Principle Of Displacement Research Articles

A novel colorimetric and fluorometric dual-signal identification of crude baijiu based on La-CDs

The correct classification of strong-flavored crude baijiu affects its quality and overall standard and is crucial for the intelligent development of the baijiu industry. In this work, we developed a novel optical sensing array using lanthanum-doped carbon dots (La-CDs). Using La-CDs with three metal complex dyes—chromium black T, alizarin red, and dimethylphenol orange—we were able to detect organic acids and tannic acid (TA) in crude baijiu in a way that was both colorimetric and fluorescent for the first time. Based on the indicator displacement (IDA) principle, organic acids competitively replace the dyes' binding sites on La3+, causing the dye colors to change to varying degrees. TA quenches the fluorescence of quantum dots through an internal filtering effect. We analyzed the data using pattern recognition algorithms such as HCA, PCA, and LDA, successfully classifying and identifying 16 types of strong-flavored crude baijiu, which included 10 types of carboxylic acids and various grades. In blind tests of 32 crude baijiu samples, the colorimetric method achieved a 94 % accuracy rate, while the fluorescence method achieved 100 %. The sensor demonstrates significant advantages in response speed.

Research on Decision-Making and Control Technology for Hydraulic Supports Based on Digital Twins

To further enhance the intelligent construction of coal mines and improve the control accuracy of hydraulic support displacement straightness, a digital twin control method for hydraulic support displacement has been proposed. First, a dataset related to hydraulic support is established, and a ridge regression prediction model is developed to achieve digital twin-based displacement decision analysis. Next, by analyzing the mechanical structure and displacement principles of the hydraulic supports, a hydraulic cylinder mathematics model is established, leading to the state-space representation of the controlled object. This study focuses on error control during the multi-agent operation of the hydraulic supports, designing a corresponding controller and using discretization methods to verify the consistency of output displacement between followers and leaders. Finally, simulation experiments based on the digital twin model of hydraulic supports are conducted, validating that the hydraulic supports can be controlled in formation according to actual production requirements. The digital twin control method enables the precise adaptive displacement control of hydraulic supports and provides valuable insights for the intelligent construction of mining faces.

Foam density measurement using a 3D scanner

In this work, we used a 3D scanner for the volume measurement of foamed samples, a long-standing problem in the density evaluation of foams. The 3D scanning density measurement method can be selected as an alternative to or in combination with well-established, classical methods that involve the use of instruments like a caliper, a pycnometer, or other devices based on displacement or flotation principles. In particular, the classical methods show some limitations when the foamed sample geometry is irregular, when the polymer is highly hygroscopic, and when it has open porosities. We have tested numerous foamed samples of different sizes, shapes, densities, materials, and morphologies. We utilized different 3D scanner configurations for their volume measurement and compared the results with geometrical and displacement methods, when possible. Results showed that the proposed method is highly accurate, reproducible, and simple, although some specific precautions should be put in place to avoid misinterpretation by the shape-reconstructing software.

Basic Principles of Deformed Objects with Methods of Analytical Mechanics

Analytical mechanics is the most fundamental discipline in this field. The basic principles of analytical mechanics should also be applicable to deformed objects. However, the virtual displacement principle proposed by analytical mechanics is only applicable to particle systems and rigid body systems, and not to general deformed objects. In this study, the basic principle, which includes the virtual displacement principle and d’Alembert–Lagrange principle (also called the virtual displacement principle of dynamics), of general deformed objects (such as, elastic, plastic, elasto-plastic, and flexible objects) is derived using analytical mechanics. First of all, according to the method of analytical mechanics, the external force, internal force, constraint reaction force and elastic recovery force of the deformed object system under the equilibrium state are analyzed, and the concepts of virtual displacement, ideal constraint and virtual work are introduced, and the virtual displacement principle (also called virtual work principle) of deformed objects is proposed; secondly, vector form, coordinate component form and generalized coordinate form of generalized virtual displacement principle of deformed object are given; thirdly, Introduce inertial force and use analytical mechanics to derive the d’Alembert–Lagrange principle of dynamic systems; fourthly, as application of the principle, the virtual displacement principle of deformed objects in plane polar coordinate system, space cylindrical coordinate system and spherical coordinate system are given; fifthly, the constitutive relationship between the gravitational strain of elastic–plastic materials was introduced, and an example of the application of the d'Alembert–Lagrange principle in elastic–plastic objects was given; finally, a brief conclusion is drawn. This study unifies the virtual displacement principle of elastic objects, plastic, elastoplastics, deformed object systems and rigid object systems using the basic analytical mechanics method. This is a basic principle for dealing with the static problems of deformed objects. This work also lays the foundation for further study of the dynamics of deformed object systems.

Computer Simulation for Determination of Critical Buckling Temperatures of Sandwich Microplates with Cellular Core and CNT-RC Piezoelectric Patches via MSGT

This study introduces a computational simulation which leads to obtaining the critical buckling temperatures of a sandwich microplate which is modeled based on the modified strain gradient theory. This theory includes three material length scale parameters. The core of the microstructure is made from cellular materials which is treated with piezoelectric carbon nanotubes-reinforced composite patches. An advanced trigonometric hyperbolic shear deformation theory, eliminating the need for shear correction factors, is employed to analyze the microstructure. Thickness-dependent variations in structural characteristics are observed based on predefined functions. The equilibrium equations are derived using the virtual displacement principle. Fourier series functions provide an analytical way of solving these equations. The findings are verified by comparison with earlier research that was published and used fewer complex combinations. The study looks at how several important factors affect the structure’s reaction to thermal buckling.

Non-linear behavior of functionally graded elastoplastic beam under torsion

The torsional behavior of beams graded in one and two directions under large displacements and angular deformations was analyzed using the power law and sinusoidal functions. Functionally graded material is elastoplastic, consisting of ceramic and metal. A nonlinear finite element method with isoparametric hexahedral elements was used. The finite element formulation was made using the updated Lagrangian formulation based on the virtual displacement principle. An iterative solution using Newton-Raphson and updated Newton-Raphson methods was used to solve the nonlinear equation system. The propagation of the plastic zone was calculated based on the flow theory of plasticity. Elastoplastic behavior and effective material properties were determined according to the TTO model. Numerical investigations have shown that functionally graded beams behave quite differently from homogeneous beams under torsion. Yielding of the material starts at the outer boundaries of the section of the homogeneous beams, and the plastic zone propagates symmetrically. On the other hand, yielding and propagation of plastic zones tend to shift to regions with more ceramic volume with higher effective Young modulus in functionally graded beams. Unlike homogeneous beams, the largest shear stresses can occur within the section rather than at the outer boundaries of the section. In beams graded from ceramic to metal using the power law, the section moves along the transverse direction in addition to the rotation. This transverse displacement occurs in the grading direction, and its magnitude is about 3% of the thickness at 12.5° rotation angle. Also, the shear stresses are not zero in the section's midpoint. The effects of material distribution on displacements, stresses, and plastic zone propagation were examined, and essential points were reported.

In-Plane Vibrations of Deep Sandwich Arches with Different End Conditions Based on a Logarithmic Shear Deformation Theory

This paper deals with the vibrational frequencies of deep sandwich arches to enhance their application domain and possibly use them for energy harvesting. The circular arch with porous nanocomposite core and titanium alloy face sheets having different end conditions is numerically analyzed. The middle core of the sandwich arch is made of a six-layered porous aluminum reinforced with graphene nanoplatelets. The kinematic equations are formulated in this study based on the higher-order shear deformation theory using a logarithmic function of radius. The effective properties of the nanocomposite media are modeled by employing the Halpin–Tsai modified rule. The equations of motion are determined by applying the principle of virtual displacement. The partial differential equations are reduced using the generalized differential quadrature technique to solving an algebraic eigenvalue problem. Novel numerical results are given to show the effects of geometrical parameters, material properties, and boundary conditions on the vibrations of deep sandwich arch.

Geometric Nonlinear Analysis of Angle Section Elements Based on Updated Lagrangian Formulation and Rigid Body Rule

Angle cross-section members are widely used in various transmission towers owing to their convenient connections, easy availability, simple production processes, and high efficiency. Such members are very susceptible to nonlinear behavior when subjected to abnormal or extreme loads. In this work, a new geometric stiffness matrix for thin-walled steel members with an angle cross-section is derived based on the principle of virtual displacement, rigid body rule and updated Lagrangian equations. The generalized displacement control (GDC) method is employed to deal with the issues of non-convergence at the extreme value point and rebound point in the geometric nonlinear analysis, which offers clear physical meaning and can adjust the loading direction. The geometric and the traditional elastic stiffness matrices derived in this work are applied during the prediction phase, while only the traditional elastic stiffness matrix is used in the correction phase. The comparisons of the results obtained by the proposed method with those in the previous literature and ANSYS numerical solutions show that the proposed method is sufficient to ensure the accuracy and applicability for addressing the structural geometrically nonlinear issues.

Analysis of transverse constraint force mechanics of anchor rods based on higher order theory

Abstract Research on the mechanical properties of transverse constraint force of anchor support under different loads can help to improve work safety. In this paper, based on the higher-order shear deformation theory, the higher-order whole-local theory of anchor rods is established with full consideration of the transverse normal strain. The geometric and physical equations in the intrinsic relationship are given for the wet thermodynamic behavior of anchor rods’ transverse restraining force. The equilibrium equations of the whole-local are constructed by combining them with the principle of virtual displacement. The analytical solution of the anchor core material was calculated by applying Navier’s method. The boundary displacement conditions of the anchor core material were solved. The anchor core material was modeled by combining it with ABAQUS finite element software. The mechanical analysis was carried out from the two perspectives of the buckling problem under thermal load and the parameter change of the transverse restraining force, respectively. It was found that when the thickness of the anchor bar increased from 20 mm to 50 mm, the radial displacement of the upper layer decreased by 52.95%, and there was no significant change in the positive stress at the upper and lower interfaces. The peak value of the upper interface shear stress decreases significantly from 0.55MPa to −1.41MPa when the anchor laying method is changed from a single layer to four layers. The combination of higher-order theory with ABAQUS software can effectively analyze the change of transverse constraint force of the anchor support, which can help improve its safety.

Rapid high-throughput isolation and purification of chicken myoblasts based on deterministic lateral displacement microfluidic chips.

Myoblasts are defined as stem cells containing skeletal muscle cell precursors. However, there are some challenges associated with the purification of myoblast samples, including long culture times and ease of bacterial contamination. In this study, we propose a microfluidic myoblast cell enrichment and purification platform based on the principle of deterministic lateral displacement (DLD). To achieve this, we designed a DLD chip with three outlets and tested it on 11-day-old (E11) Wenchang chicken pectoral muscle tissue. A cell suspension was prepared using the collagenase method, pretreated, and then passed into the designed DLD chip for myoblast enrichment and purification. In this study, the number of myoblasts and the diameter of myoblasts increased slowly before E9, and the diameter of myofibers decreased and the number of myofibers increased rapidly after E9. The period when the muscle fibers are most numerous is on the E12, and the period when the diameter of the muscle fibers begins to increase again after reaching its lowest point is also on the E12. After E12, the diameter of the muscle fibers increased and the number of muscle fibers decreased. At E12, myoblasts clustered and fused, and the proliferation of myoblasts was greatly reduced. E12 is both intact myoblasts and the most vigorous proliferation period, so the best time to determine isolation is E12. We attained a myoblast cell recovery rate of 80%, a target outlet collection purity of 99%, and a chip throughput of 50 μ m/min. In this paper, we innovate chips design according to specific geometries and functions for Wenchang chicken pectoral muscle tissue, so as to optimize the isolation and purification process of myoblasts. This study provides a novel and effective method for the isolation and purification of skeletal muscle myoblasts.

A unified buckling formulation for linear and nonlinear analysis of laminated plates using penalty based [formula omitted] FEM-HSDT model

In this paper, the effect of pre-buckling boundary conditions and the type of nonlinearity for stress stiffening used in different linear and nonlinear buckling approaches is studied for laminated composite plates. The study is conducted using a C0 finite element (FE) plate model, employing a unified C1 higher-order shear deformation theory (HSDT). The set of governing equations is derived using the principle of virtual displacement and solved using the tangent-based arc-length method in conjunction with a simple branch switching technique. The performance of the present C0 FE model is assessed through a validation exercise and comparison with results obtained via the use of ANSYS and, for linear analysis, Navier solution, as well as solutions available in the literature. The influence of the different in-plane loads, boundary conditions, side-to-thickness ratio, fiber orientation, types of imperfection and penalty stiffness matrix are also examined. The results show that the same boundary conditions must be utilized in both pre-buckling and linear eigenvalue analyses for accurate and realistic predictions of critical buckling loads, as confirmed from the nonlinear buckling analyses. Furthermore, the critical buckling loads obtained using Green–Lagrange nonlinearity are observed to be more conservative than those obtained using von Kármán nonlinearity. The nonlinear buckling approach is a generalized approach while the nonlinear eigenvalue approach has a limited range of application.

Integrated optimization of the in-wheel motor driving system considering the ride comfort of the electric vehicle under multiple operating conditions

In this paper, a multi-objective optimization scheme integrating structural parameters with control parameters is proposed to address the adverse effects of an unbalanced magnetic pull of the wheel motor on vehicle dynamics. Firstly, the unbalanced magnetic pull under the air gap eccentricity of a switched reluctance motor is analyzed using both Maxwell’s stress method and the principle of virtual displacement. Then, a current chopper control strategy for the in-wheel motor is developed, and the influence of relevant control parameters on the output characteristics of the motor driving system under different driving conditions is discussed. Finally, a multi-objective optimization model of a motor under multiple operating conditions is developed with the aid of multidisciplinary optimization software. Integration of structural and control parameters for optimization. The results show that the motor design parameters determined by the integrated optimization scheme can improve the vehicle’s response characteristics under a wide range of operating conditions. In particular, the negative effect caused by an unbalanced magnetic pull during the operation of the vehicle is greatly suppressed.

Research progress and application of deep in-situ condition preserved coring and testing

With the depletion of shallow resources, the exploration of deep earth resources has become a global strategy. The study of the different patterns in the physical mechanical properties of rocks at different occurrence depths is the basis for exploring deep into the earth, with the core and premise being the acquisition and testing of deep in-situ core specimens. Based on the original idea of deep in-situ condition preserved coring (ICP-Coring) and testing, combined with theoretical modeling, numerical analysis, test platform development, indoor testing and engineering application, the principles and technologies of deep ICP-Coring are developed. This principle and technology consists of five parts: in-situ pressure-preserved coring (IPP-Coring), in-situ substance-preserved coring (ISP-Coring), in-situ temperature-preserved coring (ITP-Coring), in-situ light-preserved coring (ILP-Coring), and in-situ moisture-preserved coring (IMP-Coring). The theory and technology of temperature and pressure reconstruction at different occurrence depths and in different environments are proposed, and prototype trial production was completed by following the principle of displacement and tests based on the in-situ reconstructed environment. The notable advances are as follows: (1) Deep in-situ coring system: A pressure-preserved controller with an ultimate bearing capacity greater than 140 MPa, high-performance (temperature-resistant, pressure-resistant, and low thermally conductive) temperature-preserved materials, an active temperature control system, and high-barrier quality-preserved membrane materials were developed; a deep ICP-Coring capacity calibration platform was independently developed, a deep in-situ coring technology system was developed, and the acquisition of deep in-situ cores was realized. (2) In-situ storage displacement system: Following the dual-circuit hydraulic design idea, a single-drive source push-pull composite grabbing mechanism was designed; the design of the overall structure for the deep in-situ displacement storage system and ultrahigh pressure cabin structure was completed, which could realize docking the coring device and core displacement in the in-situ reconstructed environment. (3) Test analysis system: A noncontact acoustic-electric-magnetic test system was developed under the in-situ reconstructed environment, and the errors between the test results and traditional contact test results were mostly less than 10%; a detachable deep in-situ core true triaxial test system was developed, which could perform loading tests for deep in-situ cores. The relevant technological achievements were successfully applied to the exploration and development of deep resources, such as deep mines, deep-sea natural gas hydrates, and deep oil and gas. The research results provide technical and equipment support for the construction of a theoretical system for deep in-situ rock mechanics, the development of deep earth resources and energy, and the scientific exploration of different layers and occurrence depths (deep and ultradeep) of the Earth.

On the Static Instability of FG-GNP-Reinforced Composite Cylindrical Shells Under Thermo-Mechanical Loading

The nonlinear buckling response of laminated composite cylindrical shells reinforced with graphene nanoplatelets (GNPs) is studied in this paper. The functionally graded (FG) shell reinforced by GNPs is analytically studied under external pressure and uniform temperature rise loadings. It is also assumed that the GNP-reinforced laminated composite shell is in contact with an elastic foundation. Various types of profiles are employed for the GNP distribution patterns in the shell thickness including 10 nanocomposite layers. The nonlinear strain-displacement relations of the shallow cylindrical panel are established utilizing the third-order shear deformation shell theory. Governing equilibrium equations of the laminated GNP-reinforced composite shell are formulated employing the principle of virtual displacement. The coupled system of nonlinear differential equations is solved analytically for the hinged–hinged and fixed–fixed boundaries of the shell using a perturbation-based technique. Correctness of presented formulations and obtained solutions is proved by comparisons with results from previous studies for an isotropic cylindrical shell. Novel numerical results reveal that the material properties, geometrical characteristics and load parameters significantly affect on the buckling behavior of laminated composite cylindrical shells.

Research on Identifying Robot Collision Points in Human–Robot Collaboration Based on Force Method Principle Solving

After years of more rigid and conventional production processes, the traditional manufacturing industry has been moving toward flexible manufacturing and intelligent manufacturing in recent years. After more than half a century of development, robotics has penetrated into all aspects of human production and life, bringing significant changes to the development of human society. At the same time, the key technology of human–machine cooperative operation has become a research hotspot, and how to realize a human–machine integrated safety system has attracted attention. Human–machine integration means that humans and robots can work in the same natural space, coordinating closely and interacting naturally. To realize real human–robot integration under human–robot cooperative operation, the good judgment of intentional interaction and accidental collision and the detection of collision joints and collision points when accidental collision occurs are the key points. In this paper, we propose a method to identify the collision joints by detecting real-time current changes in each joint of the robot and solve the collision point location information of the collision joints through the principle of virtual displacement and the principle of force method using the force sensor data installed at the base of the robot as the known condition. The results show that the proposed method of identifying the collision joints using changes in joint current and then establishing a collision detection algorithm to solve the collision point location is correct and reliable.

Nonlinear Lyapunov-based control of a misaligned heteropolar magnetic bearing system

ABSTRACT The dynamic behavior of an active magnetic bearing (AMB) mounted rotor was investigated through an analytical study conducted as part of this research work. A biased AMB model was developed, in which six electromagnets were supplied with a bias current I0 , and their respective control currents. The magnetic load was obtained through a differentiated driving mode based on the virtual displacement principle. Motion equations were formulated, and simulations were performed to investigate the dynamic response of the misaligned AMB mounted on a high-speed rotor, considering rigid body motion, elastic motion, gyroscopic effect, shear deformation effect, and internal damping. Subsequently, a nonlinear novel direct Lyapunov-based controller derived from an energetic approach was applied and compared to an optimal regulator based on Hamilton-Jacobi-Bellman (HJB) equations. The Linear Quadratic Riccati (LQR) method required less energy, as expected, but the Lyapunov method was more efficient and demonstrated its ability to asymptotically control the plant instability as well as the misalignment effect. Finally, the method was applied to a milling machine spindle, and the controller was still able not only to handle the cutting forces generating disturbances but also to overcome the defect effect without any oscillation.

Experimental investigation on plastic hinge length of RC round-ended hollow columns with a variable section

In the ductile design, it is an essential task to accurately estimate the equivalent plastic hinge length of a reinforced concrete (RC) column. The plastic behavior of a RC hollow column is influenced significantly by tension shift and bond-slip according to the test results, which hasn’t yet received adequate attention in the existing models of equivalent plastic hinge in the literatures. Few publications and even no explicit provision in the current codes provide the method to compute the plastic hinge of hollow RC columns, especially those with a variable section. To bridge this knowledge gap, in this study, based on the equivalent principle of plastic displacement, an innovative formula of equivalent plastic hinge length is derived for the hollow columns, which considers both the effects of plastic tension shift and bond-slip based upon the authors’ previous research on solid columns. The quasi-static tests on two rectangular and two round-ended hollow columns were conducted to calibrate the undetermined parameters of the proposed formula. The accuracy and applicability of the proposed formula were then investigated based on the available test results of 30 rectangular and 3 round-ended hollow columns in literature. The results show that different slip behavior leads to distinct plastic deformation between these two types of hollow columns. Compared to the rectangular columns with a uniform section, the plastic hinge length of round-ended columns is longer due to the presence of the bottom solid segment, chamfer, and variable section. For both types of hollow columns, the equivalent plastic hinge region increases with the specimen length, section height, and strain penetration. The comparison suggests that the proposed formula is more appropriate to calculate the plastic hinge length of hollow columns with a uniform or variable section than the existing models.

Thermo-Electro-Mechanical Analysis of Micropolar FGP Cylindrical Shell Covered with Piezoelectric Actuator Layers

An investigation is performed in this paper to analyze the nonlinear thermo-electro-mechanical response of long sandwich cylindrical shells with functionally graded porous (FGP) core and thin piezoelectric actuator layers. The FGP core of the sandwich shell is assumed to be temperature- and microstructure-dependent. It is assumed that the sandwich shell is subjected to uniform lateral pressure loading in a thermo-electrical environment. The equilibrium equations of the shell with infinite length are established with the aid of the virtual displacement principle and von Kármán kinematic assumptions. The governing equations are obtained in terms of displacement components based on the first-order shear deformation model of shallow cylindrical shells and the modified couple stress theory. These nonlinear differential equations are analytically solved for a sandwich shell having both the simply-supported and clamped–clamped edge conditions by employing a two-step perturbation technique. Analytical closed-form solutions are determined as a relationship including the load parameter and the mid-span deflection. The comparison examples are made with the existing results in the literature for a simple functionally graded shell, where good agreement is obtained. It is shown that the nonlinear response of the sandwich shell is highly dependent upon the temperature variation, power law index, porosity coefficient, couple stress parameter, piezoelectric layers, and geometrical parameters of the shell.

An extended ordinary state-based peridynamic model for nonlinear deformation and fracture

Peridynamic is a promising nonlocal continuum theory that reconstructs the equations of motion of solid mechanics using spatial integral equations, rendering it suitable for describing objects with discontinuities such as cracks. In this study, a novel extended ordinary state-based peridynamic model was developed for nonlinear deformation and fracture analysis, which established a general relationship with continuum-based parameters and permitted the selection of different influence functions. Based on the principle of virtual displacement, the complete derivations of the peridynamic parameters were presented for two and three-dimensional conditions. After that, the specific numerical scheme and algorithm implementation were summarized. The capability and accuracy of the proposed nonlinear model were verified by comparing with the experimental and finite element simulation results. Finally, several other numerical examples were provided to further demonstrate the applicability and robustness of the proposed model and its implementation.

Stability analysis of hybrid laminated cylindrical shells reinforced with shape memory fibers

Laminated composite structures are widely used in various industries. Body and cape of high-speed flight vehicles are exposed to aerodynamic heating so that causes thermal buckling and dynamic instability. Shape memory alloys (SMAs) have extraordinary mechanical and physical properties which made them suitable for application in laminated structures. In this paper, stability analysis of hybrid laminated cylindrical shells reinforced with SMA fibers is investigated. Utilizing the principle of virtual displacement, governing equations and associated boundary conditions are determined based on the first-order shear deformation theory of shells considering Von- Kármán form of geometrical non-linearity and Love's first approximation. Material properties of SMA fibers and composite vary due to temperature. Variation of thermo-mechanical properties for SMA fibers due to uniform change of temperature are determined through the one-dimensional form of Brinson's constitutive law. Also, different types of loading conditions consist of axial load, pure lateral pressure and hydrostatic pressure are considered. Eventually, the effect of material properties, boundary supports and temperature on the critical buckling axial load, pure lateral pressure and hydrostatic pressure of the laminated cylindrical shells are studied. Investigations indicate that volume fraction and pre-strain of SMA fibers have significant effect on the stability of the laminated cylindrical shells.