External Hydrostatic Pressure Research Articles

Pressure-induced magnetic and topological transitions in non-centrosymmetric MnIn2Te4

In recent years, the study of magnetic topological materials, with their variety of exotic physics, has significantly flourished. In this work, we predict the interplay of magnetism and topology in the non-centrosymmetric ternary manganese compound MnIn2Te4under external hydrostatic pressure, using first-principles calculations and symmetry analyses. At ambient pressure, the ground state of the system is an antiferromagnetic insulator. With the application of a small hydrostatic pressure (∼0.50 GPa), it undergoes a magnetic transition, and the ferromagnetic state becomes energetically favorable. At ∼2.92 GPa, the ferromagnetic system undergoes a transition into a Weyl semimetallic phase, which hosts multiple Weyl points in the bulk. The presence of non-trivial Weyl points have been verified by Wilson bands computations and the presence of characteristic surface Fermi arcs. Remarkably, we discover that the number of Weyl points in this system can be controlled by pressure and that these manifest in an anomalous Hall conductivity (AHC). In addition to proposing a new candidate magnetic topological material, our work demonstrates that pressure can be an effective way to induce and control topological phases, as well as AHC, in magnetic materials. These properties may allow our proposed material to be used as a novel pressure-controlled Hall switch.

Observation of TLIESST above Liquid Nitrogen Temperature and Disclosure of Hidden Hysteresis in Multiresponsive Hofmann-type Coordination Polymers.

Photoresponsive spin-crossover (SCO) molecules are an important class of bistable magnetic molecules with intriguing potential in device applications. The light-induced excited spin state trapping (LIESST) and the combined application of light and temperature can provide access to the metastable region of the SCO profile. The primary obstacle in utilizing light stimuli is the manifestation of light-induced trappings at extremely low temperatures. Herein, we report two novel multiresponsive 2D Hofmann-type coordination polymers exhibiting light-induced excited spin state trapping above liquid nitrogen temperature (TLIESST = 82 and 81 K). Stimulating the samples in conjugation with light and temperature successfully unveils hysteresis, which is otherwise concealed. Apart from light and temperature, we found that the SCO phenomenon is also responsive to external hydrostatic pressure and exhibits modulation of the hysteresis width and transition temperature shifts with changes in pressure.

Buckling and vibro-acoustic behavior analysis of laminated immersed cylindrical shells with hydrostatic pressure based on Chebyshev-Fourier spectral approach

The buckling and vibroacoustic behaviour of laminated cylindrical shell structures is vital for the safety and operational efficiency of underwater vehicles. This paper introduces a Chebyshev-Fourier spectral approach for the comprehensive analysis of buckling and vibro-acoustic behaviour in water-immersed laminated cylindrical shells under external hydrostatic pressure. The approach combines Chebyshev polynomials and Fourier series to approximate the displacement of shell and acoustic pressure of the fluid-structure-interaction (FSI) surface in cylindrical coordinates. An approximate solution is used in the axial direction, while an analytical solution is used in the circumferential direction, allowing for the analysis of different circumferential wave numbers n. The influence of external fluid pressure is characterized through the Helmholtz boundary integral equation, while the effect of hydrostatic pressure is deduced using linear elastic theory. From a theoretical derivation standpoint, hydrostatic pressure leads to a reduction in equivalent stiffness, while the external fluid contributes to an increase in the effective mass matrix. Validated against established literature analysis, the study finds that hydrostatic pressure decreases the natural frequencies, though the impact is less significant for lower circumferential wave numbers. For these lower wave numbers, the overall radiated sound power remains largely independent of external hydrostatic pressure, regardless of being in air or water. However, at higher circumferential wave numbers, the effect is more pronounced. This study not only advances the theoretical framework for analysing submerged cylindrical shells but also provides crucial insights into designing more robust structures for underwater applications.

A theoretical analysis of the effect of hydrostatic pressure on cerium oxide for renewable energy applications

The characteristics of cubic cerium oxide (CeO2) have been investigated using density functional theory (DFT) using the PBE-GGA exchange–correlation functional. This study mainly focused on the structural, elastic, and optoelectronic properties of the CeO2 under the application of external hydrostatic pressure. It is observed that lattice constants and volume tend to decrease with increasing pressure. Based on the observed trends in lattice constants variations, CeO2 exhibits compressibility at high-pressure conditions, although it remains structurally unchanged throughout the pressure range of 0 to 100 GPa. Applying pressure within the range of 0 to 100 GPa reveals a distinct characteristic associated with the emergence of electronic bandgap opening. The material displays an indirect energy bandgap, with its magnitude increasing from 2.659 eV to 4.055 eV under rising pressure. To deeply understand the impact of external pressure on the optical behaviour of CeO2, extensive investigation has been conducted on several optical parameters such as the dielectric function, refractive index, optical reflectivity, absorption coefficient, optical conductivity, and loss function throughout the energy range up to 50 eV. However, there is a tendency for optical parameters to show sharpening peaks that shift somewhat towards higher energies. Furthermore, we have also tested the impact of bandgap modulation induced in CeO2 by proposing a CsSnBr3-based solar cell with the One-Dimensional Solar Cell Capacitance Simulator software. Based on our findings, the use of cubic cerium oxide may find its potential to enhance the performance of optoelectronic and renewable energy devices.

Exploring structural and dynamic characteristics of supercooled liquid silver under varying hydrostatic pressures: A molecular dynamics investigation

This study employs molecular dynamics simulations using the embedded-atom method to investigate the structural and dynamic properties of supercooled liquid silver (Ag) metal under varying external hydrostatic pressures ranging from 0 to 70 GPa. The investigation spans various length scales, analyzing short-to-medium-range order, crystalline order, and fractal dimension to discern patterns that indicate how increased pressure affects atomic arrangements. The results suggest that increased external hydrostatic pressure triggers a shift to more ordered atomic structures characterized by relative atomic positions corresponding to the fcc lattice structure, highlighting the system's heightened sensitivity to pressure conditions. Furthermore, the study reveals pressure-dependent changes in atomic diffusion behavior and shows a reduction in atomic mobility with increasing pressure. In particular, the values of the diffusion coefficient decrease from 3.719 × 10−8 to 1.564 × 10−9 cm2 s−1 for 0 and 70 GPa, respectively, demonstrating the direct influence of pressure on the dynamics of supercooled liquid Ag metal.

A First-Principles Study of the Structural, Elastic, and Mechanical Characteristics of Mg2Ni Subjected to Pressure Conditions

This study employs first-principles calculations to examine structural, elastic, and mechanistic relationships of Mg2Ni alloys under varying conditions of pressure. The investigation encompasses Young’s modulus, bulk modulus, shear modulus, Poisson’s ratio, and anisotropy index, as well as sound velocity, Debye temperature, and related properties. Our findings indicate that the lattice parameters of Mg2Ni in its ground state are in agreement with values obtained experimentally and from the literature, confirming the reliability of the calculated results. Furthermore, a gradual decrease in the values of the lattice parameters a/a0 and c/c0 is observed with increasing pressure. Specifically, the values for C13 and C33 decrease at a hydrostatic pressure of 5 GPa, while C11 and C13 increase when the external hydrostatic pressure exceeds 5 GPa. All other elastic constants exhibit a consistent increasing trend with increasing pressure between 0 and 30 GPa, with C11 and C12 increasing at a faster rate than C44 and C66. In the 0–30 GPa pressure range, Mg2Ni satisfies the mechanical stability criterion, indicating its stable existence under these conditions. Additionally, the Poisson’s ratio of Mg2Ni consistently exceeds 0.26 over a range of pressures from 0 to 30 GPa, signifying ductility and demonstrating consistency with the value of B/G. The hardness of Mg2Ni increases within the pressure range of 0–5 GPa, but decreases above 5 GPa. Notably, the shear anisotropy of Mg2Ni exhibits greater significance than the compressive anisotropy, with its anisotropy intensifying under higher pressures. Both the sound anisotropy and the Debye temperature of Mg2Ni demonstrate an increasing trend with rising pressure.

Assessment of non-linear critical pressure of MWCNT reinforced hybrid sandwich semi-ellipsoidal dome under hydrostatic pressure: A numerical and experimental study

The present study involves the numerical and experimental buckling response of MWCNT reinforced composite sandwich semi-ellipsoidal dome subjected to uniform hydrostatic external pressure. The skin of the composite sandwich dome is made up of MWCNT-GFRP composite layers and the PLA honeycomb core, which is reinforced with and without strips. Various honeycomb core configurations, such as SRHC-1 to SRHC-3, are formulated in such a way that the strips are reinforced between the regular honeycomb core in longitudinal and transverse directions to enhance the stiffness characteristics of the structure. The nonlinear buckling analysis of the MWCNT reinforced composite sandwich dome is formulated and solved through the commercially available software ANSYS®. The geometry and material non-linearity of the MWCNT reinforced sandwich dome structures are incorporated in the numerical model while solving the non-linear differential equations and identifying the critical pressure of the sandwich structures using arc length method. The testings were performed to obtain the various mechanical properties, the non-linear behavior of yield stress with a plastic strain of the MWCNT-reinforced GFRP skin and the transverse shear modulus of the various honeycomb core patterns. The efficiency of the present numerical modeling and buckling analysis is confirmed by comparing the critical pressure obtained through the experimental buckling analysis performed on the MWCNT-reinforced prototype sandwich dome and the results available in the literature. Various parametric studies are performed on the MWCNT-reinforced composite sandwich dome to examine the influence of MWCNT reinforcement on the skin, honeycomb core patterns, stacking sequence of skins, aspect ratio and slenderness of the shells and geometric imperfections on the critical pressure.

High pressure phase transition and its influence on structural, mechanical properties and elastic anisotropy of [formula omitted]: An ab-initio study

Lithium carbide (Li2C2), a promising tritium breeding material with potential applications in magnetic confinement-based fusion reactor blankets, has drawn significant attention due to its recent utilization in lithium-ion batteries. In the current study, we employed first-principles calculations with van der Waals (vdW) force correction to explore the structural and mechanical properties of Immm and Pnma phases of Li2C2 subjected to external hydrostatic pressure. It is demonstrated that inclusion of vdW effects accurately predicts Immm→Pnma phase transition at 16 GPa, aligning closely with experimental transition pressure. In contrast, PBE-GGA calculations underestimate the same by about 21%. Current paper is the first comprehensive study of pressure evolution of mechanical properties and strength determining parameters of Li2C2. Interestingly, this inherently brittle material exhibits ductile characteristics beyond 7.5 GPa. The paper also offers a quantitative comparison of its strength parameters with other prominent tritium breeding materials. Finally, the strong directional dependence due to the presence of C2 dimer is investigated by analyzing the pressure variation of elastic anisotropy. The study has its relevance in assessing structural integrity of Li2C2 during inadvertent buildup of tritium and helium that would generate stress in the solid breeder.

Collapse behavior of corrugated stiffened pressure shells under external hydrostatic pressure considering actual fabrication imperfections: A reverse modeling technique

The pressure shell is the most critical load-bearing component in submersible vehicles. It is mainly used to withstand the enormous seawater pressure. In this study, a corrugated stiffened pressure shell was proposed to address the problem of low compression performance of the traditional cylindrical pressure shell. Nine corrugated shells made of aluminum alloy with varying corrugation parameters were created using CNC machining. After welding and sealing treatment, hydrostatic pressure tests were conducted on the shells to investigate the impact of parameters such as wall thickness, number of corrugations, and corrugation height on their compression performance. The shells were measured using a 3D scanner, and the resulting data was used for reverse modeling. The analysis focused on the failure behavior of corrugated shells with geometric imperfections under uniform external pressure using nonlinear finite element analysis. The results indicate that increasing the wall thickness or corrugation height can significantly improve the compression performance of the shells. The position of collapse remains consistent with the location of the maximum Mises stress. Furthermore, it was discovered that the corrugated structure also has an additional advantage in retarding the generation and expansion of diamond-shaped defects on the shell surface. The equilibrium paths of all corrugated shells maintained a smooth and continuous state, demonstrating stable buckling behavior. The numerical calculations were in excellent agreement with the experimental results, highlighting the advantages of the reverse modeling technique. This study provides new insights for the structural design of submarine pressure shells and explores more reasonable and feasible stiffening methods.

Скінченно-елементна модель вертикального резервуара на жорсткій основі

This study addresses the problem of finite element modeling of a 20,000 m3 vertical steel tank subjected to static loads. The structure includes a cylindrical wall of total height 17,880 mm and diameter 39,900 mm. The shell thicknesses of the cylindrical wall are determined according to strength and buckling design standards. The geometric model is axisymmetric. The analysis involves the calculation of the stress and strain fields of the cylindrical wall and the contact zone between the flat bottom and the rigid foundation under various combinations of external loads, namely, excessive and hydrostatic pressures. The ANSYS Mechanical software is used for finite element analysis. Three-dimensional SOLID186 and SHELL281 elements are used for axisymmetric modeling of the shell structure in a three-dimensional formulation. To simulate the contact zone, CONTA174 and TARGE170 finite elements are used to model the moving contact surface of the bottom and the fixed surface of the rigid foundation, respectively. The model is verified by comparing the radial displacements calculated numerically and analytically. The discrepancy does not exceed 4%, thus evidencing the adequacy of the finite element model. The contact zone is analyzed for non-standard service conditions, such an excessive internal pressure in the tank (2.5 and 3 kPa compared to 2 kPa under normal conditions). The unilaterally constrained "bottom–foundation" contact zone model allows the bottom to detach from the foundation, thus leading to contact opening. A full detachment occurs under a certain combination of the excessive and the hydrostatic pressure. For certain liquid levels in the tank, the gap decreases, which may be due to a reduced effect of the excessive pressure. This is accompanied by the development of internal detachment caused by the increasing moment from the hydrostatic pressure. The internal detachment increases the bending moment at the wall–bottom junction, which, under certain conditions, may cause plastic deformations followed by the development of an emergency state.

DFT insights into the pressure-induced ultraviolet to visible band gap engineering of TlMgF3 cubic halide perovskites for optoelectronic applications

The current study utilizes first-principle calculation in order to investigate the geometrical, electrical, mechanical, and optical characteristics of TlMgF3 cubic halide perovskites under the effect of hydrostatic pressure. The interatomic distance is significantly reduced, causing a substantial decrease in the unit cell volume and lattice constant of TlMgF3 perovskite. The electronic energy band gap undergoes a transition from the UV to the visible region in response to the hydrostatic pressure, thereby allowing electron transport from the valence band to the conduction band. This causes some interesting observations in the electronic and optical characteristics of many optoelectronic devices. Additionally, at approximately 500 GPa pressure, the direct band gap is tuned from 4.275 eV to 1.66 eV, making the material suitable for use in solar cell applications. Deep optical analysis has recommended the utilization of TlMgF3 in numerous other applications, including microelectronics, QLED (quantum dot light-emitting diode), OLED (organic light-emitting diode), solar heat reduction materials, and surgical instruments. When external hydrostatic pressure is applied, the mechanical properties of the material are also substantially altered, resulting in increased flexibility and anisotropy.

Mechanical Performance of Bio-inspired Bidirectional Corrugated Sandwich Pressure Shell Under External Hydrostatic Pressure

Mechanical Performance of Bio-inspired Bidirectional Corrugated Sandwich Pressure Shell Under External Hydrostatic Pressure

Collapse of helical cylindrical shells subjected to external hydrostatic pressure

ABSTRACT The present study investigated the collapse performance of helical cylindrical shells subjected to external pressure. Helical cylindrical shells, cylindrical shells, and helically stiffened cylindrical shells were designed, fabricated, geometrically measured, and hydrostatically tested. Linear eigenvalue and nonlinear Riks analyses were performed to evaluate the collapse properties of the fabricated shells. The experimental and numerical results of this study were in agreement. In addition, the existing shapes of shells were used to make a comparison with the helical cylindrical shell. The effects of the spiral rib and wall thickness on the collapse properties of helical cylindrical shells were investigated numerically. The results indicated that a helical cylindrical shell with a spiral cambered surface and spiral rib has considerably higher loading capacity than an ordinary cylindrical shell does. A spiral rib can improve the collapse behaviour of helical cylindrical shells and change their collapse modes.

A novel pressure compensated structure of lithium-ion battery pack for deep-sea autonomous underwater vehicle

The battery pack of deep-sea autonomous underwater vehicle (AUV) is placed in a heavy shell to protect the batteries from external pressure and moisture in a conventional manner. In recent years, the pressure compensated structure with thin film based on oil immersion has been gradually applied to the deep-sea AUV battery pack to achieve lightweight design. In this paper, the ratio of the structural parts of the pressure tolerated and pressure-compensated structures of the cabin to the total weight of the battery pack is systematically analyzed respectively in the depth range of 300– 6000 m, and a new pressure compensated structure with piston based on oil immersion is proposed. The mechanical properties and thermal characteristics of this structure are simulated and analyzed. Finally, the functionality of the compensated structure is verified by the established pressure test platform. The results show that the weight of conventional pressure tolerated structure increases nonlinearly with the increase of hydrostatic pressure to resist external hydrostatic pressure. The proposed pressure compensated structure with piston not only saves at least 18.3 % of the structural component weight at a hydrostatic pressure of 60 MPa, but also reduces the surface temperature of the battery pack due to the presence of dimethyl silicone oil as a pressure transfer medium.

Strength of shellular structures with triply periodic minimal surfaces under external hydrostatic pressure

Strength of shellular structures with triply periodic minimal surfaces under external hydrostatic pressure

Buckling Properties of Water-Drop-Shaped Pressure Hulls with Various Shape Indices Under Hydrostatic External Pressure

Buckling Properties of Water-Drop-Shaped Pressure Hulls with Various Shape Indices Under Hydrostatic External Pressure

Combined effect of rashba spin-orbit interaction, hydrostatic pressure and temperature on energy dispersion based ballistic conductance of InAs tunnel-coupled (double) quantum wire under exterior magnetic and electric field

In this work the change in energy dispersion curve and ballistic conductance for InAs tunnel-coupled double quantum wire (DQWR) under the influence of the external magnetic field, electric field, hydrostatic pressure, temperature, and Rashba spin-orbit interaction (SOI) are studied theoretically in detail. A constant magnetic field transverse to the fundamental plane is applied to the DQWR. The Landuer-Büttiker formalism is used to determine the transport characteristics, and the energy eigenvectors and eigenvalues are derived within the parameters of the diagonalization approach. The numerical results indicate that the energy spectra of the system are influenced by external factors such as magnetic field, electric field, temperature, hydrostatic pressure, and Rashba SOI, resulting in variations in lateral/vertical and downward/upward shifts. These factors also cause oscillatory patterns in ballistic conductance due to the oddity of energy subbands. These results have significant implications for the advancement of double-quantum wire-based devices.

Buckling characteristics of carbon fiber composite/aluminium alloy combined cylindrical shells under external hydrostatic pressure

The buckling behaviour of combined shells fabricated from aluminium alloy and carbon fiber–reinforced polymer (CFRP) composites subjected to external hydrostatic pressure were investigated. Three sets of combined cylindrical shells with different combinations and one set of bare aluminium alloy cylindrical shells were designed and fabricated. The wall thickness of each cylindrical shell was measured. All the cylindrical shells were tested under external hydrostatic pressure, and the buckling load and final collapsed mode were recorded. Numerical models with real imperfections were established, linear and nonlinear analyses were performed to evaluate the buckling loads of cylindrical shells. The experimental and numerical results agreed favourably. On this basis, the effects of the thickness-diameter ratio, combination method and geometric imperfection on the buckling of combined cylinders were studied. This research can provide a reference for the design of combined shells made from CFRP and metal shell.

Experimental investigations on the collapse of spiral-stiffened cylindrical shells under external hydrostatic pressure

This paper presents a comprehensive experimental investigation into the collapse behavior of spiral stiffened cylindrical shells under external hydrostatic pressure. Spiral stiffened cylindrical shells with two different pitches and cylindrical shells were designed and fabricated. The fabricated specimens were divided into three groups. Each group has two identical specimens. Test specimens were welded from stainless steel. The shell was formed by cold bending, and the spiral ribs were welded to the surface of the shell to form a spiral stiffened cylindrical shell. Measurements of initial geometric imperfections and shell thickness were performed on the fabricated specimens to verify the accuracy of fabricating. Subsequently, the specimens were placed in a pressure chamber and pressurized until collapsed to obtain the ultimate collapse pressure and collapse modes. In addition, a uniaxial tensile test was conducted on the shell material to obtain its material properties. Experimental results indicated that the fabricated specimens had excellent repeatability and reasonable precision. The presence of a spiral rib effectively boosted the ultimate collapse pressure of the cylindrical shell with a more pronounced strengthening effect observed as the rib density increased.

Residual strength of corroded ring-stiffened cylinder structures under external hydrostatic pressure

Corrosion damage to submarine pressure hulls is a crucial consideration during the structural design phase because it diminishes the structural strength of a submarine, reducing its operational depth and posing a severe risk to the life of the crew. This necessitates using a validated analytical method to estimate the residual strength and assess the safety of corrosion-affected pressure hulls. This paper presents an experimental and numerical investigation of the residual strength of corroded ring-stiffened cylinders, which are typical components of submarine pressure hulls, the main legs of semi-submersibles, and Floating Offshore Wind Turbine (FOWT) foundations. Four steel ring-stiffened cylinder models were fabricated: two remained intact, whereas the other two were artificially corroded by machining. Hydrostatic collapse tests were conducted in a pressure chamber. To evaluate the effect of initial shape imperfections caused by welding fabrication on the strength of the structure, the initial shape imperfections were measured using a three-dimensional coordinate measuring machine. The experimental results illustrate a significant reduction in the residual strengths of the two damaged models compared with those of the intact models. The collapse processes simulated using the Abaqus software package are presented, demonstrating a close agreement between the experimental results and numerical predictions.