Double Plate System Research Articles

Molecular insight into the decomposition mechanism and stability of CO2 hydrate in the symmetric non-flat double-plate porous media system

Unveiling the decomposition mechanism and stability of hydrate in porous media sediments is the fundamental issue related to hydrate-based CO2 capture and sequestration. In this work, Molecular Dynamics (MD) simulations were performed to study the decomposition mechanism and stability of CO2 hydrate in the porous media of symmetric non-flat double-plate system and explore its mass transfer process. The model of CO2 hydrate in porous media possessing symmetric non-flat double-plate structure was constructed using square quartz (SiO2) as the single crystal material of porous media, illustrating the decomposition mechanism and stability law of CO2 hydrate in such media system. Simulation results indicate that there exists no pretty noteworthy discrepancy between CO2 hydrate in the symmetric non-flat double-plate porous media system and pure CO2 hydrate at the aspect of the decomposition process and sequence. The decomposition process can be divided into two stages: initial cage destruction and CO2 bubble evolution. The decomposition order proceeds in an outside to inside manner generally, with CO2 hydrate decomposition in the middle layer and diagonal region taking priority. Furthermore, the distance between media layers exerts a prominent influence on CO2 hydrate decomposition, which larger distance motivates the decomposition of CO2 hydrate easier. The results also indicated that, compared with pure water system, the stability of CO2 hydrate is greater in the symmetric non-flat double-plate porous media system, with the extreme values of DC reaching 0.64 times only than pure water system. Additionally, CO2 hydrate displayed a stronger stability in the confined space. These findings are beneficial for understanding the decomposition mechanism and stability of CO2 hydrate and provide an interesting insight into geological CO2 sequestration in sediments.

Free vibration analysis of functionally graded carbon nanotubes reinforced double plates

The specific objective of this study is to analyze the dynamics of functionally graded carbon nanotubes (FGCNT) reinforced double plates. Connected via an elastic layer, the plates have simply supported boundary conditions. In the current study, three carbon nanotubes functionally graded patterns, varying in the thickness direction are considered, including uniformly distributed, functionally graded O-pattern, and functionally graded X-pattern. Following the development of the coupled equations of motion using the Hamilton principle while considering the influences of the elastic layer, the equations are subsequently solved utilizing a two-spatial-variable modal decomposition method. For verification purposes, the equations developed are compared to simplified configurations provided in the existing studies. The solution methodology is verified through comparing against numerical results of simplified configurations of plates obtained from the development of the finite element method and existing studies. Both verifications have shown very good agreement. Influences of plates’ dimensions, carbon nanotubes reinforcement, and the stiffness of elastic layer are analyzed and provided in this study. The transverse-motion natural frequencies of the double plates are also identified, and they follow a decreasing trend as the aspect ratio increases for all the cases. The fundamental lateral-motion and axial-motion natural frequency also follows a similar trend as the aspect ratio increases. The reinforcement effect of carbon nanotubes on the transverse-motion natural frequencies is less obvious for thinner plates. An increase in the elastic layer stiffness increases the second series transverse-motion natural frequencies of the double-plate system. Among the considered functionally graded patterns, the functionally graded X-pattern reinforcement provides the largest increase in the transverse-motion natural frequencies.

Analytical solutions for double-plate systems with pasternak-type foundation in between

This paper deals with analytical solutions of double-plate system under static loads, where the connected system is composed by two parallel rectangular plates with an elastic layer in between. The plates are assumed to be represented by Kirchhoff plate model and the elastic layer is assumed to be a Pasternak elastic foundation. Analytical solutions of double-plate system based on Navier's method and Levy's approach are derived for specific conditions. Furthermore, a change of variables is used to decouple ordinary differential equations resulting from the Levy method as one of the steps to derive its corresponding homogeneous solutions. Examples for different loads and boundary conditions are presented.

Clinical study of double plate system in the treatment of complex proximal humeral fractures in the elderly

To explore the clinical outcomes of anteromedial combined with lateral locking plate for complex proximal humeral fractures in the eldery. From June 2018 to October 2020, 30 patients who underwent surgical treatment for Neer grade 3 to 4 proximal humeral fractures, including 8 males and 22 females, aged from 51 to 78 years old with an average of (61.5±7.5) years old. Of them, 15 patients had fractures fixed with anteromedial combined with lateral locking plate(ALLP group), whereas 15 received internal fixation with proximal humerus locking plate only(PHLP group). The clinical data, simple shoulder test (SST), humeral head height loss, varus angle and shoulder range of motion were compared between the two groups. All fractures were healed. The follow-up time ranged from 12 to 24 months, with an average of(14.3±2.9) months. The operation time of ALLP group was longer than that of PHLP group (P<0.05). There was no significant difference in intraoperative blood loss between the two groups (P>0.05). There was no significant difference in SST score between the two groups at 1, 3 and 12 months after operation (P>0.05). In terms of radiographic measurement, there was no significant difference in humeral head height loss and varus angle between the two groups at 1 and 3 months after operation (P>0.05). At 12 months after operation, the height loss and varus angle of humeral head in ALLP group were lower than those in PHLP group (P<0.05). In shoulder range of motion, the range of forward elevation in ALLP group was larger than that in PHLP group 1 year after operation(P<0.05). There was no significant difference in external rotation between the two groups. Anteromedial combined with lateral locking plate in the treatment of complex proximal humeral fractures in the elderly can increase the stability of the medial column and obtain a good fracture prognosis. But there are also disadvantages such as longer operation time, so it should be individualized according to the fracture type of the patient.

Static boundary element solution of double plates

This paper presents static analysis of a double-plate system using the boundary element method. The system is composed of two parallel plates with an elastic layer in between. The plates are assumed to be represented by the Kirchhoff plate model and the elastic layer is treated as a Winkler elastic foundation. The mathematical steps required to establish a boundary element technique are adequately addressed: integral equations, fundamental solution; domain integral transformation into boundary integral, and formation of an algebraic system of the double-plate problem. Numerical examples of double plate problems with different mechanical properties, boundary conditions, and load types are presented.

Free Vibration Analysis of Laminated Composite Double-Plate Structure System with Elastic Constraints Based on Improved Fourier Series Method

An analytical model of laminated composite double-plate system (LCDPS) is established, which efficiently analyzes the common 3D plate structure in engineering applications. The proposed model combines the first-order shear deformation theory (FSDT) and the classical delamination theory, and then the LCDPS’s vibration characteristics are investigated. In the process of analysis, the improved Fourier series method (IFSM) is used to describe the displacement admissible function of the LCDPS, which can remove the potential discontinuities at the boundaries. Five sets of artificial springs are introduced to simulate the elastic boundary constraints, and the restraints of the Winkler elastic layer can be adjustable. The improved Fourier series is substituted into the governing equations and boundary conditions; then, applying the Rayleigh–Ritz method, we take all the series expansion coefficients as the generalized coordinates. After that, a set of standard linear algebraic equations was obtained. On this basis, the natural frequency and mode shapes of the LCDPS can be obtained by solving the standard eigenvalue problem. By the discussion of numerical examples and the comparison with those of the reports in the literature, the convergence and the reliability of the present approach are validated. Finally, the parametric investigations of the free vibration with complex boundary conditions are carried out, including the influence of boundary conditions, lamination scheme, plate geometric parameters, and elastic coefficient between two plates.

Free vibration analysis of elastically connected composite laminated double-plate system with arbitrary boundary conditions by using meshfree method

In this paper, the meshfree method is adopted for the first time to study the free vibration of a composite laminated double-plate system (CLDPS). The first order shear deformation theory is used to analyze the free vibration of the CLDPS, and the artificial elastic spring technique is utilized to generalize its boundary conditions. All of the displacement functions including the boundary conditions are approximated by a meshfree shape function. The reliability and accuracy of the proposed technique are verified through the comparison with the results in the previous literature and by the finite element method. The effects of various boundary conditions, material properties, and geometries of the CLDPS on its natural frequencies are considered in detail.

The tolerance modelling of vibrations of periodic sandwich structures – Comparison of simple modelling approaches

In literature one can find many different modelling approaches towards sandwich structures, such as: double-plate system with an elastic core, multi-layered plate, models based on advanced deformation hypothesis, etc. Those models are significantly varying from each other with a set of assumptions made at the beginning of the modelling process. In order to determine the set of assumptions of the simple and sufficiently precise model of the sandwich plate, which would be convenient for engineers, the assumptions made in four basic models of sandwich plates are presented and discussed. Consequently, the initial systems of governing equations for vibration analysis of sandwich structures made of isotropic materials are derived. Additionally, those equations are transformed with the use of the tolerance averaging technique, so as the structures with a periodic microstructure can be also analysed. Eventually, the application of the derived models in the free vibration analysis is presented and used to assess the correctness of the modelling assumptions of every each model.

A multi-layer moving plate method for dynamic analysis of viscoelastically connected double-plate systems subjected to moving loads

This article aims to firstly introduce a computational approach, named multi-layer moving plate method (MMPM), to dynamic analysis of viscoelastically connected infinitely long double-plate systems subjected to moving loads. The Reissner-Mindlin plate theory is utilized to describe the displacement field through the thickness of each plate, whilst quadratic serendipity shape functions are employed to represent unknown fields in finite element analyses (FEAs). The governing equations of motion of connected double-plate system are established in a moving coordinate system attached to the moving load. As a consequence, the paradigm can absolutely eradicate the update process of force vector since the applied load is taken into account as “stationary” in its coordinate system. First, several numerical examples for static, free vibration and dynamic analyses are exhibited to verify the accuracy of the proposed MMPM. Then, the influences of various parameters such as load’s velocity, damping coefficient, stiffness coefficient, and plate thickness on the dynamic responses of double-plate system are examined in great detail.

Residual graft tension after graft fixation in anterior cruciate ligament reconstruction: Manual vs tensioning boot techniques

BackgroundGraft fixation at quantitative tension using a manual tensioner was advocated in ACL reconstruction, while the measured tension that is based on the surgeon's hand with the tensioner decreases after graft fixation. Therefore, our purpose is to elucidate how effectively the pre-determined graft tension maintained after final fixation of the graft to the tibia using a tensioning boot system fixed to the calf with a bandage, while monitoring the graft tension based on tibia. MethodsEight cadaveric legs (mean age: 83; 3 males and 5 females) underwent an anatomic double-bundle anterior cruciate ligament (ACL) reconstruction with hamstring tendon grafts. Two tension-adjustable force gauges were installed on the lateral femoral cortex beside the femoral tunnel. Then #5 strong suture wires through the loop end of grafts were tied to the force gauges using Endo-Buttons. After manual maximum load was repeatedly applied to each graft for 3 min, the grafts were fixed to the tibia with 10 N or 20 N at 20 degree of flexion with the following tensioning techniques using double spike plate system: (1) Manually tensioning technique (MT); (2) Tensioning boot technique with flexion-extension motion (TB-FE); and (3) Tensioning boot technique with repetitive pull (TB-RP). The residual tension at 20 was measured 3 min after grafts fixation, and also after 10 and 50 times of repeated flexion-extension motion. One-way repeated measures ANOVA was used for statistical analysis among the three techniques. ResultsThere were significant differences among three techniques fixing grafts with 10/20 N of initial tension in the residual tension 3 min after graft fixation and after 10 and 50 times of repeated flexion-extension motion. Among them, the residual tension in TB-RP was the greatest in most conditions. ConclusionTB-RP is the most secure procedure to maintain the graft tension closer to the intended initial tension in ACL reconstruction.

A study of functional outcome after osteosynthesis of intercondylar fracture of distal humerus in adults with pre-contoured locking compression plate system

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; Intra-articular fracture of distal humerus is considerable cause of morbidity in adults. The new pre-contoured LCP system provides better angular stability in fixation of inter-condylar distal humerus fracture.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; A prospective study of 25 patients with distal humerus fracture treated with pre-contoured double plate system is conducted in Department of Orthopaedics, RIMS, Ranchi between April 2017 to March 2018. These patients were followed up 3 weekly in first 3 months, then 6 weekly in next 6 months, then at every 3 month interval. Clinical and functional outcome was evaluated on the basis of Mayo elbow performance score (MEPS).&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; 24 fixed elbows were reviewed at a follow-up period of 1 year. Results obtained were graded on the basis of MEPS, 21 patients (87.5%) were graded excellent to good, fair in 2 patients (8.3%) and poor in 1 case (4.1%). Average time interval between surgery and admission was 9 days (average 4-14 days). All the fractures as well as the olecranon osteotomies united by 10-16 weeks (12.56 weeks). Superficial wound infection and transient ulnar nerve palsy was reported in 3 (12.5%) and 1 (4.16%) respectively and was managed conservatively. 1 patients did not reported in follow up.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; We conclude that osteosynthesis with pre contoured dual plating of closed intracondylar distal humerus fractures provide good fixation and early rehabilitation, leading to high rate of bone union and minimal soft tissue damage.&lt;/p&gt;

Some remarks on modelling of vibrations of periodic sandwich structures with inert core

In literature one can find many different modelling approaches towards sandwich structures, such as: double-plate system with an elastic core, multi-layered plate, models based on advanced deformation hypothesis, etc. Those models are significantly varying from each other with a set of assumptions made at the beginning of the modelling process. In order to determine the set of assumptions of the simple and sufficiently precise model of the sandwich plate, which would be convenient for engineers, the assumptions made in four basic models of sandwich plates are presented and discussed. Consequently, the initial systems of governing equations for vibration analysis of sandwich structures made of isotropic materials are derived. Additionally, those equations are transformed with the use of the tolerance averaging technique, so as the structures with a periodic microstructure can be also analysed. Eventually, the application of the derived models in the free vibration analysis is presented and used to assess the correctness of the modelling assumptions of every each model.

Dynamic characteristics of immersed plate-type fuel assemblies under seismic excitation

The present paper deals with the investigation of plate type fuel assemblies immersed in still water under simulated seismic load. In a typical high flux reactor, plate type fuel assemblies are closely arranged to achieve the high neutron flux. The coolant filled gaps between the fuel assemblies play a significant role in determining and altering its dynamic characteristics. To account the added mass and damping effects posed by the fluid film present in these gaps, a number of experimental and numerical case studies are conducted for a specific range of fluid film thickness for single and double plate systems (SPS and DPS) and square channels. A coupling beat phenomenon has been observed in DPS for a certain range of fluid film thickness. To investigate the beating phenomenon further, wavelet analysis is performed to identify the frequencies in the vibration of submerged plates. It is observed that added mass coefficient (cm) follows a linear relation while the damping coefficient (cv) follows a cubic relation with fluid film thickness. It is also found that maximum displacement of the fuel assembly is significantly small than the fluid film gap, as per the present correlations under the seismic load.

Antiplane–inplane shear mode delamination between two second-order shear deformable composite plates

The second-order laminated plate theory is utilized in this work to analyze orthotropic composite plates with asymmetric delamination. First, a displacement field satisfying the system of exact kinematic conditions is presented by developing a double-plate system in the uncracked plate portion. The basic equations of linear elasticity and Hamilton’s principle are utilized to derive the system of equilibrium and governing equations. As an example, a delaminated simply supported plate is analyzed using Lévy plate formulation and the state-space model by varying the position of the delamination along the plate thickness. The displacements, strains, stresses and the J-integral are calculated by the plate theory solution and compared with those by linear finite-element calculations. The comparison of the numerical and analytical results shows that the second-order plate theory captures very well the mechanical fields. However, if the delamination is separated by only a relatively thin layer from the plate boundary surface, then the second-order plate theory approximates badly the stress resultants and so the mode-II and mode-III J-integrals and thus leads to erroneous results.

Lengthening over nails using the double plate system ONAS-DPS.

Stable insertion of large Schanz screws behind an intramedullary (IM) nail when lengthening over nails (LON) may be difficult due to the limited bone stock. Additionally, the highly probable contact between the screws and IM nail (which is difficult to avoid) increases the likelihood of infection spreading from the skin via Schanz screws directly to the IM nail. A new device for LON has been developed. Instead of inserting Schanz screws from the external fixator beside the IM nail (as in standard LON), a system of two overlaying plates was constructed. Schanz screws can be fixed to the plates without entering the bone. The plates are fixed to the bone using four angle stability screws. The holes in the plates offer stabile fixation for a chosen angle under which the screw is positioned through the cortical bone. Using the new system there is no need to place Schanz screws behind the IM nail. Instead, Schanz screws pass to the plate and not through the bone. The new system for elongation over IM nail is called “Over Nail Angle Stability-Double Plate System” (ONAS-DPS) [Antolič V (2013) Modular side device with an intramedullary nail for guiding a bone during its lengthening. World Intellectual Property Organization. International Publication number: WO 2013/176632 A1].

Functional results after osteosynthesis of distal humeral fractures with pre-contoured LCP system.

Evaluate the functional results and determine the complications after treating distal humerus fractures with an anatomically pre-contoured double plate system. Twenty-five patients with distal humeral fractures were treated with a pre-contoured double plate system. There were 18 males (72%), 7 females (28%), with an average age of 39.68 years (22-70years). As per the AO classification, there were 4 type A fractures (16%) and 21 type C fractures (84%). In addition to clinical examination, functional results were evaluated using the Mayo elbow performance score (MEPS). Using the Mayo elbow performance score, the results obtained were graded as excellent or good results in 22 patients (88%), fair in 2 (8%) and poor in 1 (4%) of cases. Average time interval between admission and surgery was 3.8 days (average 1-9 days). All the fractures as well as the olecranon osteotomies united by 10-16 weeks (12.56 weeks). No patient had deep infection, implant failure, non-union of fracture site or olecranon osteotomy site. Superficial wound infection, which occurred in 4 (16%) patients, resolved with oral antibiotics. Transient ulnar nerve palsy developed in 1(4%) case. However, the patient recovered with conservative treatment. 1. An anatomically pre-shaped distal humerus locking plate system is useful in providing stable fixation of distal humerus fractures, thereby facilitating early postoperative rehabilitation. 2. In contrast to conventional plating, we did not observe any case of secondary fracture displacement, non-union or implant failure even in elderly patients with potentially reduced bone mass. 3. The multiple angular stable point fixation seems to be effective in the application of this system.

Clinical and radiological results of patients treated with orthogonal double plating for periprosthetic femoral fractures.

The aim of this study was to determine the outcome of surgically-treated periprosthetic femoral fractures with an orthogonal double plate system. We performed a retrospective study of ten patients (mean age 79.5 years) surgically treated for periprosthetic femoral fractures using orthogonal double plating (lateral and additional anterior plate position) from 2010 to 2013. The patients' demographic characteristics, complications and initial follow-up data were retrieved from our institutional database. After a minimum of six months post-surgery, we performed a radiological and clinical follow-up. The surgical indications for orthogonal plating were heterogenic; five patients were treated for periprosthetic fractures around their total hip prosthesis. One was treated for a fracture around a total knee prosthesis and one for an interprosthetic fracture. Additionally, three patients were treated for postoperative implant failure after the stabilisation of periprosthetic fractures around a total hip prosthesis (one) or total knee prosthesis (two). Osteosynthesis was performed using locking compression plates exclusively (length between eight and 20 holes). After a mean follow-up of 22.6 months (range, six to 42 months), two patients died, but their deaths were due to old age morbidity and were unrelated to the surgery. Surgical revision for implant failure was necessary for only one female patient due to a breakage of the lateral plate. In addition, no other failures, such as infection or non-union, were observed. At the time of follow-up, seven out of ten patients were mobile and subjectively satisfied in regards to their outcome. Based on a small number of cases, we were able to show for the first time that the use of orthogonal double plating is not associated with an increased rate of complications in patients with periprosthetic femoral fractures and stable components. Moreover, orthogonal double plating can be used successfully as a salvage procedure. At the time of follow up, seven out of ten patients were mobile. More cases must be investigated to validate our findings.

Bending solution of third-order orthotropic Reddy plates with asymmetric interfacial crack

In this paper Reddy’s third-order shear deformable plate theory is applied to asymmetrically delaminated orthotropic composite plates under antiplane–inplane shear fracture mode. A double-plate system is utilized to capture the mechanical behavior of the uncracked plate portion. An assumed displacement field is used and modified in order to satisfy the traction-free conditions at the top and bottom plate boundaries. Moreover, the system of exact kinematic conditions was also implemented into the novel plate model. An important improvement of this work compared to previous papers is the continuity condition of the shear strains at the interface of the double-plate system. Applying these conditions it is shown that the nineteen parameters of the third-order displacement field can be reduced to nine. Using the simplified displacement field the governing equations are derived, as well. The solution of a simply-supported delaminated plate is presented using the state-space model and the displacement, strain and stress fields are determined, respectively. The energy release rate and mode mixity distributions are calculated using the 3D J-integral. The analytical results are compared to those by finite element computations and it is concluded that the present model is the most accurate one among the previous plate theory-based approaches.

The system of exact kinematic conditions and application to delaminated first-order shear deformable composite plates

In this work the analysis of unsymmetrically delaminated composite plates with straight crack front is presented. It is shown that in the undelaminated region of laminated plates the problem can be captured by applying a double-plate system. The displacement continuity between the top and bottom plates requires five conditions, three of them are known in the literature, however further two are necessary to define the reference plane of the undelaminated region. This so-called system of exact kinematic conditions can be applied to any plate theory to satisfy the requirements against the displacement field. The first-order shear deformable plate theory is applied to demonstrate the applicability of the system of exact kinematic conditions. The key step of the formulation is that the in-plane displacement and the rotation parameters are not independent of each other, therefore the size of the problem can be significantly reduced. Laminated simply supported plates are analyzed by varying the position of the delamination in the thickness direction. The energy release rates and the mode mixity are calculated by using the J-integral. It is shown based on the comparison of the analytical results to those by finite element solution that if the delamination is close to the midplane of the plate, then good agreement can be obtained. In contrast, if the delamination is close to the top or bottom plate surfaces, then the first-order plate theory is not appropriate to estimate the fracture mechanics parameters of the plates.

Résultats prometteurs après traitement des fractures simples et complexes de l’humérus distal de type C par ostéosynthèse au moyen d’une double plaque angulaire stable

Summary Introduction The aim of this study was to evaluate the functional results and complications following open reduction and internal fixation of distal humerus type C fractures (AO classification) using an anatomically precontoured, angular-stable double-plate system. Patients and methods The study is a retrospective analysis of 45 patients with 46 type C fractures. There was 1 C1, 8 C2 and 31 C3 fractures. Twelve fractures were open (Gustilo classification). Follow-up was performed on 38 patients with 39 fractures (84%) after 14 months (range, 12–22). The mean age was 50 years (range, 14–87). Functional results were evaluated using the Mayo Elbow Performance Score (MEPS); the Disabilities of the arm, shoulder and hand score (DASH); and range of motion (ROM) measurements. Complications were classified as minor or major, and the postoperative and follow-up X-rays were analyzed. Results Thirty-four fractures were considered stable to allow early physical therapy. With a mean MEPS of 85 points, 36 results (36/39 [92%]) were rated as excellent or good. The mean DASH was 22.5 points, and the ROM for extension flexion was 105° (range, 50–145). Sixteen major complications (eventually coexistent: 6× implant failure, 3× non-union, 6× stiffness, 2× necrosis capitulum, 4× failure olecranon osteotomy refixation) and two minor complications were recorded in 17 patients. These adverse events led to 14 revision surgeries (14/39 [36%]). Except for extension deficit, no statistically significant differences were found between the articular simple and articular complex fractures and when comparing the results between patients with and without a major complication. Conclusion The anatomically precontoured and angular-stable double-plate system provides sufficient immediate postoperative stability to allow early physiotherapy, even in C3-type fractures. Excellent or good results could be achieved in the vast majority of patients, independent on having suffered a complication or not. Complication rates were remarkably high, emphasizing the difficulties associated with this rare type of fracture. Level of evidence: Level IV Retrospective study.