Elastic Behavior Research Articles

Mechanisms of near-wellbore fracture growth considering the presence of cement sheath microcracks and their implications on wellbore stability

Placement of intended perforations is usually extensive enough into the reservoir to minimize any near wellbore influence on the expected fracture growth. However, some unplanned fractures do not necessarily originate from the intended shot holes. A sufficient volume of published work exists on the processes of crack growth from the near wellbore regions such as from the cement sheath or from fractures observed on the formation wall surrounding the wellbore. A robust quantification of wellbore stability issues should not detach such fracture development, which can potentially result into issues such as cement sheath damage and unnecessary formation damage in the near-wellbore regions. Such fractures may become fluid injection points during stimulation related wellbore pressurization, leading to pronounced development. In such scenarios, fracture development may become a nuisance if it jeopardises the intended structural support and zonal isolation integrity of the cement sheath around the wellbore, leading to wellbore failure, and a potential abandonment. The pressure transmission across this structural seal affects the zonal isolation integrity and its intended structural support leading to wellbore instability. Understanding crack growth behaviour in such cement-rock structural framework is still illusional yet it poses the wellbore to a risky state of instability. Our study provides insight into mechanical and elastic behavior of a tightly bonded cement-rock framework with presence of initial cracks. It also provides insight into how the acting far-field stresses, applied wellbore pressures, crack length, and orientation angle influence the crack growth morphologies including planar fractures, curved and cyclic fractures. The study is important not only for a proper selection of the cement slurry but also for the definition of allowable pressures during the wellbore lifespan. Inappropriately selected parameters might lead to the loss of wellbore integrity to a point as early as the start of a well’s life.

Bending rigidity exponent of a two-dimensional crystalline membrane with arbitrary number of flexural phonon modes.

We investigate the elastic behavior of two-dimensional crystalline membrane embedded into real space taking into account the presence an arbitrary number of flexural phonon modes d_{c} (the number of out-of-plane deformation field components). The bending rigidity exponent η is extracted by numerical simulation via Fourier Monte Carlo technique of the system behavior in the universal regime. This universal quantity governs the correlation function of out-of-plane deformations at long wavelengths and defines the behavior of renormalized bending rigidity at small momentum ϰ∼1/q^{η}. The resulting numerical estimates of the exponent for various d_{c} are compared with the numbers obtained from the approximate analytical techniques.

The structural-mechanical damage behavior of rice bran layer under tensile processing for moderate milling

Bran layer moderate removal during rice milling is a crucial process for reducing rice broken rate and nutrient loss. The bran layer structural-cracking behavior is analyzed using a self-developed in-situ observation tensile tester with high-speed image acquisition. The rice bran tissue microstructure, chemical composition, cracking morphology are in-depth investigated. The results show that rice bran pericarp cells are of reticulate network, cell shape with rectangular or elliptical.significant differences in cell distribution and density across rice varieties, with Japonica rice (NJ5055) with a denser and more uniform structure, exhibiting higher ductility and tensile strength. The rice bran exhibited linear elastic rheological behavior. The bran tensile property is different under tensing directions, the tensile strength shows longitudinal (Y) > radial (X). Cracking along the cell long axis is Y direction, showing orderly line cracking path. Cracking along cell short axis is X direction, showing zigzag cracking path. Pericarp cells geometrical structure determines the mechanical strength and cracking-removal resistance ability of rice bran. The pericarp layer significantly enhances the ductility of the bran layer, allowing it to stretch and deform under stress, thereby improving overall mechanical performance. Rice bran structural-mechanical properties are affected by micro-structure and components.

Mechanical properties of teguline clay pellet mixtures during continuous oedometric compression

Clay pellet mixtures are generally compressed to improve their engineering performance. Deepening the comprehension of the mechanical properties of these mixtures in the complete compression process facilitates the benefit to the engineering design and their utilization. In this study, the effects of soil grain size distribution, water content and dry density on the mechanical properties and microstructure of Teguline clay pellet mixtures during a continuous oedometric compression process are explored. Three types of soil pellet mixtures, including mixture A (grain size ≤5 mm), mixture B (≤ 0.4 mm) and mixture C (2–5 mm), were prepared with different water contents of 7%, 8% and 12% respectively. Subsequently, continuous oedometeric compression was undertaken to explore their mechanical behaviours of the soil pellet mixtures. After that, the microstropic structures of the compacted pellet mixtures were investigated using mercury intrusion porosimetry (MIP). The results indicated that mixture A has a minimal initial packing density of pellet mixtures, while mixture C has a maximum one at the initial compression stage. After completion of compression, the compression curves of the pellet mixtures tended to converge uniformity at a semilogarithm coordinate as the vertical stress increased. All of the compression curves presented a concave shape at the plastic compression stage, which is significantly influenced by grain size distribution and water content. In contrast, the elastic compression and rebound behaviours are little affected by the grain size distribution and water content. As far as the microstructure is concerned, compacted samples prepared by mixture A or C presented a unimodal pore structure, while those by mixture B showcased a bimodal pore structure. In comparison with the unimodal pore distribution of the undisturbed stiff clay, the compacted samples displayed a pseudo-unimodal pore distribution because the inter-aggregate pores still existed. A double tangent method was proposed to determine the delimiting pore diameter of the pseudo-unimodal pore distribution curves and found that the delimiting pore diameter decreased with the increase of dry density and water content. Moreover, the inflexion point for the pore diameter of compacted samples prepared by coarse soil was larger than that of fine soil. Combining this work with previous research, it was found that the high compression of coarse soil easily causes the pseudo-unimodal shape, which is also impacted by water content and particle properties. This work could help deepen the understanding of the mechanical characteristics and microstructure of the stiff clay pellet mixtures during continuous oedometric compression.

Mesogen Organizations in Nematic Liquid Crystal Elastomers Under Different Deformation Conditions.

Liquid crystal elastomers (LCEs) exhibit unique mechanical properties of soft elasticity and reversible shape-changing behaviors, and so serve as potentially transformative materials for various protective and actuation applications. This study contributes to filling a critical knowledge gap in the field by investigating the microscale mesogen organization of nematic LCEs with diverse macroscopic deformation. A polarized Fourier transform infrared light spectroscopy (FTIR) tester is utilized to examine the mesogen organizations, including both the nematic director and mesogen order parameter. Three types of material deformation are analyzed: uniaxial tension, simple shear, and bi-axial tension, which are all commonly encountered in practical designs of LCEs. By integrating customized loading fixtures into the FTIR tester, mesogen organizations are examined across varying magnitudes of strain levels for each deformation mode. Their relationships with macroscopic stress responses are revealed and compared with predictions from existing theories. Furthermore, this study reveals unique features of mesogen organizations that have not been previously reported, such as simultaneous evolutions of the mesogen order parameter and nematic director in simple shear and bi-axial loading conditions. Overall, the findings presented in this study offer significant new insights for future rational designs, modeling, and applications of LCE materials.

A photo-chemo-mechanical coupling constitutive model for photopolymerization-based 3D printing hydrogels

Photopolymerization-based 3D printing has emerged as a key technology in hydrogel manufacturing, broadening the attributes of hydrogels and extending their applications into diverse engineering fields. However, the mechanical properties of hydrogels dramatically impact the functionality and quality in practice. It is necessary to develop an appropriate theoretical model to predict the evolution of the mechanical properties of hydrogels during the photopolymerization process. In this work, systematical experiments were performed to investigate mechanical properties of PAAm hydrogel under different photopolymerization condition. The results reveal a noticeable increasement in both elastic and viscous behavior of hydrogel with the advancement of polymerization. To fully capture the experimental observations, we developed a coupled photo-chemo-mechanical theoretical framework that integrates reaction kinetics with a physically-based viscoelastic constitutive model. Within this model, the degree of conversion serves as an internal variable, which related to microscopic structures such as correlation length, and tube diameter. The developed model exhibits remarkable prediction ability for hydrogels with various degree of polymerization. The current work paves a potentially new avenue for understanding the evolution of mechanical properties in photopolymerized hydrogels, providing theoretical guidance for the manufacturing of hydrogels through photopolymerization-based 3D printing.

3D-printed MOF/MoS2 aerogel for dye adsorption and photocatalytic degradation

The escalating challenge of water resources contamination, attributed to toxic pollutants, requires urgent attention from both governments and society. Furthermore, the inefficacy of conventional water treatment methods emphasizes the critical necessity for exploring the development of affordable, renewable, and high-performance materials, which should, for instance, enable the mutual adsorption and photocatalytic degradation of organic pollutants. Here we employed the 3D printing technique to manufacture an aerogel based on alginate, gelatin, and carboxymethylcellulose incorporated with 5 and 7.5 wt % of MOF/MoS2. FTIR spectra and EDS analysis evidenced the presence of MOF/MoS2 in the structure of the aerogels, while Helium pycnometer analysis and SEM micrographs demonstrated that the aerogels presented low density and a porous structure with porosity above 80 %. The swelling test showed that the aerogels displayed a high water absorption capacity (1400 %) after 70 h of immersion. The rheology test demonstrated that elastic behavior prevails over viscous behavior (G' > G″) and the incorporation of 7.5 wt % MOF/MoS2 favored shear thinning and viscosity recovery in the hydrogel. Adsorption tests to methylene blue (employed as a model) showed that the aerogel (HD) without the presence of MOF/MoS2 and the aerogels HD/MOF/MoS2 5 % and MOF/MoS2 7.5 % showed removal efficiencies of 16.77 %, 28.66 %, and 95.86 %, respectively. Conversely, the photodegradation test showed that HD/MOF/MoS2 5 % and HD/MOF/MoS2 7.5 % had an efficiency of 89 % and HD of 80 %. Therefore, our results demonstrate that the developed aerogels are promising candidates for the adsorption and photodegradation of dye while being low-cost, environmentally friendly, and easy to manufacture.

A Theoretical Study on Static Gas Pressure Measurement via Circular Non-Touch Mode Capacitive Pressure Sensor.

A circular non-touch mode capacitive pressure sensor can operate in both transverse and normal uniform loading modes, but the elastic behavior of its movable electrode plate is different under the two different loading modes, making its input-output analytical relationships between pressure and capacitance different. This suggests that when such a sensor operates, respectively, in transverse and normal uniform loading modes, the theory of its numerical design and calibration is different, in other words, the theory for the transverse uniform loading mode (available in the literature) cannot be used as the theory for the normal uniform loading mode (not yet available in the literature). In this paper, a circular non-touch mode capacitive pressure sensor operating in normal uniform loading mode is considered. The elastic behavior of the movable electrode plate of the sensor under normal uniform loading is analytically solved with the improved governing equations, and the improved analytical solution obtained can be used to mathematically describe the movable electrode plate with larger elastic deflections, in comparison with the existing two analytical solutions in the literature. This provides a larger technical space for developing the circular non-touch mode capacitive pressure sensors used for measuring the static gas pressure (belonging to normal uniform loading).

Rheological behavior and microscopic characteristic of electromagnetic thermal activated crumb rubber and SBS modified asphalt

Rubber activation provides a feasible approach for the preparation of high-content rubber modified asphalt without increasing the complexity of the production process. The electromagnetic thermal activation method was used for crumb rubber. The high dosage (30 % mass ratio of neat asphalt) activated crumb rubber and SBS (1.2 % mass ratio of neat asphalt) modified asphalt (ARMA) was prepared. The neat asphalt (NA) and 20 % non-activated crumb rubber modified asphalt (RMA) constituted the control group. Storage stability, rheological behavior, and microscopic properties tests were conducted to evaluate the performance differences of them. The rheological behavior of RMA and ARMA was superior to NA. The electromagnetic thermal activation method fragmented rubber particles into numerous disordered small particles, thereby expanded the contact area with asphalt. This resulted in the storage stability of ARMA significantly better than that of RMA. The cross-linked wrinkles were generated by the combined effect of SBS modifier and activated crumb rubber, which enhanced the rheological, anti-fatigue, and elastic behavior. Both RMA and ARMA exhibited high-temperature PG grades of 82˚C. At 70°C, ARMA retained the capability to endure Extremely Heavy Traffic Grade conditions. At a strain level of 2.5 %, ARMA exhibited a 178 % increase in fatigue life compared to RMA. The crumb rubber was dispersed within the RMA and ARMA. Both ARMA and RMA did not exhibit the obviously bee-structure. However, ARMA exhibited a stronger polymer network. Moreover, both the carbonyl index and sulfoxide index of ARMA were lower than those of RMA and NA. The activation process improved the compatibility between rubber and asphalt, and realized the high value utilization of waste rubber.

Shear resistance design of prefabricated corrugated steel plate shear walls with reinforced boundary elements

This paper investigates the buckling behavior and shear-bearing capacity of prefabricated corrugated steel plate shear walls (PCSPSWs) with reinforced vertical boundary elements (VBEs). The PCSPSWs are solely connected to the frame beams, and therefore, they can be positioned flexibly within the frame. However, there is currently no available shear-bearing capacity design method for such PCSPSWs. Firstly, this paper conducts a numerical investigation into the elastic buckling behaviors of PCSPSWs using finite element analysis (FEA). The prediction formulas for elastic buckling loads are fitted considering the influence of VBEs’ stiffness on the corrugated steel plates (CSPs). Then, the elastic-plastic buckling performance of PCSPSWs is analyzed numerically. The stability factor (φ) is proposed to predict the shear-bearing capacity of PCSPSWs by introducing the normalized slenderness ratio (λn). Subsequently, this paper explores the effects of PCSPSWs’ position within the frame and the influence of linear stiffness ratios between the frame beams and columns on the shear-bearing capacity of PCSPSWs through numerical analysis. Finally, the lower stiffness values of VBEs are discussed to provide some guidance for structural designers.

Hyperinelasticity. Part II: A stretch-based formulation

A generalisation of the hyperinelasticity modelling framework devised in Part I of this sequel is formulated here, by presenting a (principal) stretches-based hyperinelastic deformation energy function WF. This generalisation is based on the premise that the (principal) stretches λj may assume any arbitrary real-valued exponents, rather than being restricted to the prescriptive powers 2 and −2, as in principal invariants-based models. The motivation behind this extension is to reduce the overall number of model parameters and thereby increase the versatility of the application of the hyperinelasticity framework, as well as to provide a more universal model. The ensuing hyperinelastic model is then applied to a wide range of extant experimental datasets encompassing foams, glassy and semi-crystalline polymers, hydrogels and liquid crystal elastomers, over both elastic and inelastic deformation ranges including yield, softening and plateau, and hardening behaviours, under tensile and compressive deformations. Upon demonstrating the favourable simulation of the foregoing behaviours by the model, its application is then extended to account for other nuanced aspects of inelasticity such as the effects of rate of deformation, crystallinity volume and angle of printing in 3D printed lattice structures. This augmentation is done via devising a generalised modelling framework which allows for the incorporation of a generic tensorial (including rank zero scalar) field of inelasticity-inducing factors into the core model, resulting in the model parameters to evolve with an appropriate measure of the factor of interest; e.g., deformation rate, crystallinity volume ratio etc. The proposed modelling framework will be shown to capture these effects proficiently. Given the simplicity of this modelling approach, as essentially an extension in the application of hyperelasticity, its versatility of implementation, and the favourable capturing of both elastic and inelastic behaviours, the devised hyperinelasticity framework is presented for application to the large elastic and inelastic deformation of polymers and elastomers.

An analytic solution for bending of multilayered structures with interlayer-slip

Layered structures are prevalent in both natural environments and engineered composite materials. The elastic bending behavior of these structures is primarily governed by properties of their abundant interfaces. While the behavior of two- and three-layered beams has been extensively studied, this research shifts the focus to the impact of elastic shearing at interfaces on the deflection of multilayered structures comprising a substantial number of layers. We present an analytical solution indicating that the bending properties of multilayered beams and plates are nonlinearly dependent on interfacial stiffness. Denoting Se as the effective bending stiffness of an n-layered beam of length L, and S0 as the bending stiffness of a perfectly bound counterpart, we arrive at SeS0=11+(n2−1)tanhαLαL where αL represents a dimensionless parameter related to geometry and material properties. The analytical solutions, validated through finite element simulations, highlight the substantial variations in stiffness across different layered structures. This solution could also be instrumental in assessing interfacial damage and delamination in lamellar composites.

Optimal fare and headway for a demand adaptive paired-line hybrid transit system in a rectangular area with elastic demand

Demand adaptive paired-line hybrid transit systems that integrate fixed- and flex-route transit have emerged in the last decade and attracted increasing attention because of their potential to improve accessibility for passengers. To facilitate the operation of such a hybrid transit system, this study develops a model to determine the optimal fare and headways associated with fixed- and flex-route transit along a rectangular corridor. Compared with existing literature, the novelty of this study lies in designing the fare structure while simultaneously considering demand elasticity and passenger behaviour. A continuous approximation modelling approach is employed to derive the agency’s and travellers’ cost components. Using these, a nonlinear programming optimisation model is formulated to minimise the total user cost subject to the agency’s nonnegative revenue constraints and passengers’ route choice behaviour, which is characterised as a path-size logit model. Numerical experiments are performed using a stylised network to examine the properties of the model, in which the solution is obtained by combining a brute force method that enumerates headway and fare combinations and an iterative method that determines equilibrated passenger choices. The results show that as potential demand density increases, fare and headway fluctuate and drop, while the percentage of passengers choosing to ride on flex-route transit increases. In addition, there may be an optimal maximum offset distance, which is defined as the width of the corridor to be covered by the transit system, when the potential demand density is low, leading to minimum user cost and maximum travel demand within the service area.

Seismic performance and design of an innovative structure with controlled rocking shear wall using ring springs

The application of ring springs in civil engineering, aimed at improving the seismic behavior of structures, has been largely overlooked despite their many advantages. These springs are highly durable, heat-resistant, low-maintenance, and self-centering, meaning that they withstand large deformations while always returning to their original state. Structures equipped with properly designed ring springs survive earthquakes without suffering major damage or plastic deformation, making them an excellent investment in terms of both economic efficiency and sustainable resource use. This paper explores a new use for ring springs in earthquake-resistant structures, with a focus on their implementation into controlled rocking shear walls. A parametric study utilizing the Non-Linear Time History Analysis method was conducted on a simplified model to investigate the rocking behavior and derive a design methodology based on the obtained results. A comparative study was conducted on elastic, non-linear, and rocking shear walls to demonstrate the feasibility and design principles of the rocking systems. Furthermore, the results of the comparative studies provided evidence supporting the efficacy of incorporating ring spring dampers into the rocking systems. The controlled rocking shear wall demonstrated elastic behavior during seismic loading, indicating that the addition of ring spring dampers was effective in enhancing its performance. On the other hand, the conventionally designed numerical model exhibited nonlinear behavior at its base. The developed design procedure ultimately enables the practical application of controlled rocking shear walls using ring spring dampers in earthquake engineering.

(Non)linear Interfacial Rheology of Tween, Brij and Span Stabilized Oil-Water Interfaces: Impact of the Molecular Structure of the Surfactant on the Interfacial Layer Stability.

During emulsification and further processing (e.g., pasteurizing), the oil-water interface is mechanically and thermally stressed, which can lead to oil droplet aggregation and coalescence, depending on the interfacial properties. Currently, there is a lack of insights into the impact of the molecular structure (headgroup and FA chain) of low molecular weight emulsifiers (LME) on the resulting interfacial properties. Additionally, the crystallization/melting of the oil/the emulsifier is often neglected within interfacial rheological experiments. Within this study, the stability of interfaces formed by Tween, Span or Brij was determined as a function of their molecular structure, taking crystallization effects of the LME into account. The headgroup was kept constant while varying the FA, or vice versa. The interfacial film properties (viscoelasticity) were investigated at different temperatures using dilatational and interfacial shear rheology. Both the headgroup and the FA chain impacted the interfacial properties. For the same FA composition, a rather small hydrophobic headgroup resulted in a higher packed interface. The interfacial elasticity increased with increased FA chain length (C12 to C18). This seemed to be particularly the case when the emulsifier crystallized on the interface among cooling. In the case of a densely packed interface, network formation due to chain crystallization of the LME's FA chains occurs during the cooling step. The resulting interface shows predominantly elastic behavior.

An Experimental Investigation on the Effects of Temperature and Confining Pressure on the Static and Dynamic Behaviors of Shale Rocks

Abstract To better understand the associated thermal and mechanical effects on the elastic behaviors of shale rocks, we examine the shale rocks at reservoir stress (static) and elastic conditions (dynamic) at varying temperature (25–110°C) and pressure (5–55 MPa) conditions through coupling dynamic–static experimental measurements. The results illustrate that the shale’s P- and S-wave velocities increase with the increasing confining pressure but decrease with the elevated temperature. For the pressure history, ultrasonic P-wave velocities upon hydrostatic unloading are slightly larger than the loading ones, whereas S-wave velocities are almost overlapping together. Meanwhile, the temperature elevation causes much less velocity reduction at a higher confining pressure than lower confining pressure. The measured data demonstrate that the static bulk modulus is more sensitive to the confining pressure than the dynamic bulk modulus. Moreover, with the elevated temperature, the dynamic bulk moduli separate by showing a decreasing trend in either hydrostatic loading or unloading. The loading–unloading cycle shows that the static bulk moduli present values approaching the dynamic ones at all temperature levels when the confining pressure is initially unloaded from the maximum pressure. Both static and dynamic bulk moduli decrease with the continued unloading, with more decrement for the static bulk modulus. The coupling effects of the pressure and temperature on the static and elastic properties of shale samples imply that, in the practical shale reservoir characterization process, temperature and pressure influences should be considered to characterize the relation of dynamic and static properties of shale rocks. The laboratory investigations on shales imply that the relation of dynamic and static properties is pressure dependent mainly due to the intrinsic behavior of fracture, soft pore, and microstructure in the rock frame.

Performance of laser metal deposition on hot-rolled stainless steel for hybrid steel structures

The construction sector is increasingly recognising the potential of metal additive manufacturing (AM) for fabricating complex steel details with enhanced performance and reduced resource usage. In the coming years, the application of AM technologies is expected to advance, leading to the development of new structural elements and improved performance of existing ones. This progression involves the integration of conventional construction steel with AM techniques, such as laser metal deposition (LMD), to create hybrid systems that incorporate efficient details. LMD offers the advantage of overcoming size limitations associated with laser powder bed fusion (LPBF) while leveraging its geometric capabilities. In this study, the mechanical behavior of hybrid steel components, fabricated using LMD on AISI316L stainless steel plates, was investigated through an extensive experimental campaign involving 40 samples. Axial tests, fatigue tests, and material characterisation were conducted to evaluate strength criteria and long-term behavior. Results demonstrate that LMD-produced AISI316L exhibits mechanical properties compliant with EN1993's "Design of steel structures" encompassing elastic and plastic behavior. Furthermore, both LMD samples and hybrid specimens exhibit promising fatigue performance, aligning with the highest fatigue detail category (detail category 160) for conventional steel details.

Synthesis and characterization of additively manufactured microcapsule‐reinforced polylactic acid composites for autonomous self‐healing

AbstractMaterial extrusion‐based additive manufacturing (AM) process builds the objects/structures through a precise feedstock deposition in a layer‐by‐layer manner. Polylactic acid (PLA) is a popular biodegradable feedstock in AM, while octyl methoxycinnamate (OMC) is known for its eco‐friendliness and ultraviolet (UV) protection properties. The present study focuses on the novel infusion methodology of OMC‐based microcapsules into PLA to develop self‐healing composite filaments. Post‐composition iterations, the optimum compositions for the filler and plasticizer were determined, and the filaments were extruded. Microcapsule‐infused PLA and the neat PLA samples were printed as per the American Society for Testing and Materials (ASTM) standard. The uniaxial tensile test results showed that the failure strain endured by the microcapsule‐infused samples was about 10 times more than the neat PLA counterparts. It is attributed to the effective load distribution and the complex polymerization reaction (due to the interaction of OMC with the matrix). Fracture surface morphology of the samples via optical microscopy (OM) and field emission scanning electron microscope (FESEM) affirmed the strong PLA‐OMC interface. A depreciation in the Brinell Hardness for the microcapsule‐based samples was due to the localized indenter force, causing greater damage in a narrow area than microcapsule ruptures' healing ability.Highlights The optimized composition of PLA: plasticizer:microcapsule is 1:0.04:0.05. Microcapsule‐infused PLA has improved Young's modulus and failure strain. Interaction with microcapsules improves elastic behavior and self‐healing. FESEM reveals close bonding of microcapsule with the PLA matrix.

Effective elastic behavior analysis of three-layer quasicrystal composite plates

In this paper, the effective elastic behavior of three-layer quasicrystal composite plates are forecasted. Firstly, effective properties of the first and third layers quasicrystal composite plates containing ellipsoidal inclusions are obtained according to the Mori-Tanaka model. Secondly, the three-layer composite plates effective behavior parameters are computed by employing the general matrix approach. The numerical examples reveal the influence of the inclusions geometry and volume fraction on the three-layer quasicrystal composite plates effective behavior parameters. The findings indicate that changing the elastic constants of the phason field and phonon-phason coupling field of inclusions will affect the effective behavior parameters of the three-layer quasicrystal composite plates. The increase in layers to some extent reduces the effective behavioral parameters.

Electronic structures, thermal properties and molecular dynamics of CsGdCl3 and CsNdCl3 perovskite crystals by first-principles calculations

Lanthanide-based perovskite crystals have been characterized for proposing material design guidelines of perovskite solar cell with stability of photovoltaic performance. The purpose of this study is to characterize band structures, phonon dispersions, molecular dynamics, electronic and thermal conductivities of CsGdCl3 and CsNdCl3 perovskite crystals by first-principles calculation analysis. The CsGdCl3 and CsNdCl3 crystals had wide distributions of 5d orbital of Gd3+ ion, 5d and 4f orbitals of Nd2+ ion near conduction band state as n-type semiconductive behavior. The phonon dispersions and thermal conductivities indicate effects of acoustic phonon on carrier scattering. The CsGdCl3 crystal suppressed carrier scattering as elastic behavior, improving electron diffusion and dynamic stability. The CsNdCl3 crystals expected to cause carrier scattering with acoustic phonon and molecular dynamics. The CsGdCl3 crystal have the superior potential of the performance as semiconductor characteristics equivalent to the performance of the CsPbCl3 crystal.