Analysis Of Structural Behavior Research Articles

Modeling the atomistic growth behavior of gold nanoparticles in solution.

The properties of gold nanoparticles strongly depend on their three-dimensional atomic structure, leading to an increased emphasis on controlling and predicting nanoparticle structural evolution during the synthesis process. In order to provide this atomistic-level insight and establish a link to the experimentally-observed growth behavior, a kinetic Monte Carlo simulation (KMC) approach is developed for capturing Au nanoparticle growth characteristics. The advantage of this approach is that, compared to traditional molecular dynamics simulations, the atomistic nanoparticle structural evolution can be tracked on time scales that approach the actual experiments. This has enabled several different comparisons against experimental benchmarks, and it has helped transition the KMC simulations from a hypothetical toy model into a more experimentally-relevant test-bed. The model is initially parameterized by performing a series of automated comparisons of Au nanoparticle growth curves versus the experimental observations, and then the refined model allows for detailed structural analysis of the nanoparticle growth behavior. Although the Au nanoparticles are roughly spherical, the maximum/minimum dimensions deviate from the average by approximately 12.5%, which is consistent with the corresponding experiments. Also, a surface texture analysis highlights the changes in the surface structure as a function of time. While the nanoparticles show similar surface structures throughout the growth process, there can be some significant differences during the initial growth at different synthesis conditions.

Self-Relatedness and Interpersonal Problems in a Large Psychiatric Outpatient Sample

Interpersonal- and self-relatedness problems are strongly correlated on a global level. However, few studies have examined associations between distinct forms of interpersonal problems and specific types of problems in self-relatedness. We hypothesized that patients with domineering interpersonal problems would exhibit a more positive self-image than patients with submissive interpersonal features. We also wanted to examine if the self-hostile and self-accepting aspects of patients’ self-relatedness were differentially associated with their interpersonal problems. A large clinical outpatient sample (N = 958) was divided into eight subgroups (Octant Groups) of patients with different predominant interpersonal problems, as measured with the 64 item version of the Inventory of Interpersonal Problems—IIP-64. Self-relatedness was measured with the Introject surface of the Structural Analysis of Social Behavior—SASB Introject. ANCOVA analyses showed that patients with more positive and self-accepting self-images displayed domineering, but also warmer forms of interpersonal problems than peers with more negative self-images. Dividing the self-relatedness variable into Self-Hostile and Self-Accepting components yielded a new finding: patients within different interpersonal Octant Groups differed significantly with regard to Self- Acceptance, but not with respect to Self-Hostility. The former component may be reflective of a more stable personality feature than Self-Hostility, thereby rendering it less susceptible to change.

Prediction of stress–strain behavior of spirally confined concrete considering lateral expansion

This paper proposes a new analytical model for the relationship between the axial and transverse strains of confined concrete in uniaxial compression. The proposed model was developed based on empirical data for a circular section confined by spirals. A column with a circular section and subjected to uniaxial compression was considered. The proposed model predicts the stress in the transverse confinement reinforcement to estimate the relationship between the axial strain of the column and tensile strain of the transverse confinement reinforcement. The model can also produce the axial stress–strain relationship of the confined concrete of the column. The predicted axial and transverse strains of the confined concrete section corresponded to the observed axial peak stress of a column evaluated in previous research with good accuracy. This model will be an effective tool for investigating the effect of circular spirals on the structural behavior of confined concrete and enhancing the accuracy of structural behavior analysis for a column under uniaxial compression.

Analysis of band structure, transmission properties, and dispersion behavior of THz wave in one-dimensional parabolic plasma photonic crystal

The photonic band gap of obliquely incident terahertz electromagnetic waves in a one-dimensional plasma photonic crystal is studied. The periodic structure consists of lossless dielectric and inhomogeneous plasma with a parabolic density profile. The dispersion relation and the THz wave transmittance are analyzed based on the electromagnetic equations and transfer matrix method. The dependence of effective plasma frequency and photonic band gap characteristics on dielectric and plasma thickness, plasma density, and incident angle are discussed in detail. A theoretical calculation for effective plasma frequency is presented and compared with numerical results. Results of these two methods are in good agreement.

Use of Tire Rubber Residue in Reinforced Concrete Pipes

The concrete material has many advantages as high durability, low permeability, weather resistance and high compressive strength. These qualities have led its application to the rainwater collection since the pipes are usually buried, subject to compressive forces and exposed to the action of water. However, the concrete has some limitations, as, for example, low resistance to tensile stress, high self-weight, ease of cracking and brittle behavior in rupture. Thus, many materials are being studied in order to be used as a new concrete component seeking to minimize its disadvantages. One of them is the tire rubber residue. This residue is a fibrous material that takes a long time to decompose and increases the amount of trash in landfills; but, it may give a greater deformation capacity and also a more effective distribution of stresses to the concrete. Furthermore, the tire rubber residue can provide an increase in energy absorption and a decrease in the propagation of cracks in the hardened state. However several studies mention that the inclusion of the waste rubber into the concrete causes a decrease in mechanical strength to compression, a decrease in the workability of the mixtures and an increased content of entrained air. Therefore, an analysis of the structural behavior of four (4) reinforced concrete pipes was made: two (2) of them was molded without tire rubber residue and the other two (2), with a quantity of residue equal to 20 kg per cubic meter of concrete. All the pipes had a nominal diameter of 600 mm and an effective length of 1500 mm; they were subject to the crushing test standardized by the Brazilian Association of Technical Standards - NBR 8890 (ABNT, 2007) which is similar to the European standard NBN-EM 1616. The diametric displacements at the hub and at the spigot were monitored by the use of two dial gauge indicators. The applied force by a hydraulic jack was measured using a cell load. Finally, tests of water absorption using pieces of the tested pipes were performed, based on the recommendations of the NBR 8890 (ABNT, 2007).

Analysis of structure and deformation behavior of AISI 316L tensile specimens from the second operational target module at the Spallation Neutron Source

In an earlier publication, tensile testing was performed on specimens removed from the first two operational targets of the Spallation Neutron Source (SNS). There were several anomalous features in the results. First, some specimens had very large elongations (up to 57%) while others had significantly smaller values (10–30%). Second, there was a larger than the usual amount of data scatter in the elongation results. Third, the stress–strain diagrams of nominally similar specimens spanned a wide range of behavior ranging from expected irradiation-induced hardening to varying levels of force drop after yield point and indirect signs of “traveling deformation wave” behavior associated with strain-induced martensite formation. To investigate the cause(s) of such variable tensile behavior, several specimens from Target 2, spanning the range of observed tensile behavior, were chosen for detailed microstructural examination using electron backscatter diffraction (EBSD) analysis. It was shown that the steel employed in the construction of the target contained an unexpected bimodal grain size distribution, containing very large out-of-specification grains surrounded by “necklaces” of grains of within-specification sizes. The large grains were frequently comparable to the width of the gauge section of the tensile specimen. The propensity to form martensite during deformation was shown to be accelerated by radiation but also to be very sensitive to the relative orientation of the grains with respect to the tensile axis. Specimens having large grains in the gauge that were most favorably oriented for production of martensite strongly exhibited the traveling deformation wave phenomenon, while those specimens with less favorably oriented grains had lesser or no degree of the wave effect, thereby accounting for the observed data scatter.

Evolution of the amorphous structure in melt-spun Ti50Ni25Cu25 alloy subjected to high pressure torsion deformation

Peculiarities of structure and mechanical behaviour of amorphous Ti50Ni25Cu25 alloy were the focus of this research. The melt-spun ribbons of amorphous Ti50Ni25Cu25 were subjected to high pressure torsion (HPT) at temperatures of 20–150 °C in order to modify their structure and mechanical behaviour. Some features of obtained HPT-processed samples were compared with initial state with the help of x-ray diffraction (XRD), transmission electron microscopy (TEM) and nanohardness testing. Analysis of structural data and mechanical behaviour allowed us to assume that severe plastic deformation (SPD) processing of melt-spun Ti50Ni25Cu25 alloy might lead to the formation of the structure similar to the new kind of noncrystalline state – “nanoglass” state.

Dynamic Nonlinear Analysis of Semi-Rigid Steel Frames Based on the Finite Particle Method

The Finite Particle Method (FPM), based on the Vector Mechanics, is a new structural analysis method. This paper explores the possibility of the proposed method being applied in the dynamic nonlinear analysis of semi-rigid steel frames. Taking the two dimensional beam element as an example, the formulations of the FPM to calculate the dynamic and geometric nonlinear problems are derived. Spring model with zero-length is adopted to simulate the relationship between internal forces and deformations of the semi-rigid steel connections. The nonlinear strengthen spring model is used to analyze the nonlinear behavior of the semi-rigid connection. Explicit time integrations are used to solve equilibrium equations. Comparing to traditional Finite Element Method, iterations and special modifications are not needed during the dynamic nonlinear analysis, which is more advantageous in structural complex behavior analysis. Two numerical examples are presented to analyze the behaviors of rigid and semi-rigid steel frames, and behaviors of linear and nonlinear semi-rigid connections, which demonstrate the accuracy and applicability of this method in dynamic nonlinear analysis.

An improved peridynamic approach for quasi-static elastic deformation and brittle fracture analysis

An extended bond-based peridynamic (PD) approach is presented for quasi-static mechanical behavior and brittle failure analysis of materials and structures. A local artificial damping is introduced into the peridynamic equations of motion, and a step-by-step loading method and a non-equilibrium criterion are employed to calculate the elastic response quantitatively, simulate the crack initiation and propagation and predict the extreme failure load of structures. The effect of the magnitude of the local damping on the accuracy and efficiency of elastic calculation is investigated. In the proposed model, another important feature lies in the micromodulus of the pair-wise bond, which is described as a continuous function of the distance between two particles within the material horizon and is demonstrated to be more accurate when compared to the earlier PD models using a fixed stiffness constant to describe the interaction of particles. The qualitative and quantitative validity of the approach is established through simulating the mechanical response and fracture of a cantilever concrete beam, including the whole process from the earlier elastic deformation stage to crack initiation and propagation, and making comparisons to the analytical and other numerical data. To further demonstrate the capabilities of the proposed model, the crack propagation and fracture mechanism of a cantilever concrete beam with pre-existing notch is studied, and the effect of the notch location on the extreme failure load and fracture mode of the structure is examined.

Influence of Time Evolution in the Modulus of Elasticity of Concrete Reinforced by Carbon Fibers

The modulus of elasticity is an important property for the behavior analysis of concrete structures. This research evaluated the strain difference between concrete specimens with and without the application of laminate carbon fiber composites as well as the variation time, in months, of the axial strength compression and modulus of elasticity. Through the experimental results, it is concluded that increases in compressive strength and modulus of elasticity are more significant in the specimens without reinforcement.

Structural Analysis of Low Level Gambling Behavior in College Students

Structural Analysis of Low Level Gambling Behavior in College Students

Structural Behavior Analysis of Concrete Encased and Filled tube Square Column with Construction Sequence

구조물의 기둥은 층에 따라 받는 내력이 상이함에도 시공의 오차를 줄이고 구조설계의 편의를 위해 상부층부터 하부층의 기둥단면은 동일하게 설계되고 있다. 그럼에도 불가피하게 상하부의 기둥의 단면이 상이하는 경우가 발생된다. 예를들어 초고층 구조물 또는 증축 및 보수에 의해 기둥을 보강할 경우이다. 이렇듯. 선 기둥과 후 피복이 되는 기둥을 피복충전형 콘크리트 충전기둥이라 할 때, 가력조건이 다르므로 재하상태를 나뉘어 구조적 안정성을 확인할 필요가 있다. 그럼에도 국내외적으로 가력조건에 따른 합성기둥에 대한 내력과 변형연구는 전무한 상태에 있다. 따라서 본 연구에서는 구조실험을 통해 가력조건 및 콘크리트 강도, 피복두께 변화에 의한 피복충전형 콘크리트 각형 기둥의 내력과 거동을 분석하였다. Constructions of buildings downtown are increasing as much as ever with a strong demand. Top-Down Method is suitable for its advantage in minimizing its disturbance to the neighborhood. Pre-founded when applied to CFT Column on-site welded is required for splicing. To complement the welded built-up square composite Column was developed. Top-down process will be pouring concrete in accordance with a step-by-step process. Thus, Pre-founded Column and cover concrete to determine the stress condition. Therefore, Concrete filled steel square tubular columns encased with precast concrete were studied. Five Centrally loaded Columns were tested to investigate the axial load carrying capacity. we analyzed the strength and behavior of CET Column by Loading conditions and concrete strength, thickness of cover concrete through structure experiments.

Non-linear incidental dynamics of frame structures

A simulation of failures on responsible elements is only one form of the extreme structural behavior analysis. By understanding the dynamic behavior in incidental situations, it is possible to make a special structural design from the point of the largest axial force, stress and redundancy. The numerical realization of one such simulation analysis was performed using FEM in this paper. The boundary parameters of transient analysis, such as overall structural damping coefficient, load accelerations, time of load fall and internal forces in the responsible structural elements, were determined on the basis of the dynamic experimental parameters. The structure eigenfrequencies were determined in modal analysis. In the study, the basic incidental models were set. The models were identified by many years of monitoring incidental situations and the most frequent human errors in work with heavy structures. The combined load models of structure are defined in the paper since the incidents simply arise as consequences of cumulative errors and failures. A feature of a combined model is that the single incident causes the next incident (consecutive timing) as well as that other simple dynamic actions are simultaneous. The structure was observed in three typical load positions taken from the crane passport (range-load). The obtained dynamic responses indicate the degree of structural sensitivity depending on the character of incident. The dynamic coefficient KD was adopted as a parameter for the evaluation of structural sensitivity.

Investigation into long-term behaviour and stability of concrete-filled steel tubular arches

This paper presents the long-term structural behaviour analysis and stability assessment carried out on concrete-filled steel tubular (CFST) circular arches. Linear and non-linear analyses are herein conducted for pin-ended and fixed arches subjected to a central concentrated load. Accounting for the significant effects from creep and shrinkage in concrete core, in-plane deformations, internal forces and in-plane buckling loads are evaluated analytically and the adequacy is validated against the finite element results. The comparison of the results obtained by linear and non-linear analyses exhibits significantly different change scopes in deformation and loading capacity. For the sake of structural safety, non-linear analysis is found to be more reliable in long-term behaviour analysis and stability assessment for CFST arches. Hence, non-linear buckling analysis should be employed in assessing the long-term serviceability limit state of pin-ended and fixed CFST shallow arches in design practice, although linear buckling analysis is capable of predicting the in-plane buckling loads for pin-ended CFST deep arches.

Nonlinear Finite Element Analyses of FRP-Strengthened Concrete Slabs under Fixed-Point Cyclic Loading

AbstractA finite element model denoted as FEM-C is developed in this paper for prediction of structural responses of fiber-reinforced polymer (FRP)–strengthened concrete slabs under fixed-point cyclic load. First, a finite element model named as FEM-S, which is of the same geometry as the FEM-C model, is developed and validated for analyses of structural behavior of FRP-strengthened concrete slabs under static load. Then, the finite element model is extended for analyses of structural behavior of FRP-strengthened reinforced concrete (RC) slabs under fixed-point cyclic loading in the FEM-C model, with degradations of material properties of concrete, steel reinforcement, and FRP due to cyclic loading taken into account. Geometric and material nonlinearity and bond-slip effects between FRP and concrete are included in these models. The finite element (FE) models are validated through numerical examples and demonstrated to be effective and accurate for modeling the structural behavior of FRP-strengthened RC s...

Formation of amorphous states in Ti50Ni25Cu25 alloy subjected to severe plastic deformation: Nanoglass issue

Peculiarities of structure and mechanical behaviour of amorphous Ti50Ni25Cu25 alloy were the focus of this research. Amorphous melt-spun ribbons and bulk crystalline samples were subjected to high pressure torsion (HPT) in order to modify their structure and mechanical behaviour. Some properties of obtained SPD-processed samples were compared with initial state with the help of x-ray diffraction (XRD), differential scanning calorimetry (DSC) and nanohardness tests. It was shown that according to XRD no nanocrystallization occurs during HPT of melt-spun ribbons yet at the same time high density of shear bands might be formed in the alloy. Due to the formation of shear bands with the excess free volume the decrease of hardness and crystallization temperature were observed in the alloy. Analysis of structural data and mechanical behaviour allowed us to assume, that SPD processing of melt- spun Ti50Ni25Cu25 alloy might lead to the formation of structural state similar to the new kind of noncrystalline state – "nanoglass" state.

Allowing for changes in the calculated scheme during the analysis of structural behaviour

Allowing for changes in the calculated scheme during the analysis of structural behaviour

Analysis of structural phase transition behavior of Ln2NiO4 + δ (Ln: Nd, Pr) with variation of oxygen content

The orthorhombic-tetragonal structural phase transition behaviors of Pr2NiO4+δ and Nd2NiO4+δ were investigated by DSC and TG–DTA under controlled oxygen partial pressure, P(O2), and their difference was discussed. A discrete weight variation originating from the variation of oxide ion content, Δδ, was observed during the phase transition in both Pr2NiO4+δ and Nd2NiO4+δ. The Δδ of Pr2NiO4+δ was larger than that of Nd2NiO4+δ, and the Δδ of Pr2NiO4+δ increased with decreasing P(O2), while that of Nd2NiO4+δ was independent on P(O2), suggesting that not only the valence of Ni but also that of Pr changed during the phase transition in Pr2NiO4+δ.

Soil-structure interaction effects on RC structures within a performance-based earthquake engineering framework

Performance-based earthquake engineering (PBEE) has emerged as a powerful method of analysis and design philosophy in earthquake engineering. Structures are generally assumed to be fixed at their bases in the process of analysis and design under dynamic loading. Response of structures under earthquakes is strongly influenced by the soil-structure system. In soil-structure interaction (SSI) problems, the ability to predict the coupled behaviour of the soil and the structure is essential and requires combined soil and structure models. In the context of PBEE, this paper combines structural behaviour and seismic response analysis of SSI systems. Related to SSI analysis, several issues are studied, such as relative importance of soil parameters, and relative foundation/soil stiffness ratio, in regards to a specified aspect of the system response (e.g. response parameters). A simplified approach is proposed to consider SSI effects on the nonlinear seismic response of a reinforced concrete structure using the nonlinear replacement oscillator method. This oscillator is characterised by an effective ductility along with the known effective period and damping of the system for the elastic condition. The N2 method is used to determine the nonlinear response and extended to include SSI in the design. It is confirmed that the response of the structure depends not only on its dynamic characteristics and on the seismic excitation characteristics but also on the external environment surrounding the base of the structure, i.e. the interaction between the structure, the foundation and the soil. The proposed approach is validated and compared with time history analysis and two other recognised methods.

Depression, relationship quality, and couples' demand/withdraw and demand/submit sequential interactions.

This study investigated the associations among depression, relationship quality, and demand/withdraw and demand/submit behavior in couples' conflict interactions. Two 10-min conflict interactions were coded for each couple (N = 97) using Structural Analysis of Social Behavior (SASB; Benjamin, 1979a, 1987, 2000a). Depression was assessed categorically (via the presence of depressive disorders) and dimensionally (via symptom reports). Results revealed that relationship quality was negatively associated with demanding behavior, as well as receiving submissive or withdrawing behavior from one's partner. Relationship quality was positively associated with withdrawal. Demanding behavior was positively associated with women's depression symptoms but negatively associated with men's depression symptoms. Sequential analysis revealed couples' behavior was highly stable across time. Initiation of demand/withdraw and demand/submit sequences were negatively associated with partners' relationship adjustment. Female demand/male withdraw was positively associated with men's depression diagnosis. Results underscore the importance of sequential analysis when investigating associations among depression, relationship quality, and couples' interpersonal behavior.