Stress-deformed state of a three-layer structure taking into account the hypothesis of cubic displacement pattern over the thickness of a filler

Objective. In most cases, when determining the stress-deformed state of three-layer structures, it is assumed that bearing layers obey the Kirchhoff-Love hypothesis, while a filler obey the Neit (vanderNeit), or “broken line”, hypothesis. But in many cases, the results of our research show that this is not always accurate. Methods. It is proposed to solve the three-dimensional problem of determining the stress-deformed state of a three-layer structure using cubic functions of the law of aggregate deformation distribution along the normal line, obtained on the basis of the law of deformation compatibility at “filler – bearing layer” boundaries and the construction of boundary conditions in joint zones. Results. Equilibrium equations of a three-layer beam obtained on the basis of this hypothesis are shown in Table 1. The given partial differential equations are of the 12th order and we transformed them into homogeneous equations of the 1st order to simplify the solution. This solution is implemented using the mathematical modelling software package Mаple 5.4. Conclusion. The work of the filler in the direction of OX axis has a certain value, which affects the overall stress state of the three-layer structure (in existing hypotheses, it is zero).

Discovering Intra-Urban Population Movement Pattern Using Taxis’ Origin and Destination Data and Modeling the Parameters Affecting Population Distribution

GPS-equipped vehicles are an effective approach for acquiring urban population movement patterns. Attempts have been made in the present study in order to identify the population displacement pattern of the study region using taxis’ origin and destination data, and then model the parameters affecting the population displacement pattern and provide an ultimate model in order to predict pick-up and drop-off locations. In this way, the passenger pick-up and drop-off locations have been identified in order to obtain the population movement pattern. In this study, Moran’s I index was used to measure the spatial autocorrelation, and hot spot analysis was used to analyze spatial patterns of pick-up and drop-off locations. Effective parameters modeling was performed using the Poisson regression. The results of the spatiotemporal distribution map for pick-up and drop-off locations indicated a similarity in patterns and equal results for some locations. Results also indicated different features of spatial distribution during different hours of the day. Spatial autocorrelation analysis results indicated a low probability of randomness in the general spatial distribution of the locations. The result of modeling the parameters shows the positive effect of the parameters on the pattern of population movement, and according to the p-value of 0.000, Poisson regression is significant for the pick-up and drop-off locations. The modeling results also highlighted the importance of movement patterns in recognizing urban hot spots, which is valuable for policymakers and urban planners.

Locomotion and righting behavior of sea stars: a study case on the bat star Asterina stellifera (Asterinidae)

Introduction: The locomotion behavior of an organism involves the integration of aspects like body symmetry, sensory and locomotor systems. Furthermore, various ecological factors seem to be related to locomotion characteristics, such as foraging strategy, migration trends, response to predators and competitors, and environmental stress. Objective: To analyze locomotion and the influence of body symmetry in the crawling and righting movements of the sea star Asterina stellifera. Methods: We carried out laboratory experiments in aquariums in the presence/absence of water current and on a horizontal and vertical surface. Results: The speed is similar to speed in other species of similar size. Both the speed and linearity of displacement were independent of individual body size. A water current leads to faster crawling and straight paths, but there is no rheotaxis: streams do not affect locomotion. Speed and linearity of displacement were independent of individual body size. The displacement pattern described here may be an adaptation of organisms that present dense populations in communities with high prey abundance, as is the case of A. stellifera. Conclusions: Like other asteroids, this species did not show an Anterior/Posterior plane of symmetry during locomotion, or righting movement: it does not tend to bilaterality.

A New Approach to the Modeling of Magnetorheological Dampers and Application to Resonance Control

A predetermined flow pattern in a magnetorheological damper providing continuously variable resistance to flow is required for efficient damping of a given load. The required predetermined flow pattern rests on the a priori determination of the constitutive properties of the magnetorheological (MR) fluid determined to generate variable resistance to flow. The inverse problem of constructing the predetermined response of the damper with a specific displacement pattern of the piston in the damper for efficient damping of a given load is solved. The magnetorheological (MR) fluid in the damper is modeled as a Bingham phase change material with time dependent yield stress offering continuously variable resistance to the flow in the piston to achieve the required specific displacement pattern. The governing equations are solved for any time history of the dimensionless yield stress of the fluid which in turn is determined from the imposed response of the damper. Analytical tools developed can be used in optimizing damper performance. The application of the method to resonance mitigation is illustrated.

Stability Numbers for Unsupported Conical Excavations in Multi-Layered Cohesive Soils

This paper presents the results of a numerical analysis into undrained stability of conical excavation in multi-layered clays. Stability predictions for a wide range of geometric and material combinations are calculated by finite element analyses. The results from the present analysis are expressed in the familiar form of stability numbers reflecting the effect of (1) angle of inclination, (2) depth ratio, which is relative top layer thickness to excavation depth, (3) strength difference between two layers on the rigid base, (4) width ratio, which is excavation height to radius at the bottom of excavation, and (5) thickness ratio, which is the ratio of the excavation height to thickness of soil 1 layers. The obtained stability numbers are compared with existing solutions published in the literature. The failure mechanism in multi-layered clays are also discussed in terms of the displacement pattern.

INVESTIGATION OF THE GROUND MOTION NEAR THE LEANING TOWER OF BAD FRANKENHAUSEN USING SENTINEL-1 PERSISTENT SCATTERER INTERFEROMETRY

Persistent Scatterer Interferometry (PSI) is a well-established technique for monitoring millimetre deformation of the Earth’s surface. The availability of free and open SAR data with a repeat cycle of 6–12 days from the Copernicus mission Sentinel-1, allows PSI to be used complementary to traditional surveying techniques. Whilst the data resolution may not allow a precise determination of the geolocation of the occurring deformation, observed deformation patterns can be analysed with auxiliary data and often show correlation with the location of geophysical processes or human activities. In this paper, we investigate the particular case of the church tower of Bad-Frankenhausen in the north of the Free State Thuringia, Germany, with PSI processing of Sentinel-1 data. Both pass directions (descending and ascending) are considered, and different motion models are tested in order to retrieve the most accurate displacement pattern around the church location. Deformation up to −6 mm/yr are observed near the church location for the period 2016–2019 in ascending direction.