Outer Casing Research Articles

Experimental Investigation of the Axial Load Capacity of Bilateral Helix-Stiffened Cement Mixing Piles in Soft Marine Soil

Bilateral helix-stiffened cement mixing piles (BHCMPs) are a new type of robust composite pile. In this paper, the influence of design parameters, such as the diameter of inner helix plates and the number and size of outer mixing helix plates, on the vertical bearing performance of the pile foundation and the behavior of the pile diameter are investigated through laboratory model tests. The results indicate that incorporating a reverse-mixing process in the pile formation of helix-stiffened cement mixing piles can enhance the overall ultimate bearing capacity and strengthen the soil-cement of the piles. In the case of the same double-blade inner drill pipe, for every 22 mm increase in the blades, its ultimate compressive load-bearing capacity was increased by 10% to 25%, and its pullout load-bearing capacity was increased by 15% to 45%. With further increases in the blades, the percentage increase in the compressive and pullout load-bearing capacity was reduced. With an increase in the number of external mixing blades, its compressive load capacity increased in the range of 5% to 20%, and the elevation load capacity increased in the range of 10% to 25%. Increasing the number of reverse-mixing helix plates on the outer casing enhances the soil-cement strength of the pile body by approximately 15–20% for each additional plate. The average strength of the pile-body soil-cement for each additional plate is estimated to be 1 to 1.4 times that of the previous set, indicating that increased mixing iterations can enhance the perimeter soil-cement strength of the pile. The average bond diameter of soil-cement piles with double-blade internal drilling rods could be seen from the diameter of the piles formed, which was 1.02 to 1.21 times the diameter of the blades.

Recycling primary batteries into advanced graphene flake-based multifunctional smart textiles for energy storage, strain sensing, electromagnetic interference shielding, antibacterial, and deicing applications

Batteries are extensively used owing to their pivotal role in energy storage. However, their adverse environmental impact remains a significant challenge. The prevailing technologies for treating and handling battery waste are remarkably complex and expensive, highlighting the urgent need to upcycle spent battery materials into valuable resources to mitigate their environmental footprint. To that end, this paper reports a scheme for recycling graphite rods and Zn from Zn–C batteries. In this approach, polymeric composites synthesized using graphene flakes extracted from the graphite rods of spent batteries are used to fabricate multifunctional cotton textiles, and the outer Zn case of the spent batteries is employed as a Zn anode in energy storage devices. The synthesized multifunctional fabric shows excellent energy storage performance, particularly in Zn-ion hybrid supercapacitors, achieving a specific capacitance of 140 F g−1 at a scan rate of 0.5 A g−1; an electromagnetic interference shielding efficiency of ∼48 dB; wearable sensing capabilities for human motion detection; and Joule heating behavior for deicing. Moreover, the fabric exhibits remarkable antibacterial efficiency, with an approximately 27-mm-wide inhibition zone against both Gram-positive and Gram-negative bacteria. The “waste-to-wonder” strategy presented herein holds promise for environmental protection and innovative multifunctional textile fabrication.

Archeological analogs for the lifetime prediction of the canister for spent nuclear fuel in the deep geological repository: Part II. Evolution of the corrosion rate over time

AbstractThis work focused on evaluating the evolution of the corrosion product layer and associated corrosion rates on archeological artifacts from 16 sites. Sites with clay soils and maximum waterlogging (pond bottoms and wetlands) were monitored. The corrosion products were evaluated by X‐ray imaging, X‐ray diffraction, scanning electron microscope, Brunauer–Emmett–Teller, and nanoindentation. Two stages of corrosion attack with slightly different mechanisms were observed. Corrosion rates observed at sites with continuous flooding show average corrosion rates of 0.4–1 μm.a−1. These values demonstrate a minimum service life of the container outer case of 15 × 103 years, which is several times longer than the required lifetime of the outer case.

A Study on Cruelty Faced by Silkworms in the Production of Silk

Silk is the fiber that silkworms weave to make their cocoons which are the outer casings that protect them during the pupal stage. But most of the insects used by the silk industry don’t live past this stage, because they are boiled or gassed alive inside their cocoons, which causes the cocoons to begin unraveling so that workers can obtain the silk threads. Some 6,600 silkworms are killed to make just 1 kilogram of silk. The CSB (Amendment) Act, Rules and Regulations have been notified by the Govt. of India to bring quality standards in silkworm seed production. The objective of the research is to create awareness on the cruelty faced by silkworms in the production of silk. The research method used is empirical research and simple random sampling method is used and the sample size is 200 responses and the sample frame is in and around Valluvar kottam. The independent variables are age, gender, education qualifications, occupation and locality. The alternative to this cruel practice is to use another method of obtaining silk called ahimsa silk or wild silk, it is a method of nonviolent silk breeding and harvesting. Wild silk moths are bred, rather than the domestic variety. Roughly 3,000 silkworms are killed to make a single pound of silk. That means that billions, if not trillions, of them are killed for this every year. In order to avoid this practice of killing silkworms we should use an alternative type of fabric or use wild silk

Innovative eco-friendly design solutions for energy demands using swirl- induced burner by jets

Addressing the need for innovative burner designs to optimize combustion characteristics and meet energy efficiency goals, this study introduces a novel concept rooted in swirl-induced flames. The proposed burner employs a unique approach to generate air and fuel swirl using four opposing slots in two sets, each set at distinct angles. Incorporating of a channel within the outer casing allows for fine-tuning of entry angles, optimizing the double swirling process. The objective of this research is to enhance combustion characteristics through the implementation of the swirl principle, introducing a tangential velocity component to the airflow or fuel-air mixture upon entry into the burner. Systematic measurements at various entry angles (0°, 15°, 30°, 45°, and 60°) are conducted to identify optimal or near-optimal conditions. The research covers a comparison between flow fields generated by traditional swirled vanes and swirl-induced injection ports at identical inlet conditions, revealing enhanced flame stability and combustion efficiency in the latter configuration. The formation of recirculation zones around the burner, facilitated by increased outer air jet velocities, promotes better mixing and stability. This research contributes valuable insights into burner design and optimization, with implications for improved combustion efficiency and environmental sustainability.

Unlocking the potential of depleted dry batteries: A dual-purpose approach for waste mitigation and sustainable energy production

Electronic-waste (e-waste) poses a serious environmental challenge due to the increasing consumption and disposal of electronic devices. In the present work a novel method is proposed to repurpose e-waste and bio-waste into a single-chamber and mediator-less microbial fuel cells using dead, non-rechargeable D-type dry batteries. The carbonaceous material inside the dry batteries was replaced with kitchen waste sludge, which served as the substrate. The outer zinc casing was also reused as the anode and the carbon rod as the cathode. Treating the kitchen waste sludge with dilute nitric acid improved the performance of the microbial fuel cells by enhancing the biodegradability and conductivity of the substrate. The untreated microbial fuel cells produced a maximum power density of 15.0 mW/kg at a maximum current density of 50.0 mA/kg, while the treated microbial fuel cells achieved 67.0 mW/kg at 178.0 mA/kg. The main mechanism behind the working of the device is the combined action of galvanic and microbial processes, which synergistically generate electricity from e-waste and bio-waste. Moreover, when four treated microbial fuel cells were connected in series, a high open circuit voltage of 3.3 V was achieved. These microbial fuel cells stand out as eco-conscious and lightweight alternatives to conventional dry batteries, presenting an environmentally sustainable solution for waste management and clean energy production.

Dynamic simulation of double-cased perforation in deepwater high temperature and high-pressure oil and gas wells

In order to ensure the penetrability of double-cased perforation in offshore oil and gas fields and to maximize the capacity of perforation completion, This study establishes a dynamic model of double-cased perforation using ANSYS/LS-DYNA simulation technology. The combination of critical perforation parameters for double casing is obtained by studying the influencing factors of the jet-forming process, perforation depth, diameter, and stress changes of the inner and outer casing. The single-target perforation experiments under high-temperature and high-pressure (HTHP) conditions and ground full-scale ring target perforation tests are designed to verify the accuracy of numerical simulation results. The reduced factor is adopted as the quantitative measure of perforation depth and diameter for different types of perforation charge under different conditions. The results show that the perforation depth reduction increases with temperature and pressure, and the reduced factor is between 0.67 and 0.87 under HTHP conditions of 130 °C/44 MPa and 137 °C/60 MPa. Comparing the results of the numerical simulation and the full-scale test correction, the maximum error is less than 8.91%, and this numerical simulation has strong reliability. This research provides a basis for a reasonable range of double-cased perforation parameters and their optimal selection.

Mach number influence on low-pressure turbine flutter

The effect of the Mach number on the vibration amplitude trends of an isolated low-pressure turbine rotor is described. The study utilizes an analytical model correlating the aerodynamic work and the dry-friction work. Aerodynamic damping has been obtained using a frequency domain linearized Navier-Stokes solver, whereas friction damping has been modeled using a heuristic micro-slip model calibrated with the experimental data. In order to validate the analytical predictions, an extensive experimental campaign was conducted. Unsteady pressure transducers flushed mounted in the outer casing, one chord downstream of the trailing edge of the rotor, were used to characterize the vibration of the rotor. The analysis reveals a significant influence of the Mach number on the work balance between aerodynamic and mechanical components. It is observed that the vibration amplitude and the flutter-induced unsteady pressure perturbations of low-pressure turbine rotor blades notably increases when the exit Mach number does.

Research on the influence of geological factors on casing stress in casing-in-casing cementing in the horizontal section of shale gas wells

Deep shale gas development has great potential, but the frequent occurrence of shale gas well casing change problems triggered by geological factors seriously restricts deep shale gas development. In order to investigate the influence of geological factors on the casing stress of the cemented casing in the sleeve, a model of formation-cement sheath-double casing assemblage was established, and the influence of three-way geostress and fault slip on the casing stress of the casing-in-casing cementing was investigated by using finite element analysis. The results show the following: the smaller the difference between the vertical geostress and the maximum horizontal geostress is, the lower the equivalent force on the casing is, and when the difference gradually decreases from 20 to 7 MPa, the maximum equivalent force of the inner casing under fracturing condition decreases by 9.4%; the increase of the minimum horizontal geostress leads to the increase of the equivalent force of the inner and outer casing. When the minimum horizontal stress gradually increases from 80 to 90 MPa, the maximum equivalent force of the inner casing under fracturing condition increases by 5.9%. The larger the fault slip and the fault angle, the larger the equivalent force generated on the casing. The shear resistance of the double-layer casing is significantly greater than that of the single-layer casing, with an average increase in fault slip distance that can be withstood of about 45.25% and 40.2% in the no internal pressure and fracturing conditions. The larger the casing steel grade and the thicker the wall thickness, the higher the shear resistance. It is recommended to reduce placing of wells in areas where the difference between the vertical and maximum horizontal ground stresses is large, and at locations where the fault slip angle is large, and to use both higher steel grades and larger wall thicknesses of casing. This research result demonstrates the feasibility of “milling + casing-in-casing” technology in severe casing change wells and also provides useful guidance for the application of this technology in the field.

Insights on electromagnetic field distribution due to a vertical electric dipole source inside an infinite steel casing

Energized vertical steel casings have been developed to excite and monitor changes in the electrical properties of resistivity anomalies associated with hydrocarbon production and [Formula: see text] injection, among other applications. Accordingly, the spatial distribution of the fields expected in the medium surrounding a casing source has received considerable attention. However, investigations of the in-borehole distribution of the fields, currents, and charges have been lacking. Such an analysis is the objective of this work. Inside the borehole, the electric field is dominantly vertical, owing to the azimuthal symmetry of the charge density induced at the inner and outer casing boundaries. At the inner surface, charges accumulate dominantly in the vicinity of the source. At the outer surface, charges distribute along the extent of the casing, driven by the vertical channeling and radial leakage of the current flow. Inductive effects arise as the source oscillates in time, effectively resulting in a vanishing flux of azimuthal magnetic field and switching of the sign of the charge density along the vertical extent of the pipe. The alternating charge distribution yields fields propagating inward and outward within the metallic medium, describing inhomogeneous Zenneck surface waves that can interfere as they propagate and superimpose up and down the borehole. In the surrounding medium, the azimuthal magnetic field is driven by the current flowing vertically along the borehole, whereas a dominantly radial electric field is driven by the charge distributed on the outer casing surface.

수중에서의 무게추 중량과 수심의 상관성 조사

This study is one of the basic experiments for the development of a weight type water level gauge. The weights are made of polyvinyl chloride (PVC) with a density of 1.1-1.35 g/cm3, in cylindrical shapes of different sizes. The weights come in different diameters: 5, 6, 7, and 8 centimeters, and two different lengths: 20 and 30 centimeters. The weight of the weights was measured using a load cell and the inverse relationship of weight change with increasing depth was investigated. Also, by adjusting the gap between the weight and the outer casing, the distance at which the error in the weight observation due to the surface tension of water of 72.75 dyne/cm (20℃) was not affected was determined. In conclusion, we found that the larger the diameter of the weight and the smaller the height, the better the correlation with the water depth. Also, considering contamination of the PVC weight and manufacturing precision, it was determined that the space between the PVC weight and the external case required more than 1cm. A buoyancy type water level gauge requires the smallest possible weight diameter and sufficient clearance.

Outer casing structure design for the trisection turbine wheel burst of the air turbine starter.

The aviation regulations mandate that high-energy rotor components must possesses adequate containment capabilities. Ensuring the containment of the turbine wheel of the air turbine starter is of paramount importance. In this paper, the design thickness of the containment ring was determined and the containment ring deformation was given. Based on the design thickness and deformation of the containment ring, an outer casing structure design method was proposed by using FEM. Then, two containment tests were conducted for different distances between the containment ring and outer casing to validate the outer casing structure design method. The errors of the containment ring deformation are smaller than 7.5%, and the experimental results of the containment process are in accordance with the simulation, validating correctness of the outer casing structure design method. The containment ring deformation rate with the design thickness T = 10 mm is 115%. A safety margin of 1.05 is designed by considering the uniformity of containment ring deformation and the containment ring assembly error. The results illustrate that the deformed containment ring does not damage the outer casing, when the inner diameter of the outer casing is designed as 1.2 times the outer diameter of the containment ring.

Comparison of single and multi-coil self-powered MR damper subjected to cyclic and earthquake loading for structural vibration control

A promising solution for semi-active vibration control of different dynamic systems is to use magnetorheological (MR) dampers. In the present study, the investigation focuses on developing a novel single and multi-coil self-powered magnetorheological (MR) damper system using electromagnetic induction (EMI) for seismic mitigation. The conventional MR dampers, which rely on external power sources, can be unreliable and impractical in earthquake-prone locations. Thus, the EMI device connected to the MR damper can be used as an effective and alternative power source for the MR damper, results in a self-powered system. The proposed energy-harvesting system is an MR damper placed above the top of the piston. The coil is wound around the piston, and the outer casing with a ferrite magnet is fixed. As the mechanical energy of the piston is converted into electrical energy, its self-tuning capacity is a perfect fit for structural vibration control applications. The MR damper is subjected to cyclic and time-history loading. At a maximum amplitude of 15 mm, the damper generated 1767.8 N for cyclic loading and -1780 N for earthquake loading, the El Centro earthquake 1940 is considered for the study. By placing EMI, the mechanical energy is converted into electrical energy and powers the damper to avoid external power. The experimental results showcase enhanced damping forces and adaptability, thereby establishing it as an innovative and effective it can be alternative to conventional MR dampers for vibration control in future

Double casing warhead with sandwiched charge: The axial distribution of fragments velocities

The double casing warhead with sandwiched charge is a novel fragmentation warhead that can produce two groups of fragments with different velocity, and the previous work has presented a calculation formula to determine the maximum fragment velocity. The current work builds on the published formula to further develop a formula for calculating the axial distribution characteristics of the fragment velocity. For this type of warhead, the simulation of the dispersion characteristics of the detonation products at different positions shows that the detonation products at the ends have a much larger axial velocity than those in the middle, and the detonation products have a greater axial dispersion velocity when they are closer to the central axis. The loading process and the fragment velocity vary with the axial position for both casing layers, and the total velocity of the fragments is the vector sum of the radial velocity and the axial velocity. At the same axial position, the acceleration time of the inner casing is greater than that of the outer casing. For the same casing, the fragments generated at the ends have a longer acceleration time than the fragments from the middle. The proposed formula is validated with the X-ray radiography results of the four warheads previously tested experimentally and the 3D smoothed-particle hydrodynamics numerical simulation results of several series of new warheads with different configurations. The formula can accurately and reliably calculate the fragment velocity when the length-to-diameter ratio of the charge is greater than 1.5 and the thickness of the casing is less than 20% its inner radius. This work thus provides a key reference for the theoretical analysis and the design of warheads with multiple casings.

Performance Study of Casing Piles in Expansive Soil Foundations: Model Testing and Analysis

This study investigates the critical behavioral characteristics of pile foundations in expansive soil foundations through a series of model tests, including settlement, axial force, and side frictional resistance. The experiment initially utilized sand, bentonite, and gypsum as the fundamental materials for the preparation and composition research of expansive soil simulant materials. Subsequently, the performance of different types of model piles under various loads and water immersion conditions was analyzed. The results indicate that non-cased piles exhibit typical friction pile behavior, while PVC-cased and steel-cased piles effectively reduce side frictional resistance, resulting in a more uniform distribution of axial force along the pile. After immersion, the model test materials experience expansion, with a faster initial expansion rate and a more gradual later expansion rate. Different types of model piles exhibit different displacement characteristics, and the presence of an outer casing can reduce the uplift of the inner pile. Furthermore, PVC casing demonstrates better performance in handling negative frictional effects. This study provides valuable insights for the design and construction of pile foundations in expansive soil foundations.

Cooling Fan Failure Modes to Enable Development of Automotive ECU Fan Health Monitoring System

Electronic control units (ECUs) are widely used in the automotive industry. Recent efforts to enable enhanced and automated driving requires these ECUs to process and execute computationally expensive algorithms. With these developments, the ECUs now have a higher computing power and thus are at a greater risk of overheating. This may limit the availability of the essential functionalities in the vehicle. Currently, high operating temperatures are mitigated using passive cooling, which allows heat to dissipate without expelling any energy; however, more robust methods are required to enable this new technology. A cooling fan system is one of the desired methods for ECU thermal management, as this type of system draws cooler air from outside and expels the warm air from within. Therefore, the fan health status is critical to ensure ECU availability and reliability for vehicle operation, as when the fans become degraded, they cannot maintain the required airflow to minimize the ECU operating temperature. Traditionally, fan failures are detected by monitoring the fan speed versus the commanded duty cycle, thus it is desired to develop a robust health monitoring method for the fans. Fan failure mode study and fault injection can be used to enable the development of prognostics. Investigating the fan failure modes results in two main categories, which are internal and external. External fan failures include degradation and cracking of the outer casing, while internal failures include motor and ball bearing issues. Fault injection methods were developed based on these failure modes while considering potential operating conditions. For example, the fans were exposed to multiple environmental conditions, such as dust, humidity, and heat. These conditions can potentially trigger both internal and external failures. The data collection was conducted with the fans running in a standalone setup, being controlled by external equipment to ensure that the electronic input values were known. After running tests for 30 days, sufficient data was collected to enable degradation modelling. The data will contribute to the development of a predictive algorithm which will estimate the state of health of the fan based on its performance over time. This paper will discuss the failure modes and the data generated through simulation and fault injection.

Analysis of Debonding Failures of the Screen and Case during Tablet Drop

In recent years, due to the increasingly powerful functions of tablets, more and more people have used tablets. The failure of the screen caused by debonding failure between the screen and the case of the tablet due to drops will affect the normal use of the tablet. However, there have been few studies on the debonding methods of the screen and the case of the tablet, as well as the factors influencing the debonding between the screen and the case of the tablet. Numerical analysis software was used in this paper to simulate the iPad Air (Air) drop process, and the cohesive zone model and tiebreak contact were used to simulate the debonding process between the screen and case of the Air tablet, respectively. When the results are compared to the experiments, the results show that the cohesive zone model is superior. The effects of various rounded corner radii, drop postures in the XY plane, materials of the outer case, and strain rates of PC/ABS on the localized debonding between the outer case and outer glass of the Air during the drop process were investigated. The degree of debonding between the Air model’s outer case and outer glass is defined by t, which is the ratio of the area of the deleted cohesive elements to the total area of the cohesive elements. The results show that the rounded corner radius and the strain rate of PC/ABS have less influence on t; the t of the Air model dropped at 45° in the XY plane is 37.7% of that dropped at 0° and 90°; and the t of the Air model with glass as the outer case material is 48% of that with aluminum alloy as the outer case material. These studies serve as a foundation for tablet design and material selection.

Influence of anchored orbicular rings on the performance of sandwich concrete‐filled double‐skin steel tube columns

AbstractSince recent years, double‐skin tube column sections formed from two parallel, concentrically spaced steel casings, with the sandwiched area between the casings packed with concrete infill, have been employed extensively. The cross‐sectional shapes of the inner and outer casings might be the same or different, such as round, square, octagonal, etc. These concrete‐filled double‐skin steel tubular (CFDST) columns act similarly to concrete‐filled steel tubular (CFST) sections but have less self‐weight and better stiffness. The present study evaluated the response of CFDST column stiffened with orbicular rings under axial compression. It consists of inner and outer steel tubes stiffened by orbicular rings near both ends of columns. The orbicular rings were provided at different locations as L/3, L/4, and L/5, and a series of tests were conducted to obtain the performance of CFDST columns stiffened with orbicular rings with regard to the maximum load‐carrying capacity, load–strain behavior, and load‐deformation behavior. Furthermore, a parametric study was conducted by varying the diameter to thickness ratio, hollowness ratio, the thickness of orbicular rings, yield strength, and location of orbicular rings. The results showed that CFDST column stiffened with orbicular rings have higher ultimate load capacity than unstiffened CFDST. Stiffened CFDST with orbicular rings showed more ductile response than CFDST column and helps to improve the outer steel tube's restraint on sandwiched concrete. In order to estimate the load‐bearing capacity of CFDST columns stiffened with orbicular rings under axial compression, an empirical equation was proposed. The experimental results and findings of the suggested equations were found to be in good agreement.

Suitability Analysis of the Deformation Behavior of Metal Corrugated Casing in High-Temperature Wellbore

The stability of the casing is a crucial prerequisite for implementing the in situ high-temperature steam injection method in oil shale reservoirs. In order to address the issues of substantial expansion, concentrated thermal stresses, and susceptibility to damage observed in traditional straight casings under high temperatures, this paper proposes the utilization of a corrugated casing structure. In this regard, to investigate the impact of the shape and structure of the wellbore casing on its mechanical properties, identical corrugated and straight casings were selected and studied. Uniaxial compression and tensile tests were conducted on the casings, along with coordination deformation experiments between the casing and cement sheath under varying temperatures. Numerical simulations were employed to obtain the deformation characteristics of the corrugated and straight casings under axial compression and tension loads, as well as the stress distribution on the outer casing wall. The results showed that when subjected to the same amount of deformation under axial loading, the corrugated casing experienced lower compressive and tensile loads compared to the straight casing. Moreover, under the sole constraint of cement sheath, increasing the temperature led to lower vertical strains (perpendicular to the ground) at all measuring points of the corrugated casing as compared to the corresponding strains in the straight casing. Numerical simulations revealed that, under the same temperatures, the deformation at the interface between the corrugated casing and the cement sheath was smaller, while the vertical stress at the interface of the corrugated casing was also lower than the straight casing. Overall, the corrugated casing, with its corrugated structure that enabled micro-deformation, effectively mitigated the axial deformation of the casing caused by thermal expansion. Consequently, the corrugated casing reduced the extrusion of wellbore casing on the cement sheath, thereby preserving the integrity and stability of the wellbore cementing structure.

Instability evolution of a shock-accelerated thin heavy fluid layer in cylindrical geometry

Instability evolutions of shock-accelerated thin cylindrical SF $_6$ layers surrounded by air with initial perturbations imposed only at the outer interface (i.e. the ‘Outer’ case) or at the inner interface (i.e. the ‘Inner’ case) are numerically and theoretically investigated. It is found that the instability evolution of a thin cylindrical heavy fluid layer not only involves the effects of Richtmyer–Meshkov instability, Rayleigh–Taylor stability/instability and compressibility coupled with the Bell–Plesset effect, which determine the instability evolution of the single cylindrical interface, but also strongly depends on the waves reverberated inside the layer, thin-shell correction and interface coupling effect. Specifically, the rarefaction wave inside the thin fluid layer accelerates the outer interface inward and induces the decompression effect for both the Outer and Inner cases, and the compression wave inside the fluid layer accelerates the inner interface inward and causes the decompression effect for the Outer case and compression effect for the Inner case. It is noted that the compressible Bell model excluding the compression/decompression effect of waves, thin-shell correction and interface coupling effect deviates significantly from the perturbation growth. To this end, an improved compressible Bell model is proposed, including three new terms to quantify the compression/decompression effect of waves, thin-shell correction and interface coupling effect, respectively. This improved model is verified by numerical results and successfully characterizes various effects that contribute to the perturbation growth of a shock-accelerated thin heavy fluid layer.