Fracture failure is an essential concern on the design, manufacture and utilization of piezoelectric functional materials. Both traditional piezoelectric ceramics and new flexible piezoelectric materials demand objective modeling of fracture under the coupled action of electric and mechanical fields. Currently, the widely developed electromechanical fracture phase-field model (EM-PFM), which employs the mechanical energy release rate as the crack driving force, cannot sensibly predict some of the classical experimental reports. In this work, the necessity of the mechanical energy release rate as the fracture criterion is revised based on a semi-analytical demonstration on the EM-PFM, and a new crack driving force formulation is proposed. More specifically, the new crack driving force consists of the mechanical energy release rate contributed from the effective stress and a part of the electro-mechanical coupled energy release rate, where the transformation rate of the latter is controlled by an intrinsic material parameter. The proposed EM-PFM is numerically implemented in a multi-field finite element framework in the commercial software ABAQUS via a user element subroutine. A representative one-dimensional ideal numerical test demonstrates the rationality of the present model. Most importantly, for the first time, we achieved numerical reproduction of Park and Sun’s classical experiments in the EM-PFM without changing any piezoelectric coefficients. The present work contributes to a better understanding of piezoelectric materials and is beneficial in predicting the fracture of piezoelectric materials realistically.

Rapid and accurate state assessment of retired batteries (RBs) is a prerequisite for the economic viability and safety of their second-life utilization. However, this task is fundamentally hindered by the absence of historical data, heterogeneous states, and diverse battery types. To overcome these barriers, this study proposes a robust framework integrating fast direct current (DC) pulse testing with deep transfer learning for joint estimation of state of charge (SOC) and health (SOH). The framework employs a sequential strategy where the estimated SOC profiles are utilized as key inputs for SOH estimation. The transfer learning pipeline encompasses source-domain pre-training, cross-domain feature matching, and target-domain fine-tuning. During feature matching, an adversarial network with distribution constraints extracts domain-invariant features. The framework's efficacy and generalizability are validated across two independent datasets, encompassing two fast DC multi-step pulse testing protocols (≤ 200 s) and five battery types across three chemistries. The base model yields superior accuracy, with SOC mean absolute errors (MAEs) within 1.45%, and SOH MAEs within 1.55%. Notably, without requiring any historical usage data or target-domain fine-tuning, the pre-trained model directly generalizes to identical battery types under completely unseen operating conditions, maintaining SOC MAEs within 1.95% and SOH MAEs within 1.79%. Furthermore, when transferring across different chemistries with only 10% labeled data, it sustains SOC MAEs within 2.67% and SOH MAEs within 1.47%. Beyond algorithmic accuracy, this approach reduces testing time and energy consumption to only 7.88% and 15.04% of conventional full-capacity calibration, providing a highly practical and cost-effective tool for large-scale battery recycling.

Extracted natural gas hydrate is a multi-phase and multi-component mixture, and its complex composition poses significant challenges for transmission and transportation, including phase changes following extraction and sediment deposition within the pipeline. This study examines the flow and heat transfer characteristics of hydrates in a riser, focusing on the multi-phase flow behavior of natural gas hydrate in the development riser. Additionally, the effects of hydrate flow and seawater temperature on heat exchange are analyzed by simulating the ambient temperature conditions of the South China Sea. The findings reveal that the increase in unit pressure drop is primarily attributed to higher flow velocities, which result in increased friction of the hydrate flow within the development riser. For example, at a hydrate volume fraction of 10%, the unit pressure drop rises by 166.65% and 270.81% when the average inlet velocity is increased from 1.0 to 3.0 m/s (a two-fold increase) and 5.0 m/s (a four-fold increase), respectively. Furthermore, the riser outlet temperature rises with increasing hydrate flow rates. Under specific heat loss conditions, the flow rate must exceed a minimum threshold to ensure safe transportation. The study also indicates that the riser outlet temperature increases with higher seawater temperatures. Within the seawater temperature range of 5°C to 15°C, the heat transfer efficiency is reduced compared to the range of 15°C to 20°C. This discrepancy is due to the fact that as the seawater temperature rises, the convective heat transfer coefficient between the hydrate and the inner wall of the riser also increases, leading to improved overall heat transfer between the hydrate and the pipeline.

Understanding the inhomogeneity of the battery module is crucial for optimizing its performance and ensuring the safe operation of the energy storage system (ESS). This paper examines how various factors that can cause inconsistencies affect the modules' performance under two scenarios for ESS and conducts a comprehensive module performance evaluation. Initially, the influences of topology structure, connector resistance, temperature, and manufacturing tolerances are investigated. Different topologies exhibit distinct differences in various aspects of the module performance, especially State of Charge (SOC) consistency and temperature consistency. Among the remaining factors, connector resistance has the greatest impact on SOC consistency, while manufacturing tolerance exerts significant influence on discharge consistency and state of health consistency. The substantial impact of application scenarios on module temperature performance underscores the critical importance of considering both scenarios and topological configurations when designing thermal management systems. Subsequently, a comprehensive evaluation method is proposed, considering the distribution uncertainty of internal parameters and seven performance evaluation indicators. Using orthogonal experiments, the comprehensive performance score (CPS) of the four modules in scenario 1 is compared, considering the effect of operating conditions, design parameters, initial state, and manufacturing tolerance which indicates Cross-end has the highest CPS, 13.31 % higher than that of Ladder-up. Furthermore, in Scenario 2, a reasonable parallel connector resistance can enhance the CPS of the Cross-end module by 74.9 %. This research provides valuable insights into battery module inconsistency, which can significantly contribute to performance enhancement, thermal safety, and the optimization of design.

Fiber-matrix interfaces play a critical role in determining the durability of composite structures. The prospect of developing self-healing interfaces could pave the way for significantly extending their service life. In this study, we investigate the self-healing potential of nanostructured layers at interfaces of epoxy/carbon fiber composites. A three-dimensional thermomechanical model of epoxy/carbon fiber composites with a self-healing nanostructured polycaprolactone (PCL) layer at fiber-matrix interfaces is developed. A fully coupled thermal-stress procedure is established to simulate the healing process of interfaces. To better capture the realistic interfacial properties of this material, both residual stress and surface roughness are considered. Temperature-dependent material properties are included in the model, and heat generation during PCL recrystallization is analyzed. The proposed model is validated by comparing numerical predictions with the microbond testing data of this novel composite material. Numerical results reveal that surface roughness enhances interfacial strength while residual stresses reduce it. Furthermore, the healing process not only restores the interface bonds but also reduces thermal residual stress in the healed material. This study provides valuable insights into leveraging self-healing interfaces to enhance the durability of composite structures.

NbMoSiN composite and gradient films were deposited by magnetron sputtering with nitrogen flow design, and their structural, electrochemical and tribological behaviors in simulated body fluids were investigated. The results revealed that the NbMoSiN composite film composed beta-Nb2N, MoSi2 nanocrystals, Si3N4, and amorphous phases, while the NbMoSiN gradient film was completely amorphous. The film with 30 sccm nitrogen flow demonstrated enhanced corrosion resistance, attributed to the increased MoSi2 and Si3N4. The gradient film exhibited poor passivation ability and compositional inhomogeneity, leading to accelerated corrosion. The film's wear rate at 10 sccm nitrogen flow was significantly lower due to the hard nitride phase and multiphase interface strengthening. Higher nitrogen flow increased the silicide phase and reduced the friction coefficient through hydration.

To mitigate the risks of overheating and thermal runaway in lithium-ion batteries, this study proposes a novel sandwich-type fire-resistant flexible composite phase change material (CPCM), referred to as PEE@EBF. The core material (PEE) was created by melt-blending paraffin wax (PW), expanded graphite (EG), and ethylene-vinyl acetate copolymer (EVA). The outer layer, a fire-resistant coating (EBF), was applied to the surface of PEE and consists of epoxy resin (EP), boron nitride (BN), and the composite flame retardant (CFR). Test results demonstrated that PEE@EBF maintained structural integrity, exhibiting no significant deformation or leakage after being heated at 80 degrees C for 5 h. PEE@EBF also displayed a high latent heat of 166.6 J/g, thermal conductivity of 0.8 W/(m.K), and excellent electrical insulation properties. Furthermore, it achieved a UL94 V-0 flame retardant rating, with notable reductions in peak heat release rate (PHRR) and peak smoke production rate (PSPR) by 67.8 % and 81.8 %, respectively. During long-term cycling at 4C, the peak temperature (PT) and maximum temperature difference (MTD) of batteries in the module incorporating PEE@EBF were reduced by 11.8 degrees C and 4 degrees C, respectively, compared to natural convection cooling. In addition, the heat generated during the battery thermal runaway was efficiently absorbed and transferred by PEE@EBF, delaying the irreversible thermal runaway process by 633 s. This indicated that the sandwich-type PEE@EBF was suitable for thermal management and fire protection in lithium-ion batteries or energy storage devices.

Organic phase change materials (PCMs) are commonly used for battery thermal management. Organic petroleum-based PCMs such as paraffin have an adverse effect on environment. Fatty acids as environmentally friendly bio-based PCMs, have enormous potential in sustainable development strategies. Nevertheless, the application of fatty acids in battery thermal management (BTMS) is restricted by the leakage of liquid PCM, poor thermal performance and the improper phase change temperature. We proposed a novel bio-based eutectic composite phase change materials (CPCM) with enhanced thermal conductivity and excellent shape-stabilization, composed of ethylene-vinyl acetate (EVA), Aluminum nitride (AlN), and the eutectic PCM of Lauric acid (LA) and Stearic acid (SA). Significantly, the screened eutectic PCM of LA-SA possesses a suitable phase change temperature(37.03 degrees C) corresponding to the battery operating temperature, and long-term thermal cycling stability of up to 100 cycles. And the cross-linked structure of EVA effectively encapsulated the eutectic PCM, whose mass only lost below 4% after being heated at 80 degrees C for 24 h. Simultaneously, the introduction of AlN can greatly improve their heat transfer ability and mechanical properties. LA-SA/EVA/AlN composites with 5 wt% AlN has adequate latent heat of 107.94 J.g(-1) and high thermal conductivity of 0.726 W.(mK)(-1) as well as with low flexural strength of 1.72 MPa. Additionally, the proposed CPCM with 5 wt% AlN achieved the maximum temperature of battery below 45 degrees C during 4C discharging test. It suggested that the CPCM incorporated with AlN is capable effective cooling battery and dissipate energy inside PCM rapidly.

The battery thermal management system (BTMS) is critical to electric vehicle (EV) safety and performance. In this paper, a novel cooling plate integrated with liquid microchannels and phase change material (PCM) is developed for use in BTMS, and its thermal performance at a high discharge rate of 5C is investigated. To improve temperature inhomogeneity, the non-metallic inlet shell is used to transport the coolant to the axial microchannels, which significantly reduces the temperature difference by 3.8 degrees C. Additionally, compared with I-shaped microchannels, the design of S-shaped microchannels increases the flow area for coolant and promotes the cooling effect, controlling the maximum temperature at 34.53 degrees C. Then, the parameters, including the number of microchannel layers, radial extension angle, inner diameter, and PCM thickness, are optimized by the multi-objective optimization, and its energy consumption is decreased to 9.61 x 10-6Wh and its energy density raised to 108.94 Wh center dot kg  1. Moreover, the cooling performance improves with the increase of the inlet velocity, and a balance between cooling performance and energy consumption is achieved when the inlet velocity is 0.06 m center dot s  1. Cross-convectional flow helps to enhance the temperature uniformity of the battery module further. The hybrid liquid cooling plate takes advantage of coupling active cooling and passive cooling; the energy consumption of BTMS is reduced by 46.3% without sacrificing the cooling capacity when delaying the beginning of active cooling after PCM passive cooling for 300 s. Furthermore, the PCM-embedded hybrid cooling plate slows the heat loss of batteries in cold environments, which can maintain their temperature above 20 degrees C after resting for 2 h at 0 degrees C. This work provides a reference for the hybrid cooling plate development of cylindrical batteries.

To enhance the cooling and preheating performance of the battery, a novel hybrid battery thermal management system (BTMS) containing bionic spiral fins wrapped with phase change material (PCM) and embedded liquid cooling is proposed. The cylindrical battery is strategically positioned on a spiral fin, the heat of the battery and PCM is transferred to the cold plate through the extended winglets. The thickness (L1), height (L2), distance (L3) and number of winding turns (N) of fin are optimized using the response surface method (RSM). The effects of the liquid cooling duration, flow rate, channel shape and direction of the flow channel on the latent heat recovery of PCM and the cooling performance of the battery module are analyzed. The results demonstrated that at the duration of 600 s and flow rate of 0.09 g/s, the liquid fraction of PCM reduced from 57 % to 26 %. Furthermore, the preheating efficiency of the BTMS was investigated under different parameter configuration and boundary conditions. The preheating temperature increased by 5.6 degrees C compared with the BTMS without fins. Additionally, the temperature difference (Delta T) of the BTMS with Layout 2 decreases by 0.5 degrees C compared with 4.1 degrees C of Layout 1 at flow rate of 0.5 g/s.

A hybrid BTMS considering heat dissipation and mechanical protection for prismatic battery modules is constructed, which combines the modularized liquid-cooling plate (MLCP) and the phase change material (PCM)negative Poisson's ratio structural laminboard. The effects of interior structure, flow direction, flow rate, and cooling strategy of the MLCP on the thermal performance of the battery module were investigated. It showed that the proposed MLCP was able to weaken the heating effect of coolant along the flow path by more than 50 % through modularized design. Furthermore, the alternating cooling strategy of sub-domains of MLCP was designed, which halved the energy consumption of liquid cooling systems. In comparison to the case without the laminboard, the maximum temperature and temperature difference of the case with it were reduced by 3.79 degrees C and 2.50 degrees C, respectively. Meanwhile, the maximum stress and total deformation of the battery cell were also decreased by 1.67 MPa and 78.1 mu m with the protection of the laminboard at 1000 N. With the MLCP and the multifunctional laminboard, the maximum temperature and temperature difference of the battery module were kept below 35 degrees C and 4 degrees C, respectively, even at a high discharge current of 100 A and under dynamic conditions.

In order to improve the cooling efficiency and temperature consistency of the air-cooled prismatic battery module, a novel multicomponent phase change material-spring plate (MPCM-SP) was developed in this work. The MPCM was formed by combining lauric acid (LA), polyethylene glycol (PEG), palmitic acid (PA), and carboxylated multi-walled carbon nanotubes (MWCNT-COOH). The melting temperature of MPCM can be adjusted within the range 37 degrees C to 65 degrees C, and the associated latent heat of phase change varied from 159 J center dot g(-1) to 209 J center dot g(-1). The optimized proportions of LA, PEG, PA, and MWCNT-COOH achieved through multiple-objective optimization were 65.55 %, 7.07 %, 25.38 %, and 2.00 %, respectively. The cooling performance of the MPCM-SP was examined by experimental verification and numerical evaluation. The inclusion of MPCM-SP in the air-cooling system resulted in a reduction of 3.41 degrees C, 3.74 degrees C, and 3.32 degrees C in the maximum temperatures of the U-shaped, Z-shaped, and I-shaped battery modules, respectively. Moreover, the temperature difference was decreased by 3.60 degrees C, 3.16 degrees C, and 2.42 degrees C, respectively. Additionally, in comparison to a single battery, a battery equipped with MPCM-SP had a 32.8 % reduction in thermal deformation in the thickness direction under a thermal expansion coefficient of 4.06 x 10(-6) K-1.

A novel battery thermal management system (BTMS) integrating phase change material (PCM) and liquid cooling is developed. Forked flow channels are designed to optimize coolant distribution and improve temperature uniformity of battery module. Subsequently, the effects of channel shape, entrance number and layers on thermal performance and power consumption are investigated. The results demonstrate that compared to hexagonal and triangular channel, the diamond channel results in power consumption reductions of 21 % and 11 %, respectively. The maximum temperature (T-max) and temperature difference (Delta T) of BTMS employing two channel entrances and four layers are 308.7 K and 2.9 K, respectively. As the flow rate increases from 0.1 g.s(-1) to 0.6 g.s(-1), the temperature rise of battery decreases by 3.9 K; when the coolant temperature rises 20 K, the corresponding pressure drop (Delta P) across the flow channel diminishes by 33 %. The optimal flow rate and the number of channel inlet are determined as 0.56 g.s(-1) and 2 respectively utilizing genetic algorithm. Additionally, the BTMS exhibits excellent heat dissipation performance under dynamic operating conditions.

A new framework based on the phase field method is developed to model the fatigue fracture behavior of fiber-reinforced composite laminates. The growth path of matrix cracks can be simulated more accurately compared to the classical model. Further, anisotropic fatigue accumulation effects are considered in this model. Comparisons between simulations by the phase field model with uniform fatigue accumulation effects and the proposed method are encouraging. The new framework proposed can more naturally capture different types of crack growth in fiber- reinforced composites. The reliability and potential of this framework to model fatigue behavior for fiber-reinforced composite laminates are demonstrated by investigating several numerical examples. Moreover, the finite element implementation utilizes a simpler and robust approach via the ABAQUS user-defined subroutine UMAT and UMATHT, including the so called AT1, AT2 and PF-CZM models and two solution strategies.

The easy leakage, low thermal conductivity and poor flexibility of phase change materials (PCMs) limit their application in battery thermal management systems (BTMS). To address these problems, a novel form-stable flexible composite phase change material (CPCM) with ethylene-vinyl acetate (EVA), expanded graphite (EG) and paraffin (PA) is designed and applied to battery module. EVA with a skeleton structure is employed as supporting material and EG is the thermal conductive filler. The effects of EVA content on the microstructure and cooling performances of CPCM are investigated under different cooling conditions. The temperature distribution of battery module and the liquid fraction of CPCM were visualized by numerical simulation. The results show the addition of EVA greatly improves the antileakage and shape stability properties of CPCM. When the content of EVA is higher than 30 wt%, the physical shape of CPCM remains nearly unchanged after 75 times of thermal cycling. The maximum temperature of battery module with CPCM is 49.2 degrees C at 4C discharge rate, which is reduced by 14.2 degrees C in comparison with that under natural convection. Furthermore, the maximum temperature difference of the battery module is kept within 5 degrees C during the 4C charge-discharge cycling tests.

A novel algorithm containing an adaptive cubature Kalman filter (ACKF) modified by Frobenius-norm-based (fro-norm-based) QR decomposition (QR) and H-infinity(H∞) filter based on electro-thermal model is proposed to estimate the state of charge (SOC) of lithium-ion batteries (LIBS). First, an electro-thermal model with a second-order RC equivalent circuit model (ECM) and a lumped thermal model is employed to identify the internal parameters of LIBS at different temperatures. Then, to solve the non-positive definiteness of the error covariance matrix, an adaptive cubature Kalman filter is modified by fro-norm-based QR decomposition (ACKF-QR). Finally, to cope with uncertain noises especially non-Gaussian noises, the H∞ filter is combined with ACKF-QR to estimate the battery SOC (ACKF-QR-H∞). The ACKF-QR-H∞ algorithm is validated under different working conditions at different temperatures with incorrect initial values. The SOC estimation MAXE (Maximum absolute error) of the ACKF-QR-H∞ algorithm is less than 1% and its SOC estimation MAE (Mean absolute error) and RMSE (Root mean square error) are less than 0.32%. As compared with the same algorithm without considering temperature variations, the SOC estimation error of ACKF-QR-H∞ algorithm can almost reduce by half in most cases. When various noises are added manually, the ACKF-QR-H∞ algorithm can remain robust.

In this work, an adaptive phase-field method is proposed for modeling fracture of hyperelastic materials at large deformations. The adaptive mesh refinement is facilitated by the variable-node elements, which are flexible to act as transition elements in the employed quadtree mesh. To control the adaptive process, we propose a combined phase-field and energetic mesh refinement criterion, where the energetic part exploits the strain energy threshold of the AT1 phase-field model which is used in this work. Both the compressible and incompressible neo-Hookean models are taken into account, and the latter is enforced by the plane stress condition to simplify the implementation. Several representative examples are studied to verify the accuracy and efficiency of the proposed adaptive phase-field method, in comparison to the available numerical and experimental reference data as well as the fixed locally pre-refined mesh. The simulated results show that the energetic part of the mesh refinement criterion can effectively prevent the delayed damage evolution when the phase-field initiates. Finally, the fracture process of a hyperelastic composite with inclusions is simulated to demonstrate the capacity of the proposed method for reproducing complex failure phenomena at large deformations.

This work presents an adaptive phase-field method incorporated into a finite element framework combined with variable-node elements to investigate the cohesive dynamic fracture. The proposed framework builds upon the regularized phase-field cohesive-zone model as its foundation utilizes a hybrid form of the history field to drive the crack evolution. A staggered iteration scheme is utilized to compute the displacement and phase-field variables for the coupled elastic-phase field system. The error indicator, utilizing the phase-field as well as the history strain variables, is employed to control the adaptive refinement process. The variable-node element technique facilitates adaptive mesh refinement, which is simple and flexible to act as a transition element between coarse and refined elements. In addition, an implicit HHT time integration scheme is employed for temporal discretization. Several standard problems are presented to showcase the efficiency and accuracy of the proposed method, highlighting its superiority when compared to the results documented in the literature. The results show that the proposed framework can significantly improve computational efficiency without affecting the accuracy of numerical results.

To improve the heat dissipation performance of the battery module, the fins are embedded in a hybrid battery thermal management system (BTMS) with phase change material (PCM) and air cooling. To balance cooling performance and energy consumption of BTMS, the variable-section fins inspired by the features of the beak and wing are proposed. Subsequently, the effects of the thickness of PCM, fin type, airflow velocity, and support frame width (L1) on cooling performance and power consumption of the battery module are investigated using the computational fluid dynamics (CFD) model at high rates of 3C charge and 4C discharge. The maximum temperature (T-max) of BTMS adding fin is significantly decreased by 3.4 degrees C at an inlet velocity of 3 m/s. Moreover, the power consumptions of BTMS with beak fin are reduced by 23% and 33% respectively compared with rectangle fin and wing fin. Additionally, the influences of structure parameters of bifurcated fin, such as angle (alpha), the length of end exposing air domain (L-2), and windward shape on cooling performance, temperature difference (Delta T), and power consumption are comprehensively analyzed. The results demonstrate that under the bifurcated fin alpha of 75 degrees and L-2 of 40 mm, the T-max, Delta T, and power consumption are 38.3 degrees C, 2.9 degrees C, and 2.6 x 10(-3)W respectively, a decrease of 0.4 degrees C, 0.4 degrees C, and 13% compared with BTMS with beak fin. Furthermore, the cooling performance of BTMS introducing delayed air cooling is researched, and the power consumption is observably reduced by 59%.