Laminate Structure Research Articles

A Review on United States Patents to Prevent Mechanical Failures in Foldable Smartphones

Abstract A foldable smartphone is an exciting new approach for future mobile systems. With some early models being introduced to the market, research and development is being performed to increase the reliability of future systems. Mechanical failure of the display is the major source of foldable smartphone's reliability issues. The display is a laminate structure including an organic light emitting diode (OLED) layer (emission layer and pixel electrode layer), a touch panel, a polarizer, and multiple protective layers in addition to multiple functional coatings and supporting structures. The display is exposed to repeated folding, finger touch, and the impact of external sharp objects. In addition, mechanical behavior changes through the thickness of the display; which adds extra challenges in preventing damage to vital components of the display. This review covers more than 100 U.S. patents about the mechanical failures in foldable smartphones published or filed after 2015. Different inventions reviewed are to design a foldable configuration to prevent mechanical failures resulting from the following four mechanisms: (1) plastic deformation (yielding, creep, and fatigue); (2) fracture; (3) delamination; and (4) buckling (warping, buckling, wrinkling, and creasing).

Detecting defects in the main spar of a wind turbine blade

Various defects produced during the manufacture of a wind turbine blade can affect the damage evolution under fatigue loads. In this paper, a calculation model based on energy dissipation was used to predict damage evolution. Based on the structure of the unidirectional laminates in the main spar of a 1.5-MW blade, specimens with voids or delamination defects of different dimensions were fabricated. Fatigue tests of the specimens were monitored with an infrared thermography system. The energy dissipation density was calculated from the surface temperature. A damage parameter D is proposed to represent the degree of damage evolution. By analyzing the energy dissipated during cyclic loading, it is possible to evaluate the critical moment when a defect evolves into initial critical damage. The calculation model agrees well with the observed damage evolution. This innovative method could be used to detect the initial damage in a main spar with defects during a fatigue test.

Finite Element Analysis of Short-edge Distance of Fastener Holes in Composite Laminates

In the production process of aircraft structures, due to design defects or the accumulation of tolerances in part manufacturing and assembly, structural short margins appear at the mechanical joints of composite laminates. In this paper, the analytical method is used to analyze the hole edge stress of the composite material fastener, and the finite element analysis of the short edge distance of the fastener hole of the composite laminate structure is carried out. The hole edge stress and residual net of the structure after the short edge distance. The stress distribution of the cross-section is analyzed to discuss the changes of the stress and strain at the edge of the hole after the short margin of the composite laminate to determine the effect on the strength of the aircraft.

Copper Deposition from Its Sulfate Solution onto Titanium Powder with the Simultaneous Mechanical Activation of the Mixture

To fabricate Cu–Ti composite particles, the method of copper deposition from its sulfate solution on titanium powder particles with the simultaneous mechanical activation (MA) of the mixture in an AGO‑2 planetary ball mill for 5 min is used. The CuSO4 ⋅ 5H2O concentration in solutions is 10 and 16%, which provides molar ratio Cu/Ti = 0.85 and 1.36, respectively, with the complete reduction of copper. The rapid reduction of copper in the form of highly dispersed partially amorphized powder occurs during MA, and composite particles with a thin laminate structure and high reaction ability are formed. Prepared composites are rinsed and stored in argon because reduced copper possesses high activity and rapidly oxidizes in air to oxide Cu2O. After drying, the additional MA of the mixture is performed for 5 min. Pellets 3 mm in diameter and up to 1.5 mm in height are compacted from prepared powders and heated in argon to 700–1200°C. An intense reaction with heat liberation (heat explosion) and the formation of TiCu, Ti2Cu3, and Ti2Cu intermetallic compounds starts upon sample heating. The critical inflammation temperature for composite powders formed by MA with simultaneous copper deposition from the solution is 480°C, which is 400°C below the inflammation temperature of the usual powder mixture of titanium and copper. The alloy has a dendritic structure at a heating temperature close to the melting point, while, if it is exceeded by more than 100°C, the phase distribution in the alloys becomes more uniform and their size decreases.

Metal-cation-modified graphene oxide membranes for water permeation

The stability of graphene oxide (G-O) membranes in water can be enhanced via the simple addition of metal-cations to the planar laminate structure, however, the relationship between valency and hydration radius and the properties and performance of the membrane structure is unclear. This study examines the impacts of adsorbed monovalent (K+ and Na+), divalent (Cu2+ and Mn2+) and trivalent (Al3+, Fe3+ and La3+) cations on permeation for G-O membranes in water vapor permeation and pervaporation. Metal-cations with high electronegativity and a small hydration radius possess greater binding strength that constrains the G-O laminate channels (d-spacing). Both water permeation methods show a positive trend between permeation and interlayer spacing for metal-cations with the same valency. Amongst the different valence states, steric exclusion from cations is dominant for minimal water layers (water vapor permeation), while the ability for cations to attract and hold water molecules inside its outer shell has a greater effect on swollen channels (pervaporation). These findings help pave the road towards G-O based applications in next generation water filtration methods for desalination and wastewater treatment.

Surfactant Intercalated Mono‐metallic Cobalt Hydrotalcite: Preparation, Characterization, and its Bi‐functional Electrocatalytic Application

AbstractA series of surfactants are intercalated into mono‐metallic hydrotalcite type α‐Co(OH)2 through ion exchange method to produce organic‐cobalt hydrotalcite (HT‐SDS, HT‐TMA and HT‐SL). The resultant material maintains its inner laminate structure with increased interlayer spacing. FT‐IR spectroscopic studies and powder XRD analysis revealed the successful intercalation of SDS into the interlayers of α‐cobalt hydroxides. TEM and N2 sorption studies further demonstrate the intercalation of organic surfactant in the interlayer spacing of CoHT. XPS studies indicated the presence of surface exposed cobalt in both Co2+ and Co3+ oxidation states. Furthermore, the applicability of these intercalated materials in electrocatalytic applications specifically for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in alkaline medium is explored. Among the various investigated materials, sodium dodecyl sulphate (SDS) intercalated material exhibited better performance in terms of higher catalytic current at a lower overpotential value. Moreover, the kinetic parameters associated with electrocatalysis are determined, and the mechanism behind OER and ORR is elucidated. These results clearly demonstrate the potential bi‐functional utility of such layered materials for electrocatalytic applications.

Selective actuation and sensing of antisymmetric ultrasonic waves using shear-deforming piezoelectric transducers

Structural health monitoring of thin plate and beam structures using ultrasonic guided wave techniques has been widely studied and demonstrated advanced capabilities dependent on detailed analysis of specific guided wave modes. A common setup employs the d31 electromechanical coupling of piezoelectric wafer active sensors mounted on the surface of a beam or plate. Analysis of output signals from these basic systems is complicated because they represent multiple superposed ultrasonic wave modes that propagate at different velocities, are dispersive, and undergo reflection, refraction, and mode conversion. Multiple techniques have been pursued to overcome this complication. This article presents recent research into the use of shear-deforming lead zirconate titanate piezoelectric transducers, employing the d15 electromechanical coupling property, embedded within beam-like structures to selectively actuate and sense specific ultrasonic wave modes. The internally located transducers actuated and sensed transverse shear, coupled to bending and antisymmetric waves. A combination of results from finite element simulations and experiments found that d15 transducers located at the neutral axis of a beam exclusively coupled to antisymmetric wave modes and did neither directly actuate nor sense symmetric wave modes. Further study was performed to evaluate the effects of off-neutral-axis location on the mode selectivity and found that off axis location of the d15 transducer did not diminish the coupling to antisymmetric wave modes, but introduced coupling to symmetric wave modes. Additional study was performed to assess the ability of structural health monitoring systems employing shear-deforming d15 lead zirconate titanates located at the neutral axis to detect common forms of damage in laminate structures. The combination of selective actuation and selective sensing provides a powerful tool for signal analysis in ultrasonic structural health monitoring of thin plates and beams.

Genesis of Two Types of Carbonaceous Material Associated with Gold Mineralization in the Bumo Deposit, Hainan Province, South China

Carbonaceous material (CM) is common in meta-sediments and is generally interpreted to be intimately associated with gold mineralization. For the Bumo deposit in Hainan Province, South China, CM is mainly hosted by greenschist facies—to amphibolite-facies metamophic rocks of the Paleo—to the Mesoproterozoic Baoban Group, and by auriferous veins which could be used as an important gold prospecting indicator. However, the genesis of CM and its relationship with gold mineralization are still unclear. From the field work and thin section observations two types of CM occur, i.e., layered and veinlet. The layered CM occurred in CM-bearing black shales, up to meters thick, and prevails in the deposit. More importantly, Au-bearing sulfides are commonly distributed along the boundary between the quartz veins and layered CM. In contrast, the veinlet CM, co-precipitated with native gold and sulfides, has the thickness of micro- to centi-meters, and these thin veins occur in quartz veins and hydrothermally altered rocks. In addition, layered CM has a stringy shape and laminate structure, while veinlet CM occurs as isometric particles based on the Scanning Electron Microscope (SEM) analysis. The Raman carbonaceous material geothermometer indicates that layered CM with a high maturity is formed at elevated temperatures of 400–550 °C, consistent with X-ray diffraction (XRD) analysis. In contrast, veinlet CM with a low maturity is formed at 200–350 °C and generally consistent with gold mineralization. In addition, layered CM has δ13C values ranging from −30 to −20%, demonstrating a biogenic origin. Consequently, it is interpreted that layered CM is formed by a pre-ore metamorphic event during Caledonian, and its reducing nature promotes gold precipitation via destabilization of aqueous Au complexes or facilitating sulfidation. Veinlet CM is of hydrothermal origin, and its precipitation modified the chemical conditions of ore fluids, leading to the destabilization of Au complexes, which therefore are favorable for mineralization.

Static Residual Tensile Strength Response of GFRP Composite Laminates Subjected to Low-Velocity Impact

The dependency of the static residual tensile strength for the Glass Fiber-Reinforced Plastic (GFRP) laminates after impact on the impact energy level and indent shape is investigated. In this study, two different laminates, unidirectional, [0°2]s) and TRI (tri-axial, (±45°/0°)2]s), were prepared using the vacuum infusion method, and an impact indent on the respective laminates was created at different energy levels with pyramidal and hemispherical impactors. Impact damage patterns, such as matrix cracking, delamination, debonding and fiber breakage, could be observed on the GFRP laminates by a scanning electron microscope (SEM), and it is found that those were dependent on the impactor head shape and laminate structure. Residual in-plane tensile strength of the impacted laminates was measured and the reduction of the strength is found to be dependent upon the impact damage patterns. Furthermore, in this study, stress concentrations in the vicinity of the indents were determined from full-field stress distribution obtained by three-dimensional Digital Image Correlation (3D DIC) measurement. It was found that the stress concentration was associated with the reduction of the residual strength for the GFRP laminates.

Vibration and Noise Reduction Optimization Design of Mine Chute with Foam Aluminum Laminated Structure

The mining chute is an important equipment in the process of coal transportation and coal screening preparation. During the working process, the mining chute will generate a lot of vibration and noise because of constantly friction and impact of gangue and coal blocks. In order to reduce the vibration and noise during the operation of the chute, a new type of foam aluminum laminated structure is used to manufacture the mining chute. According to the characteristic of chute, the laminated structure is optimization designed by taking the vibration amplitude as the objective function, the thickness of the steel plate and the foam aluminum core plate as the design variables. And then, the vibration and noise reduction performance of two type chutes are carried out by using experiment and finite element simulation method. The results show that the using of foam aluminum laminate structure to manufacture the chute can obviously increase the damping ratio of the system, which can effectively reduce the vibration amplitude of the chute. And the average sound insulation performance of foam aluminum laminated chute is better than prototype chute, especially in the middle and high frequency section, which can be reduced by about 7.1 dB on average comparison with prototype chute. So, it can be seen that the foam aluminum laminated structure chute has a more significant sound insulation and vibration reduction effect than the prototype chute.

Reservoir characteristics and genetic mechanisms of gas-bearing shales with different laminae and laminae combinations: A case study of Member 1 of the Lower Silurian Longmaxi shale in Sichuan Basin, SW China

Based on thin-section, argon-ion polished large-area imaging and nano-CT scanning data, the reservoir characteristics and genetic mechanisms of the Lower Silurian Longmaxi shale layers with different laminae and laminae combinations in the Sichuan Basin were examined. It is found that the shale has two kinds of laminae, clayey lamina and silty lamina, which are different in single lamina thickness, composition, pore type and structure, plane porosity and pore size distribution. The clayey laminae are about 100 μm thick each, over 15% in organic matter content, over 70% in quartz content, and higher in organic pore ratio and plane porosity. They have abundant bedding fractures and organic matter and organic pores connecting with each other to form a network. In contrast, the silty laminae are about 50 μm thick each, 5% to 15% in organic matter content, over 50% in carbonate content, higher in inorganic pore ratio, undeveloped in bedding fracture, and have organic matter and organic pores disconnected from each other. The formation of mud lamina and silt lamina may be related to the flourish of silicon-rich organisms. The mud lamina is formed during the intermittent period, and silt lamina is formed during the bloom period of silicon-rich organisms. The mud laminae and silt laminae can combine into three types of assemblages: strip-shaped silt, gradating sand-mud and sand-mud thin interlayers. The strip-shaped silt assemblage has the highest porosity and horizontal/vertical permeability ratio, followed by the gradating sand-mud assemblage and sand-mud thin interlayer assemblage. The difference in the content ratio of the mud laminae to silt laminae results in the difference in the horizontal/vertical permeability ratio.

Comparative Study of Glass Fiber Content Measurement Methods for Inspecting Fabrication Quality of Composite Ship Structures

A comparative study of glass fiber content (Gc) measurement methods was conducted using actual glass fiber reinforced plastic laminates from the hull plate of a 26-ton yacht. Two prototype side hull plates with the design Gc (40 wt.%) and higher Gc (64 wt.%) were prepared. Four methods were used to study the samples: the calculation method suggested by classification societies’ rules; two direct measurement methods using either calipers and scales or a hydrometer; and the burn-off method, wherein the resin matrix is combusted from the laminates. The results were compared and analyzed to identify the accuracy and benefits of each method. The rule calculation method was found to be effective if the quality of the manufacturing process is known. However, fabrication errors in the laminate structures cannot be detected. Additionally, while direct methods are used to measure the density of glass fibers using measurements of the densities of raw materials and laminates, the volume of inner defects occurring during the fabrication of laminates could not be considered. Finally, it was found that the burn-off method measures Gc and considers the defect volume (voids) inside laminates as well as the non-uniformity of the external shape.

An exploratory study on strengthening and thermal stability of magnetron sputtered W nanoparticles at the interface of Cu/Ni multilayer films

An initial study to investigate the effect of controlled deposition of nanoparticles at multilayer interfaces was conducted to explore the mechanical effect of particles on laminate structures. Nanoparticles with diameter of about 4.5 nm were specifically deposited at the interface between Cu and Ni laminates by forced agglomeration of magnetron sputtered ions using a Mantis Ltd. Nanogen50 nanoparticle generator and the hardness of these films were measured using the nanoindentation technique. Cu/Ni laminates without W nanoparticles have an average modulus value of approximately 120 ± 3.7 GPa and hardness value of 2.23 ± 0.07 GPa, while the hardness values of the particle-containing films are greater, regardless of particle density. The areas with the lowest particle density at the interfaces (0.9 at.% W) show the greatest increase in hardness, with an increase of about 1.3 GPa greater than the particle-free sample. However, as the particle density increases, there is a corresponding decrease in hardness. In-situ x-ray diffraction of these films was also conducted to observe the annealing behavior of these films. For all samples, the Cu and Ni layered structure remained intact; however, there is evidence of Ni diffusion along grain boundaries and interaction with the oxygen, likely creating NiO. After annealing, a significant number of the W nanoparticles dissolved into the Ni matrix to create NiW solid-solution. The ability to deposit particles with such precise control has the potential to open up an exciting new field of research.

Strengthening and ductilization of laminate dual-phase steels with high martensite content

The steels with excellent strength and ductility are expected to be achieved by tailoring the microstructural features. In this work, laminate dual-phase (DP) steels with high martensite content (laminate HMDP steels) were produced by a combination of warm rolling and intercritical annealing. Influence of rolling strain and annealing temperature on the microstructural evolution and mechanical properties of laminate HMDP steels were systematically studied. The strength of HMDP steels was significantly improved to ∼1.6 GPa associated with a high uniform elongation of 7%, as long as the laminate structure is maintained. The strengthening and ductilizing mechanisms of laminate HMDP steels are discussed based on the influence of laminate structure and the high martensite content, which promote the development of internal stresses and can be correlated to the Bauschinger effect as measured by the cyclic loading-unloading-reloading experiments. Detailed transmission electron microscopy (TEM) observation was applied to characterize the dislocation structure in the deformed ferrite.

Synthesis, characterization and electromagnetic absorbing performance of multi-step petaloid morphology VO2(M)

VO2(D) precursor with multi-step petaloid lamination structure was prepared by hydrothermal method, and then VO2(M) sample maintaining similar morphology and geometry with that of as prepared VO2(D) was obtained by subsequent annealing. The XRD Pattern of VO2 (D) precursor and annealed samples at different temperature confirms the formation of required crystalline phases and exposes the presence of other intermediate phases. Surface morphology has been analyzed by SEM characterization, which reveals the variation in petaloid microstructure of the annealed samples at different temperatures. The reflection loss measurement results show that multi-step petaloid laminated structure VO2(M) sample has excellent microwave absorption performance. The sample annealed at 570 °C has the minimum reflection loss value of −37.99 dB at 3.5 mm, and the effective absorption bandwidth (RL < −10 dB) is up to 4.01 GHz at 1.3 mm. Detailed study shows that the excellent microwave absorption performance of the sample results from the combination of its geometry shape/surface polarization, induced loss and resistance loss. In addition, the curvature of the boundary of the laminated structure also affect the microwave absorption performance of the absorber. The discovery of this work effectively broadens the application of VO2(M) and provides a new idea for the design of new absorbing materials with tailored particle morphology.

Formation of sub-wavelength laser induced periodic surface structure and wettability transformation of CFRP laminates using ultra-fast laser

Present work focuses on wettability transformation of carbon fiber reinforced plastic (CFRP) surface by generating micro/nano-structures using a femtosecond laser system. Laser induced periodic surface structures (LIPSS) were realized on carbon fiber (CF) surface at different defocus distances and pulse energies. The hydrophilic CFRP surface obtained just after the laser treatment progressively depicts hydrophobic behavior and further transforming to near superhydrophobic after cleaning followed by vacuum process for 4 h. Scanning electron microscopy (SEM) analysis was performed to capture the generated structure on the carbon fiber surface. Pulse fluence was effective parameters for transition of LSFL to HSFL. The lowest spatial period Λ ≈ 95 ± 6 nm and Λ ≈ 387 ± 15 nm was achieved for HSFL and LSFL, respectively, at 0.3 mJ.

Soft-sediment deformation structures in alkaline lake deposits of Lower Permian Fengcheng Formation, Junggar Basin, NW China: Implications for syn-sedimentary tectonic activity

Soft-sediment deformation structures (SSDS) are an important tool for interpreting paleoseismicity and depositional environments in ancient basin successions. The northwestern margin of Junggar Basin is a key region for understanding the paleogeography and basin attribute of the Junggar Basin during the early Permian. In the Lower Permian (Kungurian) Fengcheng Formation, nine lithofacies are grouped into fan delta, fluvial delta, and shallow, deep and alkaline lacustrine facies associations. Vertical transitions of the sedimentary environments show that the lake basin experienced expansion during deposition of the Lower (P1f1) and Middle (P1f2) members and the shrinkage during the Upper Member (P1f3), which is consistent with the paleogeographic distribution of lithofacies in different members. Conventional cores show a wide variety of SSDS, including ductile (folds, convolute lamination, and load structures), hybrid ductile-brittle, and brittle deformation structures (microfaults, breccias, boudinage and sedimentary dikes). SSDS mainly occurred in a still and deep lacustrine environment. These deformation structures were not formed in any specific lacustrine environment, as there is no difference with the undeformed sedimentary units of the same sedimentary facies. Thus, the triggering mechanism is interpreted as intermittent earthquakes. Lake expansion under arid condition and SSDS intervals with vertical repetition and possible lateral continuity indicate that most seismicity was during the Middle Member (P1f2), corresponding with the main activity on basin-bounding normal faults. The enhanced faulting at this time generated accommodation, creating lacustrine conditions in the basin depocenter. It is thus clear that the early Permian Mahu sag represents an active rift basin with bounding faults, and is not a foreland basin.

The crack displacement prediction of a composite sample by modelling the mixed mode bending test

One of the main failure modes of laminate structures is interfacial failure by interlaminar failure or debonding. Interlaminar failure can be simulated with a model called cohesive zone approach A key ingredient of a cohesive zone approach is a traction-separation law that describes the softening in the crack zone near the tip of interlaminar failure. This simulation utilized the implementation of a cohesive zone approach with traction-separation laws, which implemented within the thin elastic layer feature of the Solid Mechanics interface in a COMSOL Multiphysics analysis software’s on a sample of composite material APC-2/AS-4. The capabilities of the cohesive zone approach to predict mixed mode effect in the beginning and propagation of the crack are demonstrated in a model of mixed-mode bending test. Both load and displacement are measured at the crack interface. The maximum load that carried by the sample used was 257.8 N. Whereas the maximum displacement was 6 mm as a load-displacement curve was shown.

The Nuclear Lamina: Protein Accumulation and Disease.

Cellular health is reliant on proteostasis—the maintenance of protein levels regulated through multiple pathways modulating protein synthesis, degradation and clearance. Loss of proteostasis results in serious disease and is associated with aging. One proteinaceous structure underlying the nuclear envelope—the nuclear lamina—coordinates essential processes including DNA repair, genome organization and epigenetic and transcriptional regulation. Loss of proteostasis within the nuclear lamina results in the accumulation of proteins, disrupting these essential functions, either via direct interactions of protein aggregates within the lamina or by altering systems that maintain lamina structure. Here we discuss the links between proteostasis and disease of the nuclear lamina, as well as how manipulating specific proteostatic pathways involved in protein clearance could improve cellular health and prevent/reverse disease.

Analysis of Oxygen and Nitrogen Redistribution at Interfaces of HfO2 with Laminate TiN/TiAl/TiN Electrodes

The physicochemical nature of the change in the effective work function (EWF) of aluminum doped TiN (using TiN/TiAl/TiN laminate structure) was studied by X-ray photoelectron spectroscopy with high...