Kinematic Interaction Research Articles

Seismic response of pile group embedded in unsaturated soil considering the coupling of kinematic and inertia pile-pile interactions

Both inertia and kinematic pile-soil-pile interaction should be considered during the seismic response analysis of a pile group. This study established a novel mathematical framework which is capable of considering the coupling of inertia and kinematic interactions, the complex constitutive of unsaturated soil, and the secondary wave effect within a pile group. By comparisons with existing analytical and numerical answers, the validity and advancement of the proposed model is exhibited. The main findings can be summarized as: (1) Simplified soil constitutive models, such as the BDWF model and the saturated soil model, would fail to reveal the authentic response of pile group. The saturation and porosity would significantly influence the kinematic pile-pile response factor, while the inertia pile-pile response factor is less influenced; (2) increases of pile numbers within a pile group would impose severe fluctuations on the kinematic response of the pile group, whereas the increase of pile spacing would significantly diminish this effect; (3) secondary wave effect should never be overlooked in seismic analysis but can be neglected in inertia analysis.

Kinematic Interactions Between Bones, Patellar Tendon, And Cartilage Surfaces During Cycling By Three-dimensional Fluoroscopic Imaging

Kinematic Interactions Between Bones, Patellar Tendon, And Cartilage Surfaces During Cycling By Three-dimensional Fluoroscopic Imaging

Performance of an advanced sand constitutive model in modelling soil and soil-structure interaction under seismic excitation

There is a growing number of available advanced soil constitutive models aimed at capturing soil cyclic behaviour and their subsequent use in seismic applications. Nevertheless, detailed validation studies of these soil constitutive models on benchmark experimental works including seismic soil-structure interaction are still rare. This work presents a short validation study of the seismic performance of an advanced elastoplastic sand constitutive model on a boundary value problem including kinematic and inertial soil-structure interaction. The results of the finite element numerical model for the free field and structural responses are compared with the experimental work on a group of piles analysed in a flexible soil container filled with dry sand and subjected to simplified seismic loading. In general, the comparisons show a satisfactory match between the results of the simulations and the experiments, with the exception of the numerical predictions of settlements. The computed results are discussed based on: i) the dominant stress-paths in soil; ii) parametric studies on the settlement evaluation; iii) the origin of the high frequency motion oscillations to simple sinusoidal input motions; all with respect to potential improvements in the formulation of the elastic behaviour of the constitutive model in the future.

Analytical solution for the kinematic response of end-bearing piles subjected to SH waves in a homogeneous layer by an improved beam-foundation model

This paper presents an analytical solution for evaluating kinematic response in piles subjected to shear waves. The proposed model treats the pile as a Timoshenko beam supported by a two parameter Winkler foundation, capturing both transverse and rotational ground reactions. Validation against both analytical and numerical solutions from the literature, particularly 3D finite element models, shows very good agreement. The proposed model generalizes different solutions currently applied in practice, covering various pile slenderness ratios and ground conditions. This approach addresses limitations in existing Euler-Bernoulli beam resting on Winkler or Vlasov-Pasternak foundation models, by incorporating shear distortions in the structure and ground friction at the interface. Shear stresses induced by the rotational springs are found to significantly influence the kinematic factors, as well as bending and, particularly, shear forces. Finally, simplified expressions for kinematic interaction factors and forces are provided for expedited analyses of practical engineering problems.

Mechanism of quantum chaos in molecular nonadiabatic electron dynamics.

The quantum nuclear kinematic interactions with electrons (or nonadiabatic interactions) are the inherent driving force that possibly causes a mixture of the adiabatic electronic states in molecules. Particularly in systems whose electron wavepackets lie in a densely quasi-degenerate electronic-state manifold where many-dimensional and many-state nonadiabatic interactions last continually, we have found before that those extensive mixings can lead to a quantum electronic-state chaos [K. Takatsuka and Y. Arasaki, J. Chem. Phys. 159, 074110 (2023)]. This chaos of electron dynamics is a new kind yet generic. This Communication identifies the mathematical/physical mechanism of this class of chaos by means of the collective coordinate analysis of the nonadiabatic interactions, along with the numerical applications to excited states of boron clusters. Some physical consequences of the present chaos are also discussed.

3D Numerical Modeling of the Inertial and Kinematic Interactions of Inclined Pile Groups in Liquefiable Soils

3D Numerical Modeling of the Inertial and Kinematic Interactions of Inclined Pile Groups in Liquefiable Soils

Seismic response of jacket-supported offshore wind turbines for different operational modes considering earthquake directionality

This study aims to analyse how jacket-supported OWTs functioning in three different operational modes (power production, emergency shutdown and parked mode) respond to seismic actions when subject to different incoming wind directions and ground motion shaking directions. To do so, the seismic response of the NREL 5MW OWT founded on the OC4 jacket substructure is simulated using an OpenFAST model that includes multi-support seismic input, soil–structure interaction and kinematic interaction. The impact of the working conditions and of the directionality of the loads on the jacket substructure is analysed and discussed. The tower top accelerations and displacements are examined for different sets of cases, and the seismic response of the jacket is studied in terms of internal forces and von Mises stresses along the different levels of the substructure. The results show, and quantify, the relevance of considering the different operational modes for a correct design of the substructure and of the foundation. The maximum structural stresses within the jacket substructure appear almost always in power production, with the exception of the top part of the legs, where higher stresses arise during emergency shutdown in several cases.

Comparative study of the influence of kinematic interaction on the seismic response of monopile and jacket supported offshore wind turbines

Comparative study of the influence of kinematic interaction on the seismic response of monopile and jacket supported offshore wind turbines

Non-linear behaviour of soil–pile interaction phenomena and its effect on the seismic response of OWT pile foundations. Validity range of a linear approach through non-degraded soil properties

The effect of non-linear and inelastic behaviour of the soil–pile interaction on the seismic response of offshore wind turbine pile foundations embedded in sandy soils is analysed. For this purpose, the responses obtained assuming three different Beam on Dynamic Winkler Foundation (BDWF) models are compared: a Plastic Non-Linear Model (PNLM), an Elastic Non-Linear Model (ENLM) and a simple elastic linear model with non-degraded properties of soil (NDLM). The influence of non-linearity and plasticity assumption is studied by evaluating the effects of the kinematic and inertial interaction within soil–pile interaction. Two soil stiffness levels are analysed: very loose and medium dense sand. The seismic response under ten earthquakes is computed in terms of mean envelopes of internal forces along the pile length. The non-linearity and inelastic influence of soil–pile interaction is quantified by means of relative differences with respect to the linear elastic model. Results show that the non-linear and inelastic models acquire relevance when the contribution of the inertial interaction dominates, leading to lower maximum responses than the linear elastic model. If the inertial interaction is not significantly activated, similar results between the three models are obtained, being the linear elastic model enough to reproduce the soil–pile dynamic interaction.

The effect of dopaminergic treatment on whole body kinematics explored through network theory

Three-dimensional motion analysis represents a quantitative approach to assess spatio-temporal and kinematic changes in health and disease. However, these parameters provide only segmental information, discarding minor changes of complex whole body kinematics characterizing physiological and/or pathological conditions. We aimed to assess how levodopa intake affects the whole body, analyzing the kinematic interactions during gait in Parkinson’s disease (PD) through network theory which assess the relationships between elements of a system. To this end, we analysed gait data of 23 people with PD applying network theory to the acceleration kinematic data of 21 markers placed on participants’ body landmarks. We obtained a matrix of kinematic interactions (i.e., the kinectome) for each participant, before and after the levodopa intake, we performed a topological analysis to evaluate the large-scale interactions among body elements, and a multilinear regression analysis to verify whether the kinectome’s topology could predict the clinical variations induced by levodopa. We found that, following levodopa intake, patients with PD showed less trunk and head synchronization (p-head = 0.048; p-7th cervical vertebrae = 0.032; p-10th thoracic vertebrae = 0.006) and an improved upper-lower limbs synchronization (elbows right, p = 0.002; left, p = 0.005), (wrists right, p = 0.003; left, p = 0.002; knees right, p = 0.003; left, p = 0.039) proportional to the UPDRS-III scores. These results may be attributable to the reduction of rigidity, following pharmacological treatment.

Experimental study of the kinematic interaction between a cohesive soil and a group of rigid inclusions through dynamic centrifuge tests

Experimental study of the kinematic interaction between a cohesive soil and a group of rigid inclusions through dynamic centrifuge tests

Efficient modelling of progressive damage due to quasi-static indentation on multidirectional laminates by a mesh orientation independent kinematically enriched continuum damage model

This work proposes a computationally efficient high-fidelity modelling framework for analysis of damage in composites subjected to quasi-static indentation. A ply-by-ply modelling approach is adopted, and a new semi-discrete continuum damage model is used for intra-ply cracking that allows for cracks to grow independent of the ply mesh pattern. This feature greatly simplifies the meshing effort since the requirement of a ply-oriented mesh and imposition of tie constraints at mesh-mismatched ply interfaces is eliminated. The model is further enhanced to realise kinematic interactions between the cracked and uncracked material domains at the constitutive level. Inter-ply delamination is simulated using cohesive elements. Through a challenging problem of static indentation on a quasi-isotropic laminate, it is shown that the model can capture solution-dependent multiple discrete ply cracks and detailed crack-delamination interaction, but with reduced computational time and complexity, compared to a reference model with ply-oriented mesh and pre-seeded cracks at known locations.

Discrete Element Modelling of uplift of rigid pipes deeply buried in dense sand

This paper presents a numerical methodology based on the Discrete Element Method developed for the efficient modelling of kinematic granular soil-pipe interaction at large deformations. The methodology is based on a robust Bayesian procedure for calibrating micromechanical contact parameters using standard triaxial compression tests, does not rely on the back-analysis of physical model experiments, and produces accurate “blind” predictions of independent experimental measurements. The latter is demonstrated by extensively validating DEM models against measurements obtained from direct shear tests on sand performed during this study and published measurements from 1-g physical model experiments of uplift of rigid pipes buried in dense sand. In addition, we introduce different approaches that allow efficient modelling of deeply buried pipes, and we employ the methodology to investigate how the reaction from sand to rigid pipe uplift varies as the pipe embedment depth increases. Detailed numerical predictions provide insights into the “flow-around” failure mechanism that develops around the deeply buried pipes and on the existence of a critical embedment depth, beyond which the normalised reaction does not further increase with increasing pipe embedment. The outcomes of this study are applicable to the stress analysis of deeply buried pipes in practice and to the modelling of a variety of problems relevant to rigid objects buried deeply in granular soil.

Influence of wind and seismic ground motion directionality on the dynamic response of four-legged jacket-supported Offshore Wind Turbines

This paper aims at investigating the influence of the direction of wind and seismic ground motion on the structural response of four-legged jacket support substructures for bottom-fixed Offshore Wind Turbines located in areas with non-negligible seismic risk. To do that, a parametric analysis that considers thirteen seismic shaking directions, seven wind directions and four earthquake records is carried out. The results are presented in terms of accelerations, axial forces, bending moments and shear forces in the jacket substructure. The NREL 5 MW wind turbine supported on the jacket designed for the phase I of the OC4 project is considered. The response of the system is simulated using an OpenFAST model that takes into account multi-support seismic input, soil–structure interaction and kinematic interaction. The results show that load combinations with aligned wind and ground motion directions are never the worst-case scenario. On the contrary, the largest accelerations are found when the shaking direction acts along the side-to-side direction, and the most significant internal forces are usually found when the ground motion is aligned with one of the diagonals of the base of the jacket and not aligned with the wind direction. The paper also discusses the specific ranges of the angle of misalignment between wind and seismic shaking directions within which the maximum internal forces are expected to be found.

Design, kinematic and fluid-structure interaction analysis of a morphing wing

The application of morphing wing enables vehicles to show better aerodynamic performance in various flight conditions. This article proposes a modular bilateral triangular pyramid (BTP) unit-based morphing wing skeleton (MWS) mechanism that may achieve continuous variable span-wise bend, span-wise twist, and sweep. A lockable morphing (LM) unit with the BTP unit is designed. Based on the Denavit–Hartenberg coordinate method and motion influence coefficient method, the kinematics of MWS mechanism is conducted. The theoretical models of the kinematic characteristics of the MWS mechanism during the three morphing patterns are obtained. The kinematic simulation models of three morphing configurations of the MWS mechanism are performed. The driving speed ratio of the linear actuator of span-wise bend and twist is analyzed during the twisting phase, and the analysis shows that there be a speed ratio minimizes the coupling bend angle. By comparing the results between the theoretical and simulation models, the accuracies of kinematic theoretical models under different morphing configurations are verified. At last, this article conducted a two-way fluid-structure interaction (FSI) analysis of morphing wing to obtain the influence of aerodynamic load on the flexible skin and skeleton mechanism, as well as the influence of structural deformation on the aerodynamic characteristics. Results show that the initial and swept states have the greatest impact on the out of plane bearing capacity of the flexible skin. In addition, the out-of-plane bulging deformation located at the trailing edge of the flexible skin is beneficial for improving aerodynamic performance, while the protrusion located at the leading edge increases air resistance. These findings provide important theoretical basis for the application of the MWS mechanism.

Numerical Investigation of the Pile–Soil Interaction Problem under Dynamic Loads

One of the most important problems of geotechnical engineering is the design of pile foundations. Piles are generally designed for vertical and horizontal static loads. However, it is important to design piles against dynamic loads in regions with high seismicity. This study verified a centrifuge experiment obtained from the literature with a finite element program. With the kinematic interaction analyses performed for this purpose, the effect of parameters such as layered soil, groundwater, pile stiffness, and earthquake acceleration were investigated numerically. According to the results obtained, it was understood that the earthquake magnitude is the most important parameter in kinematic interaction analyses. In addition, in layered soil conditions, the fact that 75% of the pile length is in the weak soil creates the most unfavorable situation. It was observed that pile stiffness and groundwater level also have certain effects on the kinematic interaction.

Effects of kinematic and inertial interaction on seismic responses of pile-structure system in liquefiable and non-liquefiable deposits

Numerical simulation models for pile group-superstructure in liquefiable and non-liquefiable sites were established. The validity and reliability of the numerical model are verified by the shaking table test results. Based on the cross-correlation analysis of superstructure acceleration-pile bending moment and soil displacement-pile bending moment obtained from the tests, the coupling law of kinematic and inertial interaction and its influence on pile failure modes were discussed combined with the numerical simulation results. The results shown that the effect of kinematic interaction on piles were greater than that of inertial interaction in both types of sites, but coupling mechanisms of kinematic and inertial interaction were different. For the liquefiable site scenario, the middle part of piles was prone to bending failure and the kinematic interaction was the main reason for it. For the non-liquefiable site scenario, the inertial interaction had an obvious influence on the pile failure occurred at the pile top. The results of parameter analysis shown that the mass of the superstructure was the most important parameter of inertial interaction in the liquefiable site. Parameters of inertial interaction would affect the vibration of the superstructure in the non-liquefiable site, but the influence on pile bending moments was not obvious.

An analytical solution for the filtering effect of piles in two-layer soil

The aim of this work is to investigate the kinematic response of a floating pile (either free- or fixed-head) embedded in a two-layer soil subjected to upward-propagating seismic waves. Closed form analytical solutions are provided for the kinematic interaction factors, based on a Beam-on-Dynamic-Winkler-foundation (BDWF) model properly adjusted for the problem at hand. For the fixed-head pile case, a simplified solution to assess the pile-to-soil acceleration ratio is provided adopting the concept of average soil motion over an effective pile length. The proposed solutions compare well with rigorous elastodynamic Finite-Element analysis. Insight is given into the interpretation of the mechanisms regulating the reduction of design spectra as function of structural period. Finally, as an outcome of a wide parametric study, ready-to-use formulae are proposed for a rapid assessment of the pile-induced spectral reduction.

Kirigami layer jamming

Variable stiffness materials bridge the desirable qualities of soft and rigid robotic components, forming the basis of new machines that contextually adapt their structural properties. Recent developments have led to the creation of jamming materials: Collections of media that undergo pressure-dependent kinematic and frictional interactions to radically, rapidly, and reversibly change in stiffness. Among the types of jamming, laminar jamming harnesses an ensemble of sheets for stiffness changes. Most implementations of laminar jamming employ unaltered, continuous sheets, though the vast design space of mechanical anisotropy programmed via structured cuts invites a new jamming paradigm: kirigami laminar jamming. Through analytical, experimental, and numerical studies, we show how intentional topological augmentation of laminar jamming sheets through shell, void, and cut geometric primitives can elicit bespoke mechanical responses. In particular, we optimize jamming specimens to enhance the jammed to unjammed flexural stiffness ratio across a range of deflections, which unlocks new move-and-hold capabilities. We also demonstrate pressure-induced shape morphing and both sharp-edged and doubly-curved surface matching with kirigami patterns. Results hold broad significance for robotics, morphing structures, and the systematic design of variable stiffness materials.

Dynamic Soil-Structure Interaction Through 2-D Site-Specific Response Analysis

Seismic response of structures involved soil-structure-interaction (SSI) that need to consider both inertial and kinematic interaction. Many underground SSI has been developed such as modelling the structures and soils as continuum with seismic load simplified as pseudo-static or static equivalent. More recent and more realistic SSI model consider non-linear time-history analysis in the form of 2-D site-specific response analysis (SSRA), in which both inertial and kinematic interaction in combination with non-linear soil model, as well as time-history ground-motions are simulated. This paper presents simplified pseudo-static soil-structure interaction finite-element (FE) response of underground box-station structure under prescribed maximum strain displacement as resulted from 1-D site-specific response analysis under various ground-motions characteristics of subduction and shallow crustal earthquakes. More complex model of SSI system of basement is also presented. This basement SSI model incorporates non-linear time-history analysis with dynamic soil properties considered through 2-D SSRA simulating seismic wave propagation from reference base-rock to ground surface. Various base-rock seismic ground-motions are simulated from results of de-aggregation analysis from probabilistic seismic hazard analysis considering both subduction and shallow crustal earthquakes scaled at various ground-motion periods. The analysis adopts dynamic soil model with non-linear modulus and damping using FLAC computer program.