Metal Liner Research Articles

Burst pressure estimations of a composite pressure vessel accounting for the composite shell imperfections

The paper presents the numerical evaluation of the effect of possible imperfections on the burst strength of composite pressure vessel made by filament winding over a thin metallic liner. The damages and defects distributed over the composite volume that lead to deterioration of the mechanical properties or increase their scattering are considered. The burst pressure is predicted with finite element analysis by using progressive damage approach. The obtained results show a strong influence of initial imperfection in the composite laminate on the vessel strength. The performed calculations show that the failure of the weakest layers does not lead to loss of the load-carrying capacity of the composite shell and the structure burst occurs as results of the subsequent damage evolution process. Such phenomenon happens regardless of the level of initial imperfection.

Density Effect of PTFE-Copper Powder Metallurgy Liner Material on the Perforation Performance of Shaped Charge Jets

The aftereffect damage efficiency of shaped charge jets formed with the conventional metal liner against light armor is quite low. The validity of the PTFE-copper powder metallurgy liner material prepared by the cold pressing-sintering-compound pressing forming technique is experimentally studied and numerically simulated. The models of constitutive state and dynamic mechanical behavior were adapted to the specific shaped charge liner design. Shaped charge jets formed with the powder metallurgy material liner was shown to cause a higher surface target damage after breaking the light armor down, thus exhibiting an improved aftereffect damage efficiency.

국내 원전 격납건물 금속 라이너에 대한 가동중검사 현장경험

국내 원전 격납건물 금속 라이너에 대한 가동중검사 현장경험

On the finite element modeling of COPVs

In this paper we discuss the finite element modeling of Composite Overwrapped Pressure Vessels (COPVs) which are used in the aerospace industry, when high strength/weight ratios are required, for containers filled with pressurized fluids. The COPVs that we analyze are composed by a thin metallic liner and an external reinforcement made with high strength fibers that are wrapped around the liner embedded in an epoxy resin. It is shown in the paper that for a reliable description of the vessels behavior under internal pressure it is required to use a model that incorporates the mechanical behavior of the liner, of the fibers and of the resin matrix (micromechanical model).

Aluminium Lined, Carbon Composite Overwrapped Pressure Vessel

A numerical analysis of filament-reinforced internally pressurized cylindrical vessel with over-wrapped metallic liner is presented, the study deals with simulation of aluminium liner pressure vessel overwrapping by composite T800/epoxy was selected, ABAQUS Software was use in which 20 layers of composite were analysed. The stress state of the pressure vessel under the internal pressure of 33MPa was analysed, and the bursting strength was predicted to be 92.3MPa. MATLAB software was used to simulate the winding process, the 5 axis numerical control winding machine was used for the actual winding, and the fibres were arranged in a regular and uniform way, and the sliding phenomenon was not occurred. After solidifying, the bursting strength was 85.4MPa, and the difference between the actual value and the predicted value was 6.9%. The experimental results were in good agreement with the simulation results.

Investigation of convergent Richtmyer–Meshkov instability at tin/xenon interface with pulsed magnetic driven imploding**Project supported by the National Natural Science Foundation of China (Grant Nos. 11605183 and 11502254).

The Richtmyer–Meshkov instability at the interface of solid state tin material and xenon gases under cylinder geometry is studied in this paper. The experiments were conducted at FP-1 facility in Institute of Fluid Physics, China Academy of Engineering Physics (CAEP). The FP-1 facility is a pulsed power driver which could generate high amplitude magnetic field to drive metal liner imploding. Convergent shock wave was generated by impacting a magnetic-driven aluminium liner onto a inner mounted tin liner. The convergent evolution of the disturbance pre-machined onto the tin linerʼs inner surface was diagnosed by x-radiography. The spike amplitudes were derived from x-ray frames and were compared with linear theory. An analytical model containing material strength effect was derived and matched well to the experimental results. This sensibility of the disturbance evolution to material strength property shines light to the application of Richtmyer–Meshkov instability to infer material strength.

Simulation Study on Expansive Jet Formation Characteristics of Polymer Liner

An ideally shaped charge warhead is an effective weapon against armored targets. The use of the gathering energy effect generated by the explosion drives the liner to form a shaped charge jet, which can penetrate the armored target. Existing shaped charge warheads often use a metal liner. Herein, we discuss the characteristics of polymer liners. To study the characteristics of the expansive jet formed by the polymer liner, three polymer materials with different properties—polytetrafluoroethylene (PTFE), nylon (PA), and polycarbonate (PC)—were selected. Using the smooth particle hydrodynamics (SPH) method and the AUTODYN finite element software, the expansive jet formation by the polymer liners was simulated and verified by experimental data. The polymer jets of the different materials exhibit a certain degree of expansivity; however, due to differences in the material properties, the expansive diameter of the jet and the degree of head compaction differed. The expansive diameter of the PA jet was the smallest, and that of the PTFE jet was larger than that of the PA jet, but with a smaller compactness. The PC jet exhibited the largest expansive diameter and the highest degree of compactness.

Tensile and Fracture Properties of Commercially Pure Titanium (CP-70) Hemispherical Forgings

Commercially pure (CP-70) titanium is used as the metallic liner for composite overwrapped pressure vessels used in satellite launch vehicles. The metallic liner is fabricated from domes machined out of CP-70 titanium forgings. During the hot closed-die forging of CP-70 domes from billets, the amount of deformation varies location to location, due to the non-uniform flow of material in the die cavity. This non-uniform strain distribution in the hemispherical dome results in microstructural variations along the forging axis which will remain even after annealing. The aim of the present work is to study the tensile properties, impact strength and fracture toughness of CP-70 hemispherical forging in annealed condition from top end to bottom end of domes in radial and circumferential directions with a view to understand the variation in mechanical properties to asses the design margin. Study revealed significant amount of the work-hardening difference within a forged dome even after annealing.

Effect of Hydrogen Refueling Parameters on Final State of Charge

The state of charge (SOC) is a key indicator to show whether a compressed hydrogen tank meets refueling requirements, so it is worth to study effects of the refueling parameters on it. A new SOC analytical solution is obtained based on a simple thermodynamic model. By applying a mass balance equation and an energy balance equation for a hydrogen storage system, a differential equation was obtained. An analytical solution of hydrogen temperature was deduced from the solution of the differential equation, then an analytical solution of hydrogen mass was further deduced based on the analytical solution of hydrogen temperature with some mathematical modifications. By assuming the hydrogen density inside the tank is uniform, the SOC, which defined as a ratio of hydrogen density to the full-fill density, can be transformed to be the ratio of hydrogen mass to the full-fill mass. The hydrogen mass can be calculated from analytical solution of hydrogen mass, while the full-fill mass is supposed to be a constant value. The full-fill density of 35 MPa and 70 MPa tanks at 15 °C are respectively 24.0 g/L and 40.2 g/L, and if the volume of the tank is known, the full-fill mass can also be calculated. The analytical solution of SOC can be unitized to express the reference data, the contributions of inflow temperature and mass flow rate on SOC are presented for a Dynetek type III tank (40 L, metallic liner) and a Hexagon type IV tank (29 L, plastic liner). In addition, the two-parameter effect of inflow temperature and mass flow rate on SOC are presented. The Nusselt number and Reynolds number are utilized to modify the analytical model, the relationship between SOC and refueling parameters can be obtained through the method of fitting. The fittings show a good agreement. The SOC can be determined from the refueling parameters based on the model with more physical meaning. The method developed in this research can be applied to the control algorithm of refueling stations to ensure safety and efficiency.

Experimental study of the strength and durability of metal-composite high-pressure tanks

The results of unique experimental studies of the strength and service life of a metal-composite high-pressure tank are presented. The goal of the study is to analyze the fracture mechanisms and evaluate the strength characteristics of the structure. The methodology included tests of full-scale samples of the tank for durability under short-term static, long-term static and cyclic loading with internal pneumatic pressure. Generalized test results and data of visual measurements, instrumental and acoustic-emission control of deformation processes, accumulation of damages and destruction of full-scale tank samples are presented. Analysis of the strength and stiffness of the structure exposed to internal pneumatic pressure is presented. The types of limiting states of the tanks have been established experimentally. Change in the stress-strain state of the tank under cyclic and prolonged static loading is considered. Specific features of the mechanisms of destruction of a metal-composite tank are determined taking into account the role of strain of the metal liner. The calculated and experimental estimates of the energy potential of destruction and the size of the area affected upon destruction of the tank are presented. Analysis of test results showed that the tank has high strength and resource characteristics that meet the requirements of the design documentation. The results of the experiments are in good agreement with the results of numerical calculations and analysis of the stress-strain state and mechanisms of destruction of the metal-composite tank.

The output of a shock wave on the inner surface of a cylindrical liner

The results of the experimental investigations of the dynamics of the axisymmetric compression of a metallic liner are presented in this work. The studies were carried out using a high-speed camera with nanosecond resolution. It is shown that the detonation wave formed by the multipoint initiation method has a complex three-dimensional cellular structure, where first-order node lines and second-order nodes are present. The hydrodynamic instabilities formed upon the exit of the shock wave onto the inner surface of a metallic liner do not smooth out as they contract, but increase.

Creating and Applying Antifriction Bearing Wood–Metal Materials

Methods of improvement of the tribotechnical characteristics of composite materials, wood–metal, obtained by the introduction of optimization phases in a wood base are given. The proposed and investigated schemes and methods of forming antimic innovative wood–metal bearings with the use of modified timber and metal particles, made of various antifriction materials, are shown. Ex-plateruena under the action of high temperatures, i.e., heat storage fillers made in the form of capsules filled with a fusible alloy, are also proposed for wood–metal liners. The tribological capabilities of the new wrapped wood–metal liners consisting of successive layers of thermally conductive mesh or tape and wood veneer are studied.

Microparticles and plasma stream registration during cylinder compression of a metal liner

In this paper, the authors show the possible way of registration of the microparticles and plasma jets escaping from the inner surface of metal cylindrical liner when the detonation wave reaches it. The liner is allocated within experimental setup and is compressed by detonation products. Jets have been registered by Langmuir gauge which connection circuit was developed by the authors. The authors also developed a technique a method for detecting the signal under study. Average particle (about 4 km/s) and plasma (about 7 km/s) jet velocity is estimated by using the developed technique for copper liner compressed by detonation products. The results of this experiment correlate with those for plane setup.

Penetration behavior of reactive liner shaped charge jet impacting thick steel plates

Reactive liner shaped charge jet (RLSCJ) penetrates thick steel plate by experiments and model analysis combined. The experimental reactive material liners with a density of about 2.3 g/cm3, composed of mass matched ratios of Al/PTFE powders, are consolidated by a cold pressing/sintering process. Four standoffs of 0.5, 1.0, 1.5, and 2.0 CD (charge diameter) are selected to conduct the penetration experiments. The experimental results show that, compared with traditional metal liner shaped charge jet against thick steel plates, a relative larger hole diameter but lower depth accompanying with fragmentation effects of penetrating steel plates are produced by RLSCJ. To understand this penetration behavior of reactive jet, an analytical model is developed to discuss the influence of initiation delay time of reactive jet and standoff on penetration depth. Analysis shows that the penetration depth strongly depends on initiation delay time of reactive jet. With increasing the initiation delay time, the penetration depth increases significantly, showing a good agreement with the experiments. Moreover, to further understand the fragmentation mechanism effect of the thick steel plates, the effective mass of reactive jet inside the penetrating hole and its deflagration-induced structural damage effect are analyzed theoretically. Prediction results fit well with the experiments, including crack generation and propagation in the thick steel plates, and the number of fragments.

Development of the method for estimating serviceability of equipment for the transportation of compressed natural gas

To ensure safe transportation of compressed natural gas, we proposed, based on the results of studies conducted, the algorithm for a method for the evaluation of combined type tanks. The method implies determining parameters of the state of gas in the process of filling a tank, taking into consideration heat exchange processes and evaluation of the stressed-strained state of the tank, considering the operating conditions and the results of technical inspection. To implement the method, the tools for detecting and determining the shape and dimensions of probable corrosive damages of the metal liner surface under the composite shell were used. It was proposed to assess the stressed-strained state of tanks, taking into consideration the operating conditions, through the development and analysis of relevant models. The possibility of obtaining reliable results in the presence of available mechanisms was proved by our own research into the patterns of loading and unloading processes. To verify correctness of construction of the simulation model at the stage of studying the stressed-strained state of the tank with consideration of the actual operating conditions, we proposed the mathematical model that takes into consideration conditions for the interaction between elements of the structure, the effect of internal gas pressure and temperature. The use of the model decreases the costs of experimental research and contributes to ensuring the reliability of simulation results. The advantage of this method is determining the estimated destruction pressure of the combined type tanks at the current state of the dangerous areas and the influence of operating conditions. The practical significance of the obtained results is determined by the possibility of their application to ensure serviceability at the design stage and when tanks are in operation.

Inverse Schultertotalendprothese bei Rotatorenmanschettendefektarthropathie

In aprogredient rotator cuff tear with tendon retraction, fatty infiltration and atrophy of rotator cuff muscles the humerus cannot be centered and stabilized sufficiently in the glenohumeral joint. This leads to rotator cuff defect arthropathy as an eccentric osteoarthritis with acetabularization and wear of the acromion, as well as of the glenoid. Apainful pseudoparalysis of the shoulder indicates the implantation of areversed total shoulder arthroplasty (rTSA) to reduce pain and restore active motion. The rTSA improves the motoric function of the deltoid muscle by medialization and caudalization of the center of rotation via an optimized lever arm and is also indicated in cranio-caudally centered osteoarthritis with static posterior humeral decentration due to abi-concavely eroded glenoid. Currently, humeral anatomical resection with an inclination of 135° and ahumeral retrotorsion of 20-40°, in rTSA in contrast to 155° inclination, has been shown to lead to better glenohumeral motion without loss of stability. Additionally, a reduced glenohumeral offset should be restored by especially bony lateral augmentation of the glenoid. In apre-operatively positive lag sign for external rotation caused by arupture of the infraspinatus/teres minor tendon, alateral latissimus/teres major muscle tendon transfer in rTSA can optimize active external rotation. The tendon of the subscapularis muscle should be re-fixated in the deltopectoral approach for rTSA whenever possible for better anterior stability of the glenohumeral joint. Larger diameters of the glenospheres have been shown to have more stability and better motion. Humeral metaphyseal metal liners with corresponding polyethylene glenospheres can avoid osteolysis of the inferior scapular neck caused by polyethylene debris due to impingement of the humeral liner at the scapular neck.

Structural health monitoring of composite pressure vessels using guided ultrasonic waves

Composite pressure vessels are important components in the storage of gases under high pressure. Among others, a common type of pressure vessel is made of a metal liner overwrapped with a fibre-reinforced plastic material. Conventional hydrostatic tests, used to assess the integrity of pressure vessels, may overstress the material and thus reduce the remaining lifetime of the tested component. Therefore, a truly non-destructive structural health monitoring (SHM) system would not only ensure a safer usage and extended lifetime, but also remove the necessity for periodic inspection and the testing of pressure vessels. The authors propose the use of guided ultrasonic waves, which have the potential to detect the main damage types, such as cracking in the metal liner, fibre breaks and composite matrix delamination. For the design of such an SHM system, multimodal ultrasonic wave propagation and defect-mode interaction must be fully understood. In this paper, simulation results obtained by means of finite element modelling (FEM) are presented. Based on the findings, suggestions are made regarding appropriate wave modes and their interaction with different flaw types, as well as the necessary excitation and suitable sensor configurations. Finally, a first approach for a reliable SHM system for composite pressure vessels is suggested.

Hydrogen damage in 34CrMo4 pressure vessel steel with high tensile strength

Various efforts have been made to improve the safety of high-pressure gas cylinders for hydrogen or natural gas with high strength steel liners. Metal liners with high tensile strength have a safety concern, particularly with hydrogen gas or hydrogen generating environments. The hydrogen can permeate into the liner material, and make the material brittle, causing hydrogen damage. This study investigated resistance to hydrogen damage for two kinds of 34CrMo4 steel with different strength levels. Hydrogen was charged with the electrochemical method, and the material strength was measured by the small punch testing technique. Hydrogen concentration of the specimen was also measured for every testing condition, with various charging periods. The specimens with high tensile strength absorbed more hydrogen than the regular tensile strength specimens. The absorbed hydrogen caused internal damage of intergranular cracking and blistering. Material ductility at failure decreased, as the hydrogen concentration of the specimen increased. But the hydrogen concentration had virtually no effect on the strength of the materials with hydrogen. These results confirm that the susceptibility to hydrogen damage of the high tensile strength materials is much higher than that of the materials with regular strength. If the metal liner of a hoop-wrapped cylinder vessel of type II has high tensile strength, general corrosion at the liner surface can cause a hydrogen rich environment, and the cylinder can suffer hydrogen damage and embrittlement. Therefore, controlling the strength level under an optimal level is critical for the safety of a cylinder made with 34CrMo4 steel.

Self-Healing of a Confined Phase Change Memory Device with a Metallic Surfactant Layer.

Understanding and possibly recovering from the failure mechanisms of phase change memories (PCMs) are critical to improving their cycle life. Extensive electrical testing and postfailure electron microscopy analysis have shown that stuck-set failure can be recovered. Here, self-healing of novel confined PCM devices is directly shown by controlling the electromigration of the phase change material at the nanoscale. In contrast to the current mushroom PCM, the confined PCM has a metallic surfactant layer, which enables effective Joule heating to control the phase change material even in the presence of a large void. In situ transmission electron microscope movies show that the voltage polarity controls the direction of electromigration of the phase change material, which can be used to fill nanoscale voids that form during programing. Surprisingly, a single voltage pulse can induce dramatic migration of antimony (Sb) due to high current density in the PCM device. Based on the finding, self-healing of a large void inside a confined PCM device with a metallic liner is demonstrated for the first time.

Thermoelastic stress analysis in composite cylindrical vessel with metallic liner using first-order shear deformation theory and differential quadrature method

In this study, thermoelastic stress analysis in composite metal cylindrical vessel is investigated with the help of two theories, first-order shear deformation theory (FSDT) and layerwise theory, using differential quadrature method (DQM). Hamilton principle and FSDT are employed for derivation of the principle differential equations. DQM and Newmark’s methods are used for stress analysis of a composite metal cylindrical vessel subjected to internal dynamic pressure and thermal load achieved from experimental test. In order to more accurately estimate the thickness effect, the layerwise theory is applied to approximate the temperature field. In this solution method, DQM is used to discretize the resulted governing equations while Newmark’s method is implemented to solve the problem in the time domain. It was observed that the fast convergence rate of the DQM method and its accuracy is confirmed by comparing the results with those obtained using ABAQUS software and also with the exact solutions. Furthermore, it was achieved significantly less computational efforts of the proposed approaches with respect to the finite element method.