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In this article, the numerical and experimental free vibration analyses of PLA-based composite plates with different filling geometries were carried out. Firstly, the natural frequencies and modal shapes were obtained from finite element (FE) methods to characterize the vibration behavior of the plates. The obtained results were compared with experimental testing of the three-dimensional (3D) produced plates. In the comparison, it was seen that the finite element analysis and the experimental results were quite close to each other. It was also observed that the highest frequencies are measured by a triangle, then the grid and honeycomb. Moreover, higher frequencies and lower weights are possible with the triangle pattern fill. On the other hand, it is noted that the types of filling structures do not affect the modal shapes of the 3D plates. Thus, the results of this paper are of utmost importance for getting light structure and high frequencies. [ABSTRACT FROM AUTHOR]

This study investigates the electromechanical performance of piezoelectric sandwich plates both numerically and experimentally. The effect of different inner design parameters, namely the length-to-thickness, core-to-face thickness, boundary conditions and aspect ratio on both the eigenfrequency and electric potential attributes is assessed. Moreover, vibration amplitude-dependent effects are investigated. Polymer-based, sandwich plates are additively manufactured (AM) and commercially available PZT layers are surface-bonded and experimentally probed. AM smart plates are found to yield comparable eigenfrequency properties with the ones reported for fiber-reinforced smart sandwich composites. Low length-to-thickness, low core-to-face, and rectangular rather than square designs favor the electric potential performance. [ABSTRACT FROM AUTHOR]

This paper is dedicated to the homogenization and dimension reduction for a nonlinear elasticity problem of a textile structure. The structure is represented as a squared piece of cloth and modeled as a woven canvas made of long and thin fibers, crossing each other in a periodic pattern. The squared domain is partially clamped on the left and bottom. The fibers are assumed to be glued, a condition that allows to extend the woven structure to a non-perforate plate. The nonlinear elasticity problem is stated via minimization over the energy functional. The homogenization is made via the periodic unfolding method, with an additional dimension reduction. Since the existence of a minimum of the limit energy functional is not ensured, sufficient conditions for the existence are given by assuming that the material is homogeneous and isotropic. [ABSTRACT FROM AUTHOR]

The results are presented for impact of defects formed during one-sided friction stir welding plates made of alloy 1901 in the root part on the mechanical properties of resulting butt joints. The defects are represented by the lack of fusion and accumulations of oxide films in the root part of the joint. The defect length is 0.1–0.3 mm and the defects are detected using computer X-ray tomography and analyzing the microstructure of the joints using an optical microscope. The defects present in the root part of the plate joints made of alloy 1901T result in decrease in the welding factor from 0.85 to 0.74. The area of the joint break during a static tensile test shifts from the heat-affected zone to the stir zone. The break of the samples exposed to static tension is initiated by a lack of fusion (the areas occupied by oxide films) in the root part of the joint with a characteristic brittle fracture propagating into the stir zone. The fracture becomes ductile with islands of oxide film entering the weld during the welding process. The presence of the lack of fusion and oxide films in the root part of the joint results in a 2-fold decrease in the joint bending angle. A necessary condition for eliminating the lack of fusion in the root part of the butt joint in plates made of alloy 1901T deals with making the length of the rod (pin) of the working tool equal to the thickness of the workpieces welded, taking into account the degree of immersion of the tool shoulder in the weld metal. [ABSTRACT FROM AUTHOR]

AbstractThis article proposes a rigorous mathematical justification of the derivation of the governing equations of any beam and plate theory by the three three-dimensional (3D) elasticity equations. This is done by the application of the integration by part theorem via weight residual-like methods. The Fis polynomials (subscripts i and s denote the i-direction and the generic s-term of the displacement expansion uis, respectively) related to a given beam/plate theory are used as weight functions for each of the displacement unknown. To show how the method works a number of simple problems are discussed. These are related to the equilibrium equations and boundary conditions of bending beams according to shear deformation theory. Three methods for obtaining these equations are compared in some detail. The first two are the well-known methods used in mechanics of deformable bodies: (1) use of the Principle of Virtual Displacements; (2) use of the six cardinal ‘Newton’ equations of statics. The third method coincides with the one proposed and rigorously justified in this paper which is (3) the direct integration of the equations of 3D elasticity. Beam theories based on Lagrange polynomials are used as well. The latter makes it possible to immediately develop theories for layered beams and obtain so-called ‘layer-wise’ models, which are only applied here to the case of sandwich structures. Three appendixes discuss: A – The problem in which the derivative of one of the unknowns appears among the unknowns, as is the case with the Euler–Bernoulli theory; B – The extension to dynamics; C-Simple derivation of constitutive equations and related closed-form solution via Navier method. [ABSTRACT FROM AUTHOR]

Case: A 51-year-old woman, who had previously undergone C5-C7 anterior cervical discectomy and fusion, presented with symptomatic hardware failure and subsequently underwent instrumentation removal. Her postoperative course was complicated by an esophageal perforation. Despite initial repair using a rotational flap, the leak persisted, prompting esophageal reconstruction with a radial forearm free flap (RFFF). Conclusion: Persistent esophageal perforation is exceedingly rare and difficult to treat. This report discusses the surgical technique for RFFF, an excellent option for revising failed sternocleidomastoid rotational flaps. The decision between rotational repair and free flap reconstruction depends on factors such as defect size, vascularization, wound condition, and donor site morbidity. [ABSTRACT FROM AUTHOR]

The goal of this article was to review studies on distal humerus fracture plates (DHFPs) to understand the biomechanical influence of systematically changing the plate or screw variables. The problem is that DHFPs are commonly used surgically, although complications can still occur, and it is unclear if implant configurations are always optimized using biomechanical criteria. A systematic search of the PubMed database was conducted to identify English‐language biomechanical optimization studies of DHFPs that parametrically altered plate and/or screw variables to analyze their influence on engineering performance. Intraarticular and extraarticular fracture (EAF) data were separated and organized under commonly used biomechanical outcome metrics. The results identified 52 eligible DHFP studies, which evaluated various plate and screw variables. The most common plate variables evaluated were geometry, hole type, number, and position. Fewer studies assessed screw variables, with number and angle being the most common. However, no studies examined nonmetallic materials for plates or screws, which may be of interest in future research. Also, articles used various combinations of biomechanical outcome metrics, such as interfragmentary fracture motion, bone, plate, or screw stress, number of loading cycles to failure, and overall stiffness (Os) or failure strength (Fs). However, no study evaluated the bone stress under the plate to examine bone "stress shielding," which may impact bone health clinically. Surgeons treating intraarticular and extraarticular distal humerus fractures should seriously consider two precontoured, long, thick, locked, and parallel plates that are secured by long, thick, and plate‐to‐plate screws that are located at staggered levels along the proximal parts of the plates, as well as an extra transfracture plate screw. Also, research engineers could improve new studies by perusing recommendations in future work (e.g., studying alternative nonmetallic materials or "stress shielding"), clinical ramifications (e.g., benefits of locked plates), and study quality (e.g., experimental validation of computational studies). [ABSTRACT FROM AUTHOR]

A method for the optimization of the distribution of two materials in a thin symmetric plate is presented. The model for the plate is the Kirchhoff–Love and the optimization method is based on the small amplitude, or low contrast, approximation for homogenization. Numerical results are presented for compliance minimization, i.e., maximizing the global stiffness of the plate, and for minimizing the integral of an even power of the deflection in a subset of the plate. The method arrives at classical designs without the need of penalization, which allows evaluating the exact performance of the proposed shapes and the comparison with some simple intuitive designs. This also gives insight in how small the contrast needs to be for the method to give designs which are better than some intuitive designs. [ABSTRACT FROM AUTHOR]

Aim Acetabular fractures are complex articular fractures with a big challenge for orthopaedic surgeons. Surgically managed displaced fractures carry favorable outcomes, especially if the articular surface is reduced accurately. This study aims to assess the clinical outcomes of surgical-ly fixed displaced acetabular fractures with central dislocation using combined anterior and medial plating.Methods We have retrospectively evaluated sixteen patients, who had surgically managed dis-placed acetabular fractures with central dislocation at our institute. All patients underwent open reduction and internal fixation using combined anterior and medial plating via the Kocher-Langenbeck, the ilioinguinal, or the Stoppa approach. The functional outcome was assessed using the Harris Hip score.Results Our study includes sixteen patients (12 males, 4 females) with a mean age of 35 years (range: 15-53 years). The mean follow-up was 7.8 years (range: 5-13 years). Functional outcomes were good to excellent in 12 (80%) patients and fair in 3 (20%) patients. At the final follow-up, the solid union had been achieved in all fractures, the mean HHS was 88.84 ± 7.61.Conclusion Early reduction and surgical fixation of dis-placed acetabular fractures with central dislocation using combined anterior and medial plates appear to have good clinical outcomes.

Introduction. Improving the calculation methods of mechanical engineering facilities is an urgent and in-demand task. This fully applies to the techniques of calculating the strength of all-welded gastight boiler structures. Normative calculation techniques are based on simplified models that give limited possibilities for optimizing these structures. The low calculation accuracy inherent in such techniques is unacceptable under real design conditions, when an engineer is faced with the task of developing competitive structures in a short time, i.e., reducing metal consumption while providing the strength of these structures with limited development time. The use of simplified models was justified in the past, under conditions of insufficient development of computer technology. Application of the most advanced techniques based on computer modeling makes it possible to increase the accuracy of calculations, provide the optimization of such structures, and improve the quality of design. The objective of this study was to develop a new special procedure for calculating the strength of all-welded gastight structures based on computer modeling, using the most advanced methods of modeling the membrane wall and factors affecting it. The accompanying task was to verify the developed procedure based on comparing the results of calculations using the developed technique and the normative method.Materials and Methods. The developed technique is based on the replacement of the membrane wall with an orthotropic plate or shell. Computer modeling was used applying the finite element method of all-welded gastight structures, and the impacts to which they were subjected during operation, as well as an effective method for assessing the technical condition of these structures.Results. A new two-stage technique for calculating the strength of increased accuracy of all-welded gastight boiler structures was developed and patented. The calculation results were compared according to the proposed procedure and the normative method. It was shown that the proposed technique made it possible to increase the accuracy of modeling and calculation. The error in calculating all-welded gastight structures of a high-power boiler was reduced by more than 30% for the recommended steps between stiffeners. For specially reinforced membrane walls with steps exceeding the permissible values, the error reduction reached 70% or higher.Discussion and Conclusion. The developed technique is used in the modeling and calculation of all-welded gastight structures. Its application makes it possible to optimize the step between the stiffeners of the structure of the support and connecting nodes of gastight membrane walls. Based on the results of the application of the two-stage calculation procedure, new designs were developed and patented. The developed technique has been used in the real design of boilers since 2014.

Currently, bending deformations of lithospheric plates are calculated based on Kirchhoff's theory of bending of thin plates, which was formulated about 170 years ago. This paper examines the possibility of refining these calculations based on the theory of bending of thick plates developed by Timoshenko and Reissner. A new unified derivation is presented of the Timoshenko equations for 2D bending of beams and the Reissner equations for bending of slabs by direct transformation of the general elasticity equations with a simple approximate replacement of power-cubic functions with effective linear ones. This allows a more detailed and clearer understanding of the differences between the equations and the sense of the simplifications made in these theories. By comparing the analytical solutions of the Timoshenko and Reissner equations with the known test analytical solutions of the exact elasticity equations, quantitative estimates of the accuracy of these theories are given. [ABSTRACT FROM AUTHOR]

The production of homogeneous Ti–10Nb–(1–3)Mo (at %) alloys in the form of semifinished products (plates) was studied through multiple remeltings and homogenization annealing. Metallographic studies of the resulting materials in cast, rolled, and annealed states were carried out. The effect of annealing and composition on the structure, phase composition, and mechanical properties of the Ti–10Nb–(1–3)Mo alloy was revealed. Homogeneity after smelting was achieved by annealing at a temperature of 950°C for 12 h. An increase in the Mo content in the Ti–10Nb–(1–3)Mo alloy led to an increase in the strength of the alloys, while the ductility decreased. The achievement of high strength characteristics in selected alloys was associated with the development of annealing parameters after plastic deformation, namely, controlling the size of recrystallized grains and separating the α and β phases. In addition to α-Ti and β-Ti, the samples contained small amounts of ω-Ti, which led to a sharp increase in the hardness of the samples. [ABSTRACT FROM AUTHOR]

We propose a new implicit–explicit scheme to address the challenge of modeling wave propagation within thin structures using the time‐domain finite element method. Compared to standard explicit schemes, our approach renders a time marching algorithm with a time step independent of the plate thickness and its associated discretization parameters (mesh step and order of approximation). Relying on the standard three dimensional elastodynamics equations, our strategy can be applied to any type of material, either isotropic or anisotropic, with or without discontinuities in the thickness direction. Upon the assumption of an extruded mesh of the plate‐like geometry, we show that the linear system to be solved at each time step is partially lumped thus efficiently treated. We provide numerical evidence of an adequate convergence behavior, similar to a reference solution obtained using the well‐known leapfrog scheme. Further numerical investigations show significant speed up factors compared to the same reference scheme, proving the efficiency of our approach for the configurations of interest. [ABSTRACT FROM AUTHOR]

In the present study, experimental and numerical investigations are carried out on Vanadium dioxide (VO2)-UHMWPE composite plates while considering the temperature across phase change. VO2 is known for semiconducting to metallic transition along with structural changes from monoclinic to tetragonal during heating above 68°C, which enhances structural stiffness. For the experimentation, VO2-UHMWPE composite samples are fabricated by employing the Hot-Press method. These samples are further utilized to perform the compression test in order to find Young's moduli at room temperature (RT) and 75°C (temperature across phase change) using a Universal Testing Machine (UTM). Based on the experimentally computed Young's moduli, the numerical investigations in terms of free vibration and bending analyses, are performed. For structural kinematics, a C0-continuous higher-order shear deformation theory (HSDT) is employed, and the governing equations are derived using the Lagrange model. The numerical results, that is, natural frequencies and center deflection, are assessed using the finite element method (FEM). The convergence and comparison studies are accomplished to ensure the performance and competence of the present numerical model within the framework of MATLAB and ABAQUS. The influence of temperature, thickness ratio, boundary conditions, etc. on the frequency and deflection of the bare UHMWPE polymer and VO2-UHMWPE plates, is discussed in detail. Based on the results, it can be concluded that the VO2 reinforcement to the UHMWPE polymer improves structural stiffness at a temperature of 75°C. Moreover, VO2-UHMWPE composite can be utilized for structural applications, wherein lightweight and high-temperature resistive material is desired. Highlights • The fabrication of the VO2-UHMWPE composite samples is accomplished through the Hot-Press method. • Young's moduli of the VO2-UHMWPE composites at RT and 75°C are assessed utilizing UTM. • The finite element method is employed to analyze the behavior of the bare UHMWPE polymer and VO2-UHMWPE plates in free vibration and bending. • The effect of influencing parameters such as temperature, thickness ratio, boundary conditions, etc., on natural frequency and deflection of the plates are explored. [ABSTRACT FROM AUTHOR]

The solution of the nonlinear (NL) vibration problem of the interaction of laminated plates made of exponentially graded orthotropic layers (EGOLs) with elastic foundations within the Kirchhoff–Love theory (KLT) is developed using the modified Lindstedt–Poincaré method for the first time. Young's modulus and the material density of the orthotropic layers of laminated plates are assumed to vary exponentially in the direction of thickness, and Poisson's ratio is assumed to be constant. The governing equations are derived as equations of motion and compatibility using the stress–strain relationship within the framework of KLT and von Karman-type nonlinear theory. NL partial differential equations are reduced to NL ordinary differential equations by the Galerkin method and solved by using the modified Lindstedt–Poincaré method to obtain unique amplitude-dependent expressions for the NL frequency. The proposed solution is validated by comparing the results for laminated plates consisting of exponentially graded orthotropic layers with the results for laminated homogeneous orthotropic plates. Finally, a series of examples are presented to illustrate numerical results on the nonlinear frequency of rectangular plates composed of homogeneous and exponentially graded layers. The effects of the exponential change in the material gradient in the layers, the arrangement and number of the layers, the elastic foundations, the plate aspect ratio and the nonlinearity of the frequency are investigated. [ABSTRACT FROM AUTHOR]

An analysis of the influence of applied loads on free vibrations of plate and shell panels made of functionally graded materials is analyzed in the present work. Formulations for the static analysis considering geometrically nonlinear behavior, as well as linear buckling and free vibrations analyses are considered. A calculation of the through-thickness stress distribution is also performed. The finite element model is based on a higher order shear deformation theory using a non-conforming flat triangular plate/shell element with three nodes, and eight degrees of freedom per node is used in the numerical implementation. The results obtained with this numerical model are presented, discussed, and compared with alternative solutions published by other authors in some benchmark applications. [ABSTRACT FROM AUTHOR]

Purpose: In comparison to traditional, constant stiffness laminates, variable stiffness composite laminates (VSCL) with curvilinear fibres represent an extra analysis effort. It is the purpose of this work to present and test a relatively simple optimisation procedure, in order to find the maximum fundamental frequency of vibration in bending and in in-plane vibrations. It is also intended to explain why certain fibre paths lead to higher frequencies. Methods: The optimisation is performed using a genetic algorithm (GA), which is described in detail. The bending and the in-plane plate models are based on the p-version Finite Element Method. Each model requires a small number of degrees of freedom, an important feature because applying the GA involves the solution of a large number of eigenvalue problems. In order to support the physical interpretation of the optimal designs, mode shapes and stress fields corresponding to some optimal solutions are illustrated. Results: Single- and multi-layer plates with different boundary conditions and fibre path types are studied. Fibre paths that lead to maximum fundamental frequencies are found and justified. The consequences that maximising the first frequency has on the higher-order modes of vibration are studied. Conclusion: The proposed optimisation and modelling methods are effective. Curvilinear fibres with the characteristics considered led to the maximum first natural frequency of vibration in a few cases, but not all. Particularly in in-plane vibrations, curvilinear fibres can provide major gains in comparison to straight fibres. The increase in the vibration frequency is accompanied by, overall, larger stresses. [ABSTRACT FROM AUTHOR]

The design of thin-walled structures is commonly based on the solutions of linear boundary-value problems, formulated within well-developed theories for elastic plates and shells. However, in modern appliances, especially in MEMS design, it is necessary to take into account non-linear mechanical effects that become decisive for flexible elements. Among the substantial non-linear effects that significantly change the deformation properties of thin plates are the effects of residual stresses caused by the incompatibility of deformations, which inevitably arise during the manufacture of ultrathin elements. The development of new methods of mathematical modeling of residual stresses and incompatible finite deformations in plates is the subject of this paper. To this end, the local unloading hypothesis is used. This makes it possible to define smooth fields of local deformations (inverse implant field) for the mathematical formalization of incompatibility. The main outcomes are field equations, natural boundary conditions and conservation laws, derived from the least action principle and variational symmetries taking account of the implant field. The derivations are carried out in the framework of elasticity theory for simple materials and, in addition, within Cosserat's theory of a two-dimensional continuum. As illustrative examples, the distributions of incompatible deformations in a circular plate are considered. [ABSTRACT FROM AUTHOR]

In the present work, attention is paid to the nonlinear vibrations and chaotic dynamic behaviors of rotating graphene platelets reinforced metal foams (GPLRMF) blades operating in a thermal environment. Considering three different distribution patterns of graphene platelets (GPL) and foams, the improved Halpin–Tsai model, mixing rules and Maxwell-Eucken model are applied to obtain the physical parameters of rotating GPLRMF plates. The motion equations of GPLRMF rotating plates are established through higher-order shear deformation theory (HSDT), in which the centrifugal force, Coriolis force and heat conduction are included. Under the cantilever and simply supported boundary conditions, the nonlinear ordinary differential equation (ODE) of the system is obtained by Galerkin method. The amplitude-frequency response, bifurcation curve, and chaotic motion of the rotating GPLRMF blades are analyzed with the aid of the methods of multi-scale and Runge–Kutta. Furthermore, comprehensive investigations into the effects of temperature, presetting angle, GPL distribution mode, foam distribution mode, volume fraction, porosity coefficient, rotational speed, damping coefficient, and excitation force on the nonlinear dynamics of rotating plates are performed through numerical analyses. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate the results of distal femoral fracture fixation of two different methods, lateral locking plate (LP) or an Intra-medullary nail (IMN), in patients managed in our institution. More specifically, to assess: (a) if there was a difference in functional outcomes between the LP and IMN groups; (b) whether the rate of complications was different between the two groups. Methods: Between January 2009 and December 2018 adult patients with distal femoral fractures managed in our unit with either LP or IMN for extra and intra-articular fractures were eligible to participate. Demographic details, fracture type, procedures performed, time to union, complications and functional scores (Oxford Knee Score) were recorded and analysed. The mean follow up was 4 years (12–120 months). Results: Out of 193 patients who met the inclusion criteria, 93 received an IMN whereas 100 patients were treated with LP. Mean age was 64.2 (18–99) and 70.1 (18–100) for the IMN and LP groups respectively. Overall, the two groups had similar demographics and there was no significant difference in the type of fractures sustained (p > 0.05). The Oxford Knee Score was highest for patients fixed with LP, mean 37.3 (6–48, SD 7.3) versus 28.4 (3–48, SD 14.4), (p = < 0.02) compared to the IMN group. In terms of complications, the rate of non-union was higher in the LP group 8.6% versus 4% in those patients treated with an IMN, p value < 0.01. Conclusion: While the rate of non-union was higher in the LP group and the functional results were superior in the plating group. [ABSTRACT FROM AUTHOR]

An interior penalty discontinuous Galerkin method is devised to approximate minimizers of a linear folding model by discontinuous isoparametric finite element functions that account for an approximation of a folding arc. The numerical analysis of the discrete model includes an a priori error estimate in case of an accurate representation of the folding curve by the isoparametric mesh. Additional estimates show that geometric consistency errors may be controlled separately if the folding arc is approximated by piecewise polynomial curves. Various numerical experiments are carried out to validate the a priori error estimate for the folding model. [ABSTRACT FROM AUTHOR]

The solution of the nonlinear (NL) vibration problem of the interaction of laminated plates made of exponentially graded orthotropic layers (EGOLs) with elastic foundations within the Kirchhoff–Love theory (KLT) is developed using the modified Lindstedt–Poincaré method for the first time. Young’s modulus and the material density of the orthotropic layers of laminated plates are assumed to vary exponentially in the direction of thickness, and Poisson’s ratio is assumed to be constant. The governing equations are derived as equations of motion and compatibility using the stress–strain relationship within the framework of KLT and von Karman-type nonlinear theory. NL partial differential equations are reduced to NL ordinary differential equations by the Galerkin method and solved by using the modified Lindstedt–Poincaré method to obtain unique amplitude-dependent expressions for the NL frequency. The proposed solution is validated by comparing the results for laminated plates consisting of exponentially graded orthotropic layers with the results for laminated homogeneous orthotropic plates. Finally, a series of examples are presented to illustrate numerical results on the nonlinear frequency of rectangular plates composed of homogeneous and exponentially graded layers. The effects of the exponential change in the material gradient in the layers, the arrangement and number of the layers, the elastic foundations, the plate aspect ratio and the nonlinearity of the frequency are investigated.

An analysis of the influence of applied loads on free vibrations of plate and shell panels made of functionally graded materials is analyzed in the present work. Formulations for the static analysis considering geometrically nonlinear behavior, as well as linear buckling and free vibrations analyses are considered. A calculation of the through-thickness stress distribution is also performed. The finite element model is based on a higher order shear deformation theory using a non-conforming flat triangular plate/shell element with three nodes, and eight degrees of freedom per node is used in the numerical implementation. The results obtained with this numerical model are presented, discussed, and compared with alternative solutions published by other authors in some benchmark applications.

The design of thin-walled structures is commonly based on the solutions of linear boundary-value problems, formulated within well-developed theories for elastic plates and shells. However, in modern appliances, especially in MEMS design, it is necessary to take into account non-linear mechanical effects that become decisive for flexible elements. Among the substantial non-linear effects that significantly change the deformation properties of thin plates are the effects of residual stresses caused by the incompatibility of deformations, which inevitably arise during the manufacture of ultrathin elements. The development of new methods of mathematical modeling of residual stresses and incompatible finite deformations in plates is the subject of this paper. To this end, the local unloading hypothesis is used. This makes it possible to define smooth fields of local deformations (inverse implant field) for the mathematical formalization of incompatibility. The main outcomes are field equations, natural boundary conditions and conservation laws, derived from the least action principle and variational symmetries taking account of the implant field. The derivations are carried out in the framework of elasticity theory for simple materials and, in addition, within Cosserat’s theory of a two-dimensional continuum. As illustrative examples, the distributions of incompatible deformations in a circular plate are considered.

This article first introduces a novel optimization-driven reduced order model (ROM) to the dynamics of plates utilizing isogeometric analysis (IGA). The proposed paradigm uses an iterated improved reduced system (IIRS) technique to condense the system's dynamic properties. This model takes account of inertia items, the consistent mass matrix is therefore preserved. Moreover, master degrees of freedom (DOFs) defined at control points of the IGA in ROM are optimized via the derivative-free adaptive hybrid evolutionary firefly algorithm (AHEFA). Accordingly, the accuracy and the correlation of high-order shape modes can be improved. The Galerkin discretization is employed to establish the IGA-based ROM for the plate's dynamic analysis with proportional damping. In which, its weak form relied upon a generalized shear deformation theory (GSDT) is derived from the Hamilton's principle. Consequently, the reduced IGA can deal with both thick and thin plates without shear correction coefficients and the shear locking phenomenon. The Newmark- β method is then employed to achieve time-history responses of the reduced dynamic equation system. Several numerical examples are tested to illustrate the reliability and efficiency of the present methodology. Obtained outcomes have shown their useful and potential applications to the structural health monitoring (SHM) field, especially when the number of sensors is limited. • A novel optimization-based ROM using IGA is proposed for the dynamics of plates. • IIRS is utilized to condense dynamic properties with consistent mass conservation. • Master DOFs defined at control points are optimized by AHEFA. • Examples of plates' transient analysis with proportional damping are investigated. [ABSTRACT FROM AUTHOR]

The response of a circular foundation embedded in a multi-layered transversely isotropic poroelastic half-space under time-harmonic vertical loading is analyzed by treating the foundation as a classical plate and assuming the foundation-soil contact surface to be smooth and either permeable or impermeable. The displacement influence functions for multi-layered saturated soils, which are required for the present solution scheme, are obtained by employing an exact stiffness matrix method based on Biot's poroelastic model and Hankel integral transforms. A variational approach based on the discretization of the contact surface and the displacement influence functions is used to formulate the dynamic soil-structure interaction problem. Selected numerical results portray the influence of excitation frequency, foundation flexibility and permeability, embedment, soil heterogeneity and depth of water on vertical vibrations of foundations. A sensitivity analysis is also presented to illustrate the impact of the key input parameters on the dynamic response. [ABSTRACT FROM AUTHOR]

Bone fracture plates are usually made from titanium alloy or stainless steel, which are much stiffer than bone. However, overly stiff plates can restrict axial interfragmentary motion at the fracture leading to delayed callus formation and healing, as well as causing bone "stress shielding" under the plate leading to bone atrophy, bone resorption, and plate loosening. Consequently, there have been many prior efforts to develop nonmetallic bone fracture plates with customized material properties using synthetic fibers (e.g., aramid, carbon, glass) in polymer resin. Even so, plant fibers (e.g., flax, roselle, sisal) offer additional advantages over synthetic fibers, such as availability, biodegradability, less toxicity during processing, lower financial cost, and recyclability. As such, there is an emerging interest in using plant fibers alone, or combined with synthetic fibers, to reinforce polymers for various applications. Thus, this is the first review article on the material properties and engineering performance of innovative bone fracture plates made from composite materials reinforced by plant fibers alone or supplemented using synthetic fibers. This article presents material-level fiber properties (e.g., elastic modulus, ultimate strength), material-level plate properties (e.g., fatigue strength, impact toughness), and bone-plate engineering performance (e.g., overall stiffness, plate stress), as well as discussing general findings, study quality, and future work. This article may help engineers and surgeons to design, fabricate, analyze, and utilize novel bone fracture plates.

We explored the most suitable osteosynthesis type for mandibular reconstruction using fibula free flap (FFF) given the lack of robust data available. For this, an anonymous survey was e-mailed to 853 head-and-neck surgeons (France) asking about their practices and criteria guiding their osteosynthesis material and method choices. Questions assessed: (1) the most frequently used osteosynthesis type, (2) the explanatory variables related to surgeon career status/surgical specialty, and (3) justifications for osteosynthesis type (scientific, technical, "misuse"). Multivariate logistic regression was performed to test for associations of explanatory variables with plate type or misuse. Overall, 118 (13.8%) surgeons responded, among which flexible non-locking osteosynthesis was preferred (59%). Career status and surgical specialty were significantly associated with material choice. University professors/senior lecturers (OR 5.96 vs academic clinical associates; p = 0.02), but not ear-nose-throat/reconstructive plastic surgeons (OR 0.22 vs maxillofacial surgeons; p = 0.04), were more likely to opt for rigid locking osteosynthesis. Private practitioners preferred flexible non-locking osteosynthesis (OR = 5.03; p = 0.04). Only 18% of surgeons scientifically justified their choices. We considered misuse among 65% of surgeons and this was significantly associated with irregular practice of FFF surgery (OR 2.28 vs > 10 surgeries/year; p = 0.04). Overall, >50% of surgeons mainly rely on habits without scientific arguments assisting in decision-making., Competing Interests: Declaration of competing interest None of the authors have any conflicts to declare., (Copyright © 2024 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

A formulation of the asymptotically exact first-order shear deformation theory for linear-elastic homogeneous plates in the rescaled coordinates and rotation angles is considered. This allows the development of its asymptotically accurate and shear-locking-free finite element implementation. As applications, numerical simulations are performed for circular and rectangular plates, showing complete agreement between the analytical solution and the numerical solutions based on two-dimensional theory and three-dimensional elasticity theory. • A formulation of the asymptotically exact first-order shear deformation theory for plates in the rescaled coordinates and rotation angles is considered. • This rescaled formulation allows the development of the asymptotically accurate and shear-locking-free finite element implementation. • Numerical simulations are performed for circular and rectangular plates, showing complete agreement between the 2-D theory and 3-D elasticity theory. [ABSTRACT FROM AUTHOR]

This study presents normalized three-dimensional mixed-mode stress intensity factor (SIF) distributions for inclined surface cracks in finite-thickness plates under uniaxial tension. Inclination angle, aspect ratio and ratio of crack depth to plate thickness were chosen as variable parameters affecting the problem. Mixed-mode SIFs distributions are given comparatively with independent graphs for different combinations of parameters and their effects are also examined separately. The results indicate that at a constant ratio of a/c , magnitude of the normalized mode-I SIF increases with increasing ratio of a/t and decreases with increasing inclination angle, while mode-II and mode-III SIFs increase up to a specific value of inclination angle and decrease afterwards. Having compiled an extensive solution library of mixed-mode SIFs, as functions of the aforementioned parameters, regression-based equations are also generated for the crack front's free surface and deepest penetration points. It is also presented, using the principle of superposition, that the given solutions can be used for inclined surface cracks in thin-walled plate structures, such as thin-walled cylindrical pressure vessels, ship and other marine structures subjected to biaxial uniform tensile loading. • Main parameters included are; crack inclination angle, crack aspect ratio and ratio of crack depth to plate thickness. • Equations are developed for normalized mixed-mode SIFs in terms of parameters defining the problem. • Results from equations show excellent agreement with those from independent validation analyses. • Assessments of stress intensity factors for arbitrary values of parameters can accurately be made. [ABSTRACT FROM AUTHOR]

Bone fracture plates are usually made from steel or titanium, which are much stiffer than cortical bone. This may cause bone 'stress shielding' (i.e. bone resorption leading to plate loosening) and delayed fracture healing (i.e. fracture motion is less than needed to stimulate callus formation at the fracture). Thus, the authors previously designed, fabricated, and mechanically tested novel 'hybrid' composites made from inorganic and organic materials as potential bone fracture plates that are more flexible to reduce these negative effects. This is the first study to measure the cytotoxicity of these composites via the survival of rat cells. Cubes of carbon fiber/flax fiber/epoxy and glass fiber/flax fiber/epoxy had better cell survival vs. Kevlar fiber/flax fiber/epoxy (57% and 58% vs. 50%). Layers and powders made of carbon fiber/epoxy and glass fiber/epoxy had higher cell survival than Kevlar fiber/epoxy (96%-100% and 100% vs. 39%-90%). The presence of flax fibers usually decreased cell survival. Thus, carbon and glass fiber composites (with or without flax fibers), but not Kevlar fiber composites (with or without flax fibers), may potentially be used for bone fracture plates., (© 2024 IOP Publishing Ltd.)

Introduction: When it comes to the bones the most frequent lesions are the fractures, but the challenges in the orthopedic practice are not about bone repair, rather these challenges revolve around preserving the surrounding important anatomical structures, in order to have the best outcome for the patient's recovery. Case Report: We present a case of a 69-year old female patient, presented at the emergency department, conscious, with fall trauma from the same level, pain localised in the upper left limb, low range of mobility and with pathological history of high blood pressure, diabetes. Laboratory result: elevated number of leukocytes, low average level of Hb, increased number of neutrophils. The X-ray reveals the diagnosis - distal humerus fracture. The patient is admitted for the surgical treatment - distal humerus plate surgery - procedure that involves first repositioning the bone fragments into the anatomical position and held them in place with plates and securing them with screws, from the outside part of the plates. Discussions : As mentioned the most challenging part of the surgery are immediate complication - to preserve the surrounding anatomical structures, the ulnar nerve and the radial nerve, structures that could be damaged by the fracture itself or during the collecting and repositioning part of the surgery; and the long time complications - joint stiffness, pain due the medical device, pseudoarthrosis, delayed consolidation. The procedure involves a long period of recovery, 3 weeks of plaster cast, hinged orthosis for progressive extension. Conclusions: In the surgical displaced intervention, osteosynthesis is an important factor for recovery. The method can restore the bone and the patient can regain the joint mobility. Even if it is a long journey, long term outcomes are good for the patients. [ABSTRACT FROM AUTHOR]

This study aims to assess the outcomes of mandibular fractures treated through surgical stabilization using plates and screws, focusing on factors such as postoperative complications, patient satisfaction, and functional recovery. A total of 42 patients were included in the study. Surgical interventions involved the application of plates and screws at the fracture sites. Postoperative complications, including infection, hardware failure, and malocclusion, were recorded. Surgical stabilization of mandibular fractures using plates and screws demonstrates favorable outcomes in terms of stability, occlusal alignment, and patient satisfaction. The findings of this study contribute valuable insights into the efficacy of this surgical approach, highlighting its role in achieving successful outcomes for mandibular fracture management. Further prospective studies and randomized controlled trials are recommended to strengthen the evidence base and refine treatment protocols., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Rai et al.)