Stability Of Plates Research Articles

Management of segmental defects post open distal femur fracture using a titanium cage combined with the Masquelet technique A single-centre report of 23 cases

IntroductionThe segmental bone defects post open distal femur fracture presents a reconstructive challenge, which often requires extreme solutions. The present study reviewed a new treatment strategy which used a cylindrical titanium mesh cage as an adjunct to the Masquelet technique. MethodsWe retrospectively reviewed a consecutive series of 23 patients treated for segmental bone defects post open distal femur fracture using a titanium mesh cage combined with the Masquelet technique under a 2-staged protocol in our institution from 2017 to 2021. The study group consisted of 13 men and 10 women with an average age of 44.1 years. The surgical debridement was performed with antibiotic polymethylmethacrylate (PMMA) cement spacer implanted into the bone defect combined with cement-wrapped plate stabilization, or antibiotic beads with vacuum sealing drainage (VSD) to cover the wound. The second stage of the Masquelet technique for bone defect repair began at least 4–6 weeks after the first stage, once all signs of possible infection were eliminated. After the cement spacer was removed, the definitive reconstruction was completed with exchange to a cylindrical titanium mesh cage filled with cancellous autograft within the induced membrane. The bone defect with cage was stabilized with a distal femoral Less Invasive Stabilization System (LISS). The radiological and clinical records of the enrolled patients were retrospectively analyzed. ResultsThe mean follow-up was 38.6 months. The average number of operations before the second stage was 1.3. The mean interval between the two stages was 12.7 weeks. The average length of the defect measured 8.3 cm (ranging from 6.1 to 12.4 cm). All the defects filled with autograft within the cage achieved bony union, with a mean healing time of 8.4 months. At the latest follow-up, the mean knee extension measured 6.2° (ranging from 0° to 20°), and the mean flexion measured 101.8° (ranging from 60° to 120°). Complications included two instances of superficial stitch abscess, which eventually healed. ConclusionsThe use of a titanium cage implanted into an induced membrane in a 2-staged Masquelet protocol could achieve satisfactory clinical outcomes in cases of segmental defects following open distal femur fractures.

In Situ Observation of Room‐Temperature Magnesium Metal Deposition on a NASICON/IL Hybrid Solid Electrolyte

AbstractSecondary batteries using multivalent cations as ionic charge carriers have attracted increasing attention in recent years due to the high theoretical energy density provided by multi‐electron redox reactions. However, the high charge density of these cations inevitably leads to sluggish kinetics of ion migration at room temperature, which poses a challenge for the development of solid‐state batteries using multivalent ions. Here, a magnesium ion conducting hybrid solid electrolyte (HSE) is prepared, consisting of a new NASICON‐structured material, Mg0.5Sn2(PO4)3, and a small amount of magnesium ionic liquid. The HSE shows superior room‐temperature ionic conductivity of 1.11 × 10−4 S cm−1 and an activation energy of 0.36 eV. Due to the good compatibility of the HSE with the magnesium metal anode, symmetric MgǀHSEǀMg cells show stable magnesium plating and stripping behavior at room temperature. Using in situ electrochemical scanning electron microscopy measurements, the room temperature growth‐induced fracture of the HSE is observed, giving unequivocal evidence for magnesium deposition. These results may serve as a starting point for understanding the magnesium deposition mechanism on solid electrolytes in solid‐state batteries.

In Situ Generated Electron-Blocking Lih Enabling An Unprecedented Critical Current Density of Over 15Ma Cm-2 for Solid-State Hydride Electrolytes.

LiBH4 is a promising solid-state electrolyte due to its thermodynamic stability to Li. However, poor Li-ion conductivities at room temperature, low oxidative stabilities and severe dendrite growth hamper its application. Herein, weadopted a partial dehydrogenation strategy to in situ generate an electronic blocking layer dispersed of LiH, addressing the above three issues simuteneously. The electrically insulated LiH reduces the electronic conductivity by two orders of magnitude, leading to a 32.0-times higher critical electrical bias for dendrite growth on the particle surfaces than that of the counterpart. Additionally, this layer not only promotes the Li-ion conductance by stimulating coordinated rotations of BH4 - and B12 H12 2- , contributing to a Li-ion conductivity of 1.38 × 10-3 S cm-1 at 25 °C, but also greatly enhances oxidation stability by localizing the electron density on BH4 - , extending its voltage window to 6.0V. Consequently, this electrolyte exhibits an unprecedented critical current density of 15.12mA cm-2 at 25 °C, long-term Li plating and stripping stability for 2700h, and a wide temperature window for dendrite inhibition from -30 to 150 °C. Its Li-LiCoO2 cell displayed high reversibility within 3.0 to 5.0V. We believe this work provides a clear direction for solid-state hydride electrolytes. This article is protected by copyright. All rights reserved.

Treatment of Soft Tissue Defects after Minimally Invasive Plate Osteosynthesis in Fractures of the Distal Tibia: Clinical Results after Reverse Sural Artery Flap.

Introduction: Distal tibial fractures make up approximately 3% to 10% of all tibial fractures or about 1% of lower extremity fractures. MIPO is an appropriate procedure and method to achieve stable metal plate fixation and osseointegration by minimizing soft tissue damage and vascular integrity at the fracture site. MIPO to the medial tibia during distal tibial fractures induces skin irritation due to the thickness of the metal plate, which causes discomfort and pain on the medial side of the distal leg, and if severe, complications such as infection and skin defect may occur. The reverse sural flap is a well-researched approach for covering defects in the lower third of the leg, ankle, and foot. Materials and Methods: Among 151 patients with distal tibia fractures who underwent minimally invasive metal plate fixation, soft tissue was injured due to postoperative complications. We treated 13 cases with necrosis and exposed metal plates by retrograde nasogastric artery flap surgery. For these patients, we collected obligatory patient records, radiological data, and wound photographs of the treatment results and complications of reconstructive surgery. Results: In all the cases, flap survival was confirmed at the final outpatient follow-up. The exposed area of the metal plate was well coated, and there was no plate failure due to complete necrosis. Three out of four women complained of aesthetic dissatisfaction because the volume of the tunnel through which the skin mirror passed and the skin plate itself were thick. In two cases, defatting was performed to reduce the thickness of the plate while removing the metal plate. Conclusions: Metal plate exposure after distal tibial fractures have been treated with minimally invasive metal plate fusion and can be successfully treated with retrograde nasogastric artery flaps, and several surgical techniques are used during flap surgery.

Hard tissue stability outside the buccal bone arch contour after guided bone regeneration in the anterior maxilla: A retrospective cohort radiographic study.

To radiographically evaluate the stability of the bone substitute augmented outside the buccal bony arch contour in the maxillary esthetic zone. Patients who missed a single anterior tooth and received simultaneous GBR in implant surgery were included. The contralateral homonymous area of the implant site was horizontally mirrored as the individual bone arch contour. According to the relative position of the postoperative buccal grafts and bone arch contour at the implant shoulder, 62 patients were allocated into the outside-contour (OC) and inside-contour (IC) groups. Cone-beam computed tomography was performed before surgery, after implant insertion, before re-entry surgery, and at follow-up. The profilometric changes of the buccal bone plate were analyzed via the bone distance to the mirrored bony contour. At the implant shoulder, the bone distance in the OC group was higher than that in the IC group, with statistically significant differences at re-entry surgery and follow-up. However, the bone grafts outside the bone arch contour were reduced into the contour after remodeling and showed more bone resorption than the IC group. At other vertical levels below the implant shoulder, bony grafting of overcontour 1-2 mm range was favorable to regenerate stable bone plates reaching the individual contour at follow-up. The overaugmented bone outside the buccal bone arch contour tended to remodel into the original contour, which indicates that the anterior bone arch contour is worthy of careful observation for deciding buccolingual implant position and bone augmentation width.

Single‐Ion Conducting Polymer Electrolyte for Superior Sodium‐Metal Batteries

AbstractSodium‐metal batteries (SMBs) are considered a potential alternative to high‐energy lithium‐metal batteries (LMBs). However, the high reactivity of metallic sodium towards common liquid organic electrolytes renders such battery technology particularly challenging. Herein, we propose a multi‐block single‐ion conducting polymer electrolyte (SIPE) doped with ethylene carbonate as suitable electrolyte system for SMBs. This novel SIPE provides a very high ionic conductivity (2.6 mS cm−1) and an electrochemical stability window of about 4.1 V at 40 °C, enabling stable sodium stripping and plating and excellent rate capability of Na||Na3V2(PO4)3 cells up to 2 C. Remarkably, such cells provide a capacity retention of about 85 % after 1,000 cycles at 0.2 C thanks to the very high Coulombic efficiency (99.9 %), resulting from an excellent interfacial stability towards sodium metal and the Na3V2(PO4)3 cathode.

Single-Ion Conducting Polymer Electrolyte for Superior Sodium-Metal Batteries.

Sodium-metal batteries (SMBs) are considered a potential alternative to high-energy lithium-metal batteries (LMBs). However, the high reactivity of metallic sodium towards common liquid organic electrolytes renders such battery technology particularly challenging. Herein, we propose a multi-block single-ion conducting polymer electrolyte (SIPE) doped with ethylene carbonate as suitable electrolyte system for SMBs. This novel SIPE provides a very high ionic conductivity (2.6 mS cm-1) and an electrochemical stability window of about 4.1 V at 40 °C, enabling stable sodium stripping and plating and excellent rate capability of Na||Na3V2(PO4)3 cells up to 2C. Remarkably, such cells provide a capacity retention of about 85% after 1,000 cycles at 0.2C thanks to the very high Coulombic efficiency (99.9%), resulting from an excellent interfacial stability towards sodium metal and the Na3V2(PO4)3 cathode.

Clavicle fractures: practical approach in clinical routine

Fractures of the clavicle are among the most common fractures. They typically result from afall onto the lateral shoulder or the extended arm and are often related to sports and bicycle accidents. Obtaining the exact trauma mechanism, proper clinical findings and adequate X‑rays usually lead to the correct diagnosis. Non-displacement fractures can be treated conservatively with good results. Unstable and displaced fractures should be treated operatively. Open fractures or looming penetration are emergencies und should be treated immediately. In addition to fracture classification and morphology, other factors such as additional injuries and patient-related factors need to be considered in order to make an individualized therapy decision. In operative treatment, angular stable plating is the therapy of choice, and in most cases early functional aftercare is possible.

Efficacy comparison of Kirschner-wire tension band and anchor loop plate in treatment of olecranon fracture.

Objective: This study aimed to introduce a new surgical method for the fixation of olecranon fractures, and to compare the biomechanical stability and clinical efficacy of Kirschner wire tension band and anchor loop plate (ALP) in the treatment of olecranon fractures. Methods: A finite element model was established to analyze the mechanical properties of Kirschner wire tension and anchor loop plate fixation for olecranon fracture. The clinical data of 53 patients with olecranon fractures admitted to our hospital from March 2016 to October 2021 were retrospectively analyzed. Among them, 22 cases were fixed with an anchor loop plate (ALP group), and 31 patients were fixed with the Kirschner wire tension band technique. By reviewing the medical records and follow-up results, the final elbow mobility, secondary surgery, postoperative complications and elbow function recovery Mayo score and DASH score were compared between the two groups. Results: The biomechanical analysis of the finite element model showed that under the load of 120N, the maximum displacement of the Kirschner wire group was 1.09 times that of the ALP group, the maximum stress of the Kirschner wire group was 1.33 times that of the ALP group, and the maximum stress of the olecranon proximal bone of the Kirschner wire group was 2.17 times that of the ALP group. Under the load of 200N, the maximum displacement of the Kirschner wire group was 1.19 times that of the ALP group. The overall maximum stress of the Kirschner wire group was 1.59 times that of the ALP group, and the maximum stress of the proximal olecranon bone of the Kirschner wire group was 1.99 times that of the ALP group. The average follow-up time of the Kirschner wire and anchor loop plate groups was similar (p > 0.05). The average age of the two groups was identical (p > 0.05). The final elbow mobility in the anchor loop plate group was significantly greater than in the Kirschner wire group (p < 0.05). The Mayo score of the anchor loop plate group was substantially higher than that of the Kirschner wire group at 3 and 12months after operation (p < 0.05), and the DASH score was significantly lower than that of the Kirschner wire group (p < 0.05). Postoperative complications in the two groups: 1 case (4.5%) in the anchor loop plate group had difficulties with internal fixation stimulation, and no infection occurred; in the Kirschner wire group, 5 cases (16.1%) had complications of internal fixation stimulation, and 1 patient (3.2%) had an infection. Conclusion: The model of olecranon fracture fixed by anchor loop plate and Kirschner wire tension technique was tested under 120 and 200N tension, and no damage was found, indicating that the newly designed anchor loop plate was safe in mechanical structure. The biomechanical stability of the anchor plate technique is more stable, so it is not easy to have postoperative complications such as fracture block cutting and internal fixation failure. And the secondary operation rate and elbow function have better results. This technique is an effective method for the treatment of olecranon fractures.

Hybrid Liquid–Solid Composite Electrolytes for Sulfide‐Based Solid‐State Batteries: Advantages and Limitation

AbstractAll‐solid‐state batteries (SSBs) represent one of the most promising avenues for surpassing the energy density limitations of conventional lithium‐ion batteries. However, the unstable interfacial contact between the solid‐state electrolyte and the electrode poses a critical challenge for practical applications. To tackle this issue, a hybrid system incorporating both liquid electrolytes (LEs) and sulfide solid‐state electrolytes may serve as a viable alternative. In this hybrid system, the LE facilitates the in situ formation of a solid electrolyte interphase layer, thereby enhancing the physical interface contact. Consequently, the electrochemical lifetime of the hybrid all‐SSBs is significantly improved, as evidenced by the stable lithium plating behavior observed through analytical techniques such as in situ X‐ray imaging. Nonetheless, the hybrid system exhibits clear limitations, and several issues that need to be addressed for its practical implementation are identified. In conclusion, potential solutions that could be employed to overcome these challenges are proposed.

Experimental Local Stability of 3D‐printed Stub Columns Stiffened by Sinusoidal Waves

AbstractTraditional structural steel manufacturing routes typically produce prismatic members comprising of flat plates. Under compressive actions, the capacity of these sections is often dominated by plate instability of the lowest buckling mode. To validate a new plate strengthening method by assigning ‘higher‐order’ 2D sinusoidal waves to plated structures, this study involves experimental testing of 3 prismatic SHS stub columns and 6 non‐prismatic members strengthened by this method. The test samples were 3D printed in 316L stainless steel using Selective Laser Melting. Tensile coupon tests were carried out on samples printed from the same material to obtain the material properties. It was found that the yield strength increases with the plate thickness whilst ultimate strength remains approximately unchanged. The stub column test results show that assigning 2D sinusoidal waves to EAS flanges can bring different levels of strength enhancement compared to their prismatic counterparts, depending on the section slenderness and the wave amplitude. The best case evaluated within this study indicated a strength gain of 31% over the prismatic section with only a 3.2% increase in used material. It makes an important step in bringing this technology towards feasibility by verifying previous numerical results, paving the way towards unprecedented efficiency in future steel structures.

A refined quasi-3D isogeometric model for dynamic instability of graphene nanoplatelets-reinforced porous sandwich plates

This study pays attention to the dynamic instability behavior of advanced sandwich plate structures subjected to periodic in-plane compressive loads. By utilizing a powerful and efficient computational approach based on a four-variable refined quasi-3D plate theory and NURBS-based isogeometric analysis (IGA), the dynamic behavior of structures can be accurately evaluated while accounting adequately for the thickness stretching effect of normal deformation. To investigate the dynamic instability behavior, this study examines sandwich plate models that consist of two graphene nanoplatelets (GNPs)-reinforced skin layers and a porous core layer with two typical distributions of internal porosity: uniform and symmetric dispersion. Bolotin's method is applied in this study to solve the Mathieu–Hill equation and obtain the boundary of dynamic instability zones. Numerical examples are performed to examine the influence of various input parameters on the instability regions, as well as to provide new insights into the dynamic instability behavior of advanced sandwich plates under compressive loading which has not been comprehensively studied in the literature. The findings of this study suggest that the thickness stretching effect should be carefully evaluated for moderate to thick plate structures, such as sandwich plates.

(Invited) Solvation and Double Layer Structures in Nonaqueous Electrolytes for Facile Electrochemical Kinetics

Nonaqueous electrolytes are indispensable for high-voltage/high-energy electrochemical systems. They are particularly important for batteries that can work normally at very low temperatures and can be recharged at high C-rates. Under these extreme conditions, solvation and double layer structures at the electrolyte-electrode interfaces, which were considered less critical than other processes like solid-phase diffusion, appear to play an important role in enabling fast reaction kinetics. Due to the use of multiple co-solvents, salt mixtures, and various additives in novel nonaqueous electrolytes, the interfacial solvation and double layer structures are no longer as simple as the classical understanding based on aqueous electrolytes. In this presentation, we will introduce our recent efforts in realizing fast ion intercalation (both anions and cations) in graphite electrodes and ideally stable alkali metal plating in nonaqueous electrolytes in wide ranges of current densities and temperatures. By combining classical molecular dynamic (MD) simulations of the interfacial electrolyte structure near a charged electrode, density functional theory (DFT) calculations of the distorted solvation structures, operando microscopy of the electrode reactions, and postmortem chemical analysis of the solid-electrolyte interphase (SEI) layers, we confirmed the importance, necessity, and principle of formulating high-performance electrolytes based on molecular scale understandings of the complex interfacial structures.

(Invited) Stable Anode-Free All-Solid-State Lithium Battery through Tuned Metal Wetting on the Copper Current Collector

It is demonstrated that a standard copper foil current collector with appropriately modified surface chemistry will allow for stable lithium cycling in an anode-free all-solid-state lithium battery (AF-ASSB). An argyrodite solid electrolyte Li6PS5Cl (LPSCl) is employed without any modifications or secondary interlayers. The tuned lithophilic copper surface allows for stable plating and stripping, reducing the overpotentials and significantly improving the Coulombic efficiency (CE). During continuous plating experiments using half-cells (1 mA cm-2), the accumulated thickness of electrodeposited Li on Li2Te-Cu is more than 70 μm, which is the thickness of Li foil counter-electrode. Full AF-ASSB with NMC811 cathode delivers an initial CE of 83% at 0.2C, with a cycling CE above 99%. Post-mortem cryo-FIB-SEM analysis demonstrates uniform electrodeposited metal microstructure, with no signs of voids or dendrites at the collector-SE interface. The same copper current collector but unmodified leads to inhomogeneous Li plating, with “dead metal” formation and an irregular honeycomb-like solid electrolyte interphase (SEI) interspersed with pores. Density functional theory and mesoscale calculations provide complementary insight regarding nucleation-growth behavior. Unlike for conventional liquid-electrolyte metal batteries, the role of current collector/support lithiophilicity has not been explored for emerging AF-ASSBs. Figure 1

Development of a scheme for the distribution of contact areas between the plate and offset cylinders

The object of the research is the distribution of contact areas between the plate and offset cylinders. For printing impression in the offset printing process, it is necessary to ensure the transfer of printing ink from the ink unit to the printing plate, from the mold to the rubber-fabric material (deckel) of the offset cylinder and from the deckel to the printed material. At the same time, the quality of the prints is ensured by creating the necessary technological pressure between the plate, offset and printing cylinders, which also contributes to the deformation of the elastic deckel and the transfer of the ink layer in the contact zone. The transfer of illustrative and textual information from the form to the deckel of the offset cylinder occurs due to the actual touch area. Therefore, the study and calculation of the actual contact area is necessary to study the transfer of the paint layer in the contact zones. For this purpose, a review of some studies on contact problems was carried out, their advantages and disadvantages were discussed. Theoretical and experimental relations are given. It has been established that micro protrusions of the surface roughness of the printing plate significantly affect the deformation of the deckel. To study the influence of the surface roughness distribution of the printing plate on the actual deckel contact area in the contact zone, the interaction of micro protrusions of the surface roughness of the printing plate with the deckel surface, leading to additional displacements, was taken into account. A method for calculating the number of roughness protrusions is proposed to further determine the actual deckel contact area and the actual pressure in the contact zone, taking into account the surface roughness of the printing plate. Based on the parameters calculated by the proposed method with known values of the surface roughness of the printing plate in the future it is possible to determine the actual deckel contact area and the actual contact pressure the optimal values of which are necessary to ensure the required ink transfer and print quality during printing. The data obtained also contribute to the determination of the modes of the printing process when printing the entire circulation, which leads to an increase in the circulation stability of printing forms. Increasing the circulation stability of printing plates allows to save the number of consumed printing plates. In the future, according to the results obtained, it is recommended to compile reference data, which are necessary when setting up and operating the printing machine.

Angle Stable Plate Fixation vs Hemicallotasis in Medial Opening Wedge High Tibial Osteotomy: A Comparative Study.

Varus alignment associated with medial compartment degeneration is the most common presentation of knee osteoarthritis and often presents in young active adults where arthroplasty might be unsuitable. To compare the accuracy of the angle stable medial high tibia plate and self-adjusting HTO (high tibial osteotomy) fixator in achieving correction of varus deformity of the knee by medial opening wedge HTO and to evaluate functionality between the groups. Prospective randomized control study. Forty patients each underwent medial opening wedge high tibial osteotomy with acute correction and stabilization using the angle stable plate (ASP group) or with the hemicallotasis technique using the self-adjusting HTO external fixator (HCO group). Anatomical and functional outcomes were compared to the pre-operative values at the 6th and 12th month. The FTA (femoro-tibial axis), mechanical axis, and functional scores improved significantly in both groups. There was also a significant change in the patellar height and tibial slope. Except for a better KOOS (Knee Injury and Osteoarthritis Outcome Score) in the angle stable plate group at the 6-month follow-up, there were no significant differences between the groups. Both methods of performing a medially based proximal tibial osteotomy gave equivalent outcomes at the 1-year follow-up.

Nonlinear parametric excitation and dynamic stability of auxetic honeycombs core with CNTRC face sheets sandwich plate

This study aims to analyze the Nonlinear vibration and instability of a sandwich plate with an Auxetic Honeycomb core and a Carbon Nanotube Reinforced Composite (CNTRC) face layer on a viscous elastic foundation under parametric excitation. In the analytical model, the Hamilton principle and nonlinear strain-displacement relations determined by Von Karman theory and the first shear deformation plate theory (FSDT) are used. The governing equations are solved using the Galerkin method, which involves expanding the displacement field based on orthogonal functions. Once the displacement field has been expanded, a multiple-scale method is used to solve the equation of motion. The results show that the bifurcation diagrams and stability of sandwich plates depend on several parameters, including the geometric dimension of the honeycomb core, the material properties of the CNTRC face layer, and the temperature increment. The results of this study will likely be helpful in optimizing the design of sandwich plates for engineering applications, including the aerospace and automotive industries, where sandwich structures are widely utilized because of their high strength-to-weight ratios and excellent energy absorption capabilities.

The Impact of Geometry on the Mechanical Stability of Plates for Internal Bone Fixation

The Impact of Geometry on the Mechanical Stability of Plates for Internal Bone Fixation

Mechanical behaviour of reconstructed defected skull with custom PEEK implant and Titanium fixture plates under dynamic loading conditions using FEM

Skull reconstruction using cranial implants is often required for repairing skull defects caused due to trauma, diseases, or malignancy to protect intracranial structures. For relieving Intracranial Pressure (ICP) surgeons restore cranial defects either using natural bones or fabricated custom cranial implants. With the increase in Traumatic Brain Injuries (TBI) and challenges faced by TBI patients to regain normalcy, it is imperative to analyse the mechanical behaviour of skull-implant assemblies under some Head Injury Criteria (HIC). Medical grade materials including Titanium Alloys (Ti-6Al-4V) and Polyether-ether-ketone (PEEK) are used by fabricating Patient-Specific Implants (PSI) manufactured using 3D imaging, modelling and printing techniques. 3D technologies are preferred over conventional manufacturing methods, as they enable fabrication of custom shapes, sizes and properties for these PSI.For an effective attachment of PSI with a defective skull, a stable joint and plate arrangement as fixture plates is necessary at their interface. These fixtures can have variable numbers, design shapes, materials and location arrangements.This paper presents the Finite Element Method/Analysis (FEM/FEA) study of PSI attached to a defected skull for reconstruction, with linear shaped fixture configuration, when subjected to an external dynamic loading at 5 m/s, strain rate of 10s−1 to 243s−1 and ICP of 15mm Hg from three sides of the skull faces. Three different materials as Neoprene (soft), Concrete (medium rigid) and E-Glass (highly rigid) have been used, in the form of a rectangular thin cuboidal wall structure, at an angle of 45° with the skull face. Four linear shaped fixture plates which were simplest to design, were used to attach the PSI-skull assembly, to ensure that weight of the PSI-fixation assembly on the patient remains minimal, overall assembly has symmetrical fixations and efforts required by a surgeon for fitment of these plates remain minimal. Placement of these fixture plates has been optimized to encompass the complete PSI-skull interface section, due to which the stresses within all the assembly components (PSI, fixture plate and skull) reduced by nearly 2.5 times than the initial design and remained within yielding limits, thereby, averting any failure under heavy external dynamic loading.

Ensuring the Stability of Channel Linings Under Unsteady Filtration

When assessing the stability of the slopes of the banks of reservoirs and channels, the filtration regime that occurs with a rapid decrease in the water level in the upstream, which is due to the nature of the operation of structures before floods, discharges, emergency situations, is of particular interest. A change in the water levels in the upstream causes a change in the position of the depression surface and the parameters of the filtration flow (pressure gradients, filtration rates and flow rates) in the coastal massif. At the same time, unsteady filtration occurs in the coastal massif and the stability of the slopes is reduced significantly due to the action of hydrodynamic forces directed towards the slope. The most reliable anchors of channel slopes in similar conditions are those that, under normal channel operation, when there is no groundwater support, the lining should exclude filtration from the channel, ie filtration losses of irrigated water, and if there is a backwater and with a rapid decrease in the water level in the channel, it should provide free access of the ground stream into the channel channel or its diversion in the other direction. This eliminates the occurrence of significant hydrodynamic pressures, and the destruction of the channel slope fasteners. The article presents the results of studies of 4 designs of channel linings operating under conditions of unsteady filtration. In the course of the study, we considered the following variants of structural schemes of linings. Fastening with combined deformation and filtration seams; fastening with self-collapsing seams; fastening with discharge tubular drains with water discharge into the channel; fastening with filtration and discharge holes arranged during the appearance of groundwater backup in the channel area. The results of calculating the stability of the fastening plates for overturning and surfacing are presented. According to the results of the calculation, the most acceptable fastening options are determined, their advantages and disadvantages are given. The proposed fastening design meets the above requirements and thereby ensures the strength and stability of the linings during the operation of the channel.