with welded top-seat angle connections.

Concrete arch structures are commonly constructed for various civil engineering applications. Despite their frequent use, there is a lack of research on the response and performance of concrete arches when subjected to fire loading. Hence, this paper aims to investigate the response and in-plane failure modes of shallow circular concrete arches subjected to mechanical and fire loading.

This study is conducted through the development of a three-dimensional finite element (FE) model in ANSYS. The FE model is verified by comparison to a non-discretisation numerical model derived herein and the reduced modulus buckling theory, both used for the non-linear inelastic analysis of shallow concrete arches subjected to uniformly distributed radial loading and uniform temperature field. Both anti-symmetric and symmetric buckling modes are examined, with analysis of the former requiring geometric imperfection obtained by an eigenvalue buckling analysis.

The FE results show that anti-symmetric bifurcation buckling is the dominant failure mode in shallow concrete arches under mechanical and fire loading. Additionally, parametric studies are presented which illustrate the influence of various parameters on fire resistance time.

Fire response of concrete arches has not been reported in the open literature. The authors have previously investigated the stability of shallow concrete arches subjected to mechanical and uniform thermal loading. It was found that temperature greatly reduced the buckling loads of concrete arches. However, this study was limited to the simplifying assumptions made which include elastic material behaviour and uniform temperature loading. The present study provides a realistic insight into the fire response and stability of shallow concrete arches. The findings herein may be adopted in the fire design of shallow concrete arches.

This paper aims to present the assumptions, analysis and sample results of numerical modeling and analysis of dynamic events encountered in emergency cases during deployment of parachute rescue system (PRS) and hard landing of a small gyrocopter. The optimal design requires knowledge of structural loads and structural response – the information obtained often from experiment. Numerical simulation is presented as an alternative tool for estimating these data.

Structural analyses were performed using MSC.Nastran. Multibody simulations were done using MADYMO system.

Initial design parameters were evaluated and verified in numerical simulations. Some of the resulting conclusions were proven during the test flights.

Some chosen results of simulation of dynamic problems are presented. They can be useful as reference values for similar cases for light aircraft analysis.

The paper presents an alternative way of assessing structural response parameters in the case of emergency dynamic events of usage of PRS. The results can be used in other projects.

Concrete-filled double-skin tubular (CFDST) columns have been gaining significant attention since these columns proved to be more efficient compared to concrete-filled steel-tubular (CFST) columns. This paper presents a tool to design slender CFDST columns with/without inclination.

First, 3D nonlinear finite element (FE) models of twenty-two straight CFDST columns are calibrated and it is found that FE results are in good agreement with the experimental outcomes. This is validated based on available experimental data. Subsequently, a parametric study is conducted by adjusting each calibrated FE model to account for three different angles of inclination. These models are used to quantify the effective length factor of these inclined columns.

It is found that FE results are in good agreement with the experimental outcomes. An equation is developed in this paper to calculate the characteristic concrete compressive strength for the design of straight CFDST columns. In addition, an equation is presented for engineering practice to calculate the effective length factor at different inclination angles and slenderness ratios to design CFDST columns. The predicted load capacity compares well with the experimental results of straight columns and FE results of inclined columns.

Advancement in the structural design procedure is required as a response to the continuous innovations in architectural design. Designers might introduce an inclination in columns in buildings or bridges, and there are no available guidelines to design them.

The breasts are mainly fatty and connective tissues with no muscles that directly support them, so wearing sports bras is one of the most effective means of alleviating the discomfort of breast movement and potential injury during vigorous physical exercise. However, the design and development processes of traditional sports bras are time-consuming and costly. Hence, a novel method of simulating the static contact pressure between a sports bra and women’s body based on the finite element (FE) and artificial neural network (ANN) models is developed in this study to contribute to the design considerations of sports bras.

Three-dimensional FE models of a female subject and sports bras with different fabric properties are developed to determine the amount of contact pressure exerted onto the body. The FE results are then verified by measuring the amount of pressure exerted by the sports bra on the skin with pressure sensors. The Taguchi technique is used to effectively reduce the number of trials from 625 to only 25 cases. These 25 results obtained through FE modelling are then used to provide the training set for the ANNs. Finally, a comparison between the FE and ANN results is carried out.

A novel model of the static contact pressure between a sports bra and human subject based on the FE and ANN methods is presented in this paper. The root mean square error values show that there is only a small difference between the FE and ANN results.

The ANN function established in this study can be used to predict the mechanical behaviours of breasts and has a fundamental impact on the computer-aided design of functional garments in general.