International Journal of Mechanical Sciences最新文献

{"title":"Industrial-scale manufactured acoustic metamaterials for multi-bandgap sound reduction","authors":"Xiaole Wang ,&nbsp;Ping Sun ,&nbsp;Xin Gu ,&nbsp;Siqi Xu ,&nbsp;Xudong Luo ,&nbsp;Zhenyu Huang","doi":"10.1016/j.ijmecsci.2025.110184","DOIUrl":"10.1016/j.ijmecsci.2025.110184","url":null,"abstract":"<div><div>Achieving mass manufacturability and convenient deployability is the cornerstone to enable the widespread adoption of acoustic metamaterials. This work is poised to address the current challenges associated with manufacturing and deploying acoustic metamaterials. The proposed acoustic metamaterials comprise the resonant and mounting parts assembled through stud-and-tube coupling. The resonant part consists of multiple unit cells connected by slender rods, and each unit cell contains four cantilever beam-type resonators with different geometric parameters for generating multiple bandgaps. The back side of the mounting part is flat and broad, facilitating the quick and secure attachment of the acoustic metamaterials on the surface of the host structure. The injection molding technique is employed to mass-produce the acoustic metamaterial specimens made of the Acrylonitrile Butadiene Styrene material. After that, the static mechanical characteristics of the acoustic metamaterial specimens are experimentally quantified by assessing the withstand tensile and compressive forces. Next, the underlying physics behind the dynamic mechanical characteristics of the acoustic metamaterial specimens are revealed by utilizing a combination of analytic, numerical, and experimental techniques. Finally, the acoustic metamaterial specimens deployed on a scaled-down aircraft cabin model are tested to verify the sound reduction effects in large-size and complex wave field environments. We find that the acoustic metamaterial specimens exhibit four complete locally-resonant bandgaps below 500 Hz, allowing multi-bandgap reduction of both air-borne and structure-borne noise. Our unique design of the multi-bandgap acoustic metamaterials and the practical prototypes manufactured at an industrial scale through injection molding represent a significant advancement toward the commercialization of acoustic metamaterials.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"293 ","pages":"Article 110184"},"PeriodicalIF":7.1,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coupled vibration model-driven intelligent fault diagnosis in canned motor pumps","authors":"Jintao Yao ,&nbsp;Taibo Yang ,&nbsp;Zhihao Bi ,&nbsp;Jiaxin Liu ,&nbsp;Qingbo He ,&nbsp;Zhike Peng","doi":"10.1016/j.ijmecsci.2025.110181","DOIUrl":"10.1016/j.ijmecsci.2025.110181","url":null,"abstract":"<div><div>Canned motor pumps have an unobservable internal structure, making it impossible to directly monitor their operational states or measure the transfer function from internal excitations to casing vibrations. This limitation poses significant challenges in accurately linking internal faults to measurable external signals. To address this issue, this study establishes a coupled vibration model of the canned motor pump to describe the transmission process from impeller hydraulic excitation to casing vibrations. Based on this model, four fault dynamic models are developed to simulate casing vibrations under different fault conditions, supporting fault mechanism analysis. Additionally, a model-based intelligent diagnostic framework is proposed, enabling accurate fault diagnosis under imbalanced data conditions. Experimental results show that the proposed method effectively captures fault characteristic frequency variations consistent with actual conditions. The spectrum of the simulated signals reflects clear physical significance, providing a robust basis for understanding fault mechanisms and improving the reliability and precision of fault diagnosis. This work offers a novel solution for linking internal fault dynamics to external measurements for canned motor pumps, providing a practical potential for handling imbalanced data and advancing fault diagnosis in complex enclosed mechanical systems.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"291 ","pages":"Article 110181"},"PeriodicalIF":7.1,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143738494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surface quality in ultrasonic-electrolytic internal grinding of GCr15 steel","authors":"Hongyin Zhang,&nbsp;Feng Jiao,&nbsp;Xiaoxu Lian,&nbsp;Yuehan Zhao,&nbsp;Ying Niu,&nbsp;Jinglin Tong","doi":"10.1016/j.ijmecsci.2025.110188","DOIUrl":"10.1016/j.ijmecsci.2025.110188","url":null,"abstract":"<div><div>To tackle the issues of poor surface quality, grinding burn, microcrack and deformation in conventional grinding, in this paper, combined the merits of ultrasonic vibration and electrolytic grinding, the material removal characteristics of GCr15 steel in longitudinal torsional ultrasonic electrolytic internal grinding were revealed based on the kinematic analysis of single abrasive particle. Additionally, a theoretical analysis of the heights of material removed by electrolytic action and mechanical grinding was conducted. The single factor experiments were completed for conventional grinding (CG), longitudinal torsional ultrasonic grinding (LTUG), electrolytic grinding (EG) and longitudinal torsional ultrasonic electrolytic grinding (LTUEG). The results demonstrated the superiority of LTUEG processing through comparisons with CG, LTUG and EG. LTUEG shows significant advantages in reducing grinding force, improving surface roughness and quality, and achieving ideal microhardness and residual stress. The formation and removal mechanism of the passivation film were elucidated. The passivation film was primarily composed of iron oxides, hydroxides, and precipitates of the C element. Increasing the voltage helped to increase the thickness of the passive film and reduce the actual grinding depth; however, excessively high voltages could easily lead to residual passive film coverage and electrolytic burn phenomena. The influence of different processing parameters on surface quality was investigated. Within a certain range, increasing the ultrasonic amplitude, voltage, and grinding wheel speed, while decreasing the feed speed, had a beneficial effect on enhancing the surface quality. Therefore, LTUEG is an effective processing method to improve the quality of GCr15 steel.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"291 ","pages":"Article 110188"},"PeriodicalIF":7.1,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143715062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Composition and layered co-continuous structure co-regulate shape memory properties","authors":"Feng Yang ,&nbsp;Haofan He ,&nbsp;Jiye Jia ,&nbsp;Ping Wu ,&nbsp;Pei Feng ,&nbsp;Cijun Shuai","doi":"10.1016/j.ijmecsci.2025.110187","DOIUrl":"10.1016/j.ijmecsci.2025.110187","url":null,"abstract":"<div><div>4D printed shape memory implant is highly promising for the realization of minimally invasive, while challenged by the poor shape memory effect (SME) of commonly used biodegradable shape memory polymer (SMP) such as poly(L-lactic acid) (PLLA) and thermoplastic polyurethane (TPU). Herein, the shape memory bone scaffold was fabricated by laser powder bed fusion (LPBF) with layered co-continuous structures containing PLLA and TPU. And SME of the scaffold was ameliorated by regulating the material composition and constructing a special layered co-continuous structure for the first time. The layered co-continuous structure could avoid the impact of morphology on SME due to the immiscibility between PLLA and TPU, thus broadening the window of tuning the SME. As the ratio of PLLA and TPU decreased gradually, the shape fixity ratio (R_f) decreased and the shape recovery ratio (R_r) increased. This was attributed to the combination of changes in the ratio of \"switching segment and netpoint\" and the reverse stiffness effect between PLLA and TPU. Besides, due to the efficient stress transfer in the layered co-continuous structure, the R_f and R_r would be considerably changed only when the content threshold of the switching segment or netpoint was reached. A good SME was obtained when the ratio of TPU to PLLA was 2:1, with R_f of 96.5 % and R_r of 96.71 % compared to the pure PLLA. Additionally, the scaffold exhibited sufficient compressive strength and benign cytocompatibility. This study proposed a new and simple but effective strategy to prepare bone scaffold with excellent shape memory properties.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"291 ","pages":"Article 110187"},"PeriodicalIF":7.1,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143726281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of charge carriers on elastic waves in piezoelectric semiconductors","authors":"Wanli Yang ,&nbsp;Songliang Zhang ,&nbsp;Lingyun Guo,&nbsp;Yuantai Hu","doi":"10.1016/j.ijmecsci.2025.110180","DOIUrl":"10.1016/j.ijmecsci.2025.110180","url":null,"abstract":"<div><div>The performance of piezotronic devices is primarily governed by the interaction between elastic waves and charge carriers. Therefore, understanding the underlying mechanisms of this interaction in piezoelectric semiconductors is crucial for the research and development of piezotronic devices. Unlike in purely elastic or piezoelectric media, an elastic wave propagating in a piezoelectric semiconductor involves two interdependent physical processes: the evolution process of thermodynamic state, and the vibration state of elastic wave-front. The former is from the evolution of carrier behavior and the latter is related to the dynamic characteristics of polarization electric field. The mutual competition between two dynamic processes stimulates the interaction between electric field and charge carriers, i.e., appearing a field-particle coupling wave (FPCW). This coupling wave is useful in remaking elastic wave-front characteristics to develop new acoustoelectric devices or to prompt performance of piezoelectric semiconductor devices. Thus, a multi-field coupling dynamic model is established to analyze the relationship between polarized electric field and charge carriers at the elastic wave-front. Furthermore, the distinct coupling mechanisms of these processes at varying vibration frequencies are examined. It is found that a vibration state of an elastic wave-front was altered by the corresponding thermodynamic state most severely at a low-frequency situation, significantly at a medium-frequency one and almost none at a high-frequency one. Correspondingly, a FPCW becomes most pronounced due to strong competition between two dynamic processes in a medium-frequency situation, and very weak in the other two ones. Furthermore, it is revealed in the paper that the nonlinear behavior in drift current is to transfer energy to higher order vibration modes instead of being consumed as claimed from the harmonic analysis technique. These findings are of great significance for designing passive delay line filters, amplifiers, and circulators, etc.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"291 ","pages":"Article 110180"},"PeriodicalIF":7.1,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143734831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dual-sensor blade tip timing with multi-source information and adaptive dictionary update","authors":"Wenkang Huang ,&nbsp;Haifeng Hu ,&nbsp;Yongmin Yang ,&nbsp;Zifang Bian ,&nbsp;Minghao Pan ,&nbsp;Bohao Xiao ,&nbsp;Fengjiao Guan","doi":"10.1016/j.ijmecsci.2025.110178","DOIUrl":"10.1016/j.ijmecsci.2025.110178","url":null,"abstract":"<div><div>Blade tip timing (BTT) has emerged as a critical non-contact vibration measurement technique, increasingly supplanting traditional strain gauge methods for monitoring the operational safety of high-speed rotating machinery, such as aircraft engines and gas turbines. Despite its advantages, conventional BTT approaches face several limitations: undersampling often leads to the loss of high-frequency signals; the requirement for multiple sensors and stringent layout specifications escalates system complexity and cost; and dependence on a single displacement data source restricts the extraction of comprehensive vibration features. Furthermore, traditional BTT methods lack adaptability to varying operating conditions, impeding accurate signal reconstruction. To overcome these challenges, this study proposes a novel dual-sensor BTT sparse reconstruction method. This approach leverages multi-source information, including both displacement and velocity data, to adapt to diverse operating conditions. It employs a dynamic dictionary update process based on the primary frequency range during sparse reconstruction, eliminating the need for at least four sensors to reconstruct synchronous vibration signals under constant speed conditions. This innovation reduces sensor layout constraints and enhances the robustness and accuracy of signal reconstruction. The proposed method is experimentally validated using dual capacitive and dual eddy current sensors for vibration signal identification. The results indicate that integrating multi-source information significantly improves the accuracy and reliability of vibration signal reconstruction, rendering the method highly effective for health monitoring and fault diagnosis in high-speed rotating machinery.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"291 ","pages":"Article 110178"},"PeriodicalIF":7.1,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143715061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Configuration performance of main shaft bearings for transient-loaded wind turbine","authors":"Shuai Cheng ,&nbsp;Xianghui Meng ,&nbsp;Jiabao Yin ,&nbsp;Liang Yang ,&nbsp;Jiajia Zhang","doi":"10.1016/j.ijmecsci.2025.110171","DOIUrl":"10.1016/j.ijmecsci.2025.110171","url":null,"abstract":"<div><div>Wind turbine (WT) main shaft bearings are currently dominated by rolling bearings. However, as the power capacity of WT increases, sliding bearings with lower cost and higher reliability present a more advantageous alternative. During the gradual application of sliding bearings, issues of high friction and wear have emerged. Due to the lack of tribological analysis methods for main shaft sliding bearings, it is difficult to reveal their friction and wear mechanisms and conduct optimized design. To address this, a novel and systematic 6-degree-of-freedom tribo-dynamic model for the main shaft sliding bearing system is developed, incorporating the elastic deformation of composite bearing pads. Based on this model, the effects of various pad configurations of segmented journal/thrust bearings on the tribo-dynamic performance under startup wind loads are analyzed. The results indicate that transient wind loads place the main shaft in a low-speed, high-load state, leading to a decline in oil film lubrication performance during the startup phase. Under these conditions, the 9-Pad journal bearing creates a more compatible radial clearance between shaft and pads, enhancing oil film performance and reducing surface contact. This improvement is attributed to the deformation at the edges of composite pads. The thrust bearing pad configurations affect both the dynamics of main shaft and the tribology of journal/thrust bearings, with the 6-Pad showing certain advantages. These findings can provide guidance for the configuration design of sliding bearings in WT main shaft.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"293 ","pages":"Article 110171"},"PeriodicalIF":7.1,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adaptive sound insulation of piezoelectric metastructure shells around ring and coincidence frequencies","authors":"Huaibing Yuan ,&nbsp;Yisheng Zheng ,&nbsp;Wujun Feng ,&nbsp;Yegao Qu ,&nbsp;Yajun Luo ,&nbsp;Huageng Luo","doi":"10.1016/j.ijmecsci.2025.110175","DOIUrl":"10.1016/j.ijmecsci.2025.110175","url":null,"abstract":"<div><div>To address the soundproof limitations of conventional shells around the ring and coincidence frequencies, this study proposes and investigates a locally resonant piezoelectric metastructure shell (meta-shell) for sound insulation. An electrical-mechanical-acoustic coupling model of the meta-shell is established using the plane-wave expansion method (PWEM). The sound transmission loss (STL) of the meta-shell is computed analytically and further validated through finite-element simulations. It is found that, under oblique incidence of sound waves, the meta-shell exhibits obvious enhancement of STL around the ring and coincidence frequencies when the piezoelectric shunting is properly tuned. The dispersion relations of elastic waves and sound waves are analyzed to elaborate the sound-insulation mechanism. Furthermore, it is demonstrated that the STL around the ring and coincidence frequencies can be improved simultaneously when the high-order resonant shunting circuits are introduced. Due to the high tunability of piezoelectric shuntings, the meta-shell could maintain superior sound-insulation performance under varying incidence angles of sound waves and Mach numbers of fluids, which inevitably lead to the shift of coincidence frequencies. It is not easy for mechanical meta-shells to adapt to such varying conditions. Overall, this research provides physical insights of sound insulation of locally resonant piezoelectric meta-shells, offering valuable guidance for designing smart acoustic skins of aircrafts.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"293 ","pages":"Article 110175"},"PeriodicalIF":7.1,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143678240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Solitary-wave-based deep learning for compressive strength estimation in cementitious materials","authors":"Sangyoung Yoon ,&nbsp;Boohyun An ,&nbsp;Chan Yeob Yeun ,&nbsp;Ernesto Damiani ,&nbsp;Malik Khalfan ,&nbsp;Tae-Yeon Kim","doi":"10.1016/j.ijmecsci.2025.110170","DOIUrl":"10.1016/j.ijmecsci.2025.110170","url":null,"abstract":"<div><div>This study presents a novel deep learning (DL)-based approach for predicting the compressive strength of cementitious materials using highly nonlinear solitary waves (HNSWs) as input data. The proposed method leverages convolutional neural networks (CNNs) to classify compressive strength of mortar by transforming continuous measurements into discrete categories. Four different formats of HNSW signals are explored to evaluate the impact of signal preprocessing on model performance. Multiple mode testing is implemented to enhance the robustness of predictions, using multiple signals from the same class to reduce variability and stabilize results. The DL models were tested on datasets varying by water-to-cement (w/c) ratios and hydration time, achieving superior performance through signal slicing and frequency-domain transformations. Notably, the model achieved high prediction accuracy, with R² values up to 0.989 and RMSE as low as 0.930 MPa, demonstrating its reliability for predicting compressive strength in cementitious materials. Comparative analyses with benchmark architectures such as AlexNet, GoogleNet, and ResNet-18 highlight the effectiveness of the tailored CNN model, which consistently outperforms these benchmarks, especially in multiple mode testing.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"291 ","pages":"Article 110170"},"PeriodicalIF":7.1,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical prediction of vortex-induced vibrations of a long flexible cylinder with variable cross-sections","authors":"Jian Tan ,&nbsp;Chen An ,&nbsp;Shuai Cui ,&nbsp;Songlin Gao ,&nbsp;Renjie Yang ,&nbsp;Segen F. Estefen","doi":"10.1016/j.ijmecsci.2025.110176","DOIUrl":"10.1016/j.ijmecsci.2025.110176","url":null,"abstract":"<div><div>Long flexible cylinders with variable cross-sections are extensively used in engineering applications, yet their vortex-induced vibration (VIV) behavior under linear shear flow remains insufficiently investigated. This study proposes a novel semi-analytical method that integrates the Sturm-Liouville Eigenvalues using Theta Matrices (SLEUTH method) with the Generalized Integral Transform Technique (GITT), enabling efficient and highly accurate VIV predictions. This approach addresses the computational challenges of traditional numerical methods while accurately capturing key structural responses including the structural displacement, structural frequency, displacement envelope, and displacement evolution. Validation against existing experimental data and finite element simulations confirm the method's superior accuracy and computational efficiency. Results reveal that variations in cross-section significantly influence VIV behavior. Tapered, waist-shaped, and stepped cylinders exhibit distinct displacement distributions and frequency responses under shear flow conditions. Tapered cylinders experience amplified displacements in regions with increasing flow velocity, waist-shaped cylinders exhibit localized vibration attenuation, and stepped cylinders display abrupt transitions in displacement envelopes at geometric discontinuities. These findings lay a robust theoretical framework for analyzing VIV in variable cross-section structures, providing essential design guidance for mitigating flow-induced vibrations in offshore and marine engineering applications.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"293 ","pages":"Article 110176"},"PeriodicalIF":7.1,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}