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damage tolerance Design of Artificial Mechanical Heart Valve Holder

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Chinese Journal of Biomedical Engineering(English Edition) 2022年第1期31卷 1-12页

作者： ZHANG Jian-hui ZHA Xiao WANG Li-ya School of Mechanical Engineering Hangzhou Dianzi UniversityHangzhou 310018China

To study the conservative life of the artificial mechanical heart valve holder,CATIA software was used for modeling,and ABAQUS finite element analysis was used to analyze the stress of the valve holder in the complex environment of the human body and the residual thermal stress during production and *** damage tolerance method based on fracture mechanics analyzes the maximum initial crack size that the heart valve holder can tolerate under the premise that the structural safety life is longer than the life of the implanted *** results show that the maximum initial crack size is only tens of microns;the traditional S/N life analysis can only obtain non-conservative life,and the damage tolerance method is the basic requirement for analyzing the life and quality control of artificial mechanical heart valves.

关键词： artificial heart valve ABAQUS S/N life analysis damage tolerance maximum initial crack

Developing nacre-inspired laminate-reticular 2024Al/B_(4)C composites with high damage resistance by adjusting compositional wettability

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Transactions of Nonferrous Metals Society of China 2022年第4期32卷 1105-1118页

作者： Yang WANG Qiang LIU Biao ZHANG Hao-qian ZHANG Yi-cheng JIN Zhao-xin ZHONG Jian YE Yu-han REN Feng YE Wen WANG Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China

To address the issue that B_(4)C ceramics are difficult to be wetted by aluminum metals in the composites,TiB_(2)was introduced via an in-situ reaction between TiH_(2)and B_(4)C to regulate their wettability and interfacial *** pressure infiltration of the molten alloy into the freeze-cast porous ceramic skeleton,the 2024Al/B_(4)C-TiB_(2)composites with a laminate-reticular hierarchical structure were *** with 2024Al/B_(4)C composite,adding initial TiH_(2)improved the flexural strength and valid fracture toughness from(484±27)to(665±30)MPa and(19.3±1.5)to(32.7±1.8)MPa·m^(1/2),*** exceptional damage resistance ability was derived from multiple extrinsic toughening mechanisms including uncracked-ligament bridging,crack branching,crack propagation and crack blunting,and more importantly,the fracture model transition from single to multiple crack *** strategy opens a pathway for improving the wettability and interfacial bonding of Al/B_(4)C composites,and thus produces nacre-inspired materials with optimized damage tolerance.

关键词： bio-inspired composites freeze casting titanium hydride mechanical properties damage tolerance

“Wood-nacre”:Development of a Bio-inspired Wood-Based Composite for Beam and 3D-Surface Elements with Improved Failure Mechanisms

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Journal of Bionic Engineering 2023年第4期20卷 1701-1711页

作者： Ulrich Müller Peter Halbauer Alexander Stadlmann Maximilian Grabner Hajir Al-musawi Bernhard Ungerer Maximilian Pramreiter Department of Material Science and Process Engineering Institute of Wood Technology and Renewable MaterialsUniversity of Natural Resources and Life SciencesKonrad-Lorenz-Straße 243430Tulln an der DonauAustria Hycobility Engineering&Technologies GmbH Stadiongasse 6-8/Top281010ViennaAustria

Following the natural structure of the nacre,the material studied consists of a multitude of hexagonal tiles that are glued together in an offset manner with a ductile *** so-called“wood nacre”consists of macroscopic tiles of birch wood veneer with a thickness of 0.8 mm and a size of 20 or 10 mm in diameter in order to mimic the aragonite tiles and the ductile PUR-adhesive corresponds to the layers of collagen in between.E-modulus(MOE),bending strength(MOR)and impact bending strength of the samples were determined and compared with reference samples of birch laminated *** hierarchical layered structure of the tiles does not cause any relevant loss in *** nacre,“wood nacre”also shows tough fracture behaviour and a high homogenization ***,strain hardening and high fracture toughness of the natural model could not be fully *** reason for this is the insufficient ratio between the strength and stiffness of the veneer layers and the *** adjusting the size of the tiles,increasing the strength and surface roughness of the veneers,*** densification,and using more ductile adhesives that can be applied in smaller layer thicknesses,it should be possible to better reproduce the natural ratios of nacre and thus achieve a significant improvement in the material properties of“wood nacre”.In addition to the mechanical properties,the high potential of the new material lies in the possibility of producing 3D shell-shaped elements for lightweight wood hybrid construction.

关键词： Bio-inspired damage tolerance Failure behaviour Hierarchical structure Nacre Work of fracture

High-entropy rare-earth diborodicarbide:A novel class of high-entropy(Y_(0.25)Yb_(0.25)Dy_(0.25)Er_(0.25))B_(2)C_(2)ceramics

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Journal of Advanced Ceramics 2023年第7期12卷 1430-1440页

作者： Huidong Xu Longfei Jiang Ke Chen Qing Huang Xiaobing Zhou Engineering Laboratory of Advanced Energy Materials Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China University of Chinese Academy of Sciences Beijing 100049China

A novel class of high-entropy rare-earth metal diborodicarbide(Y_(0.2)5 Yb_(0.25)Dy_(0.25)Er_(0.25))B_(2)C_(2)(HE-REB_(2)C_(2))ceramics was successfully fabricated using the in-situ reactive spark plasma sintering(SPS)technology for the first *** solid solution with a typical tetragonal structure was formed,having a homogeneous distribution of four rare-earth elements,such as Y,Yb,Dy,and *** of thermal expansion(CTEs)along the a and c directions(aa and ac)were determined to be 4.18 and 16.06μK^(-1),*** expansion anisotropy of the as-obtained HE-REB_(2)C_(2)was attributed to anisotropy of the crystal structure of HE-REB_(2)C_(2).The thermal conductivity(k)of HE-REB_(2)C_(2)was 9.2±0.09 W·m^(-1)·K^(-1),which was lower than that of YB_(2)C_(2)(19.2±0.07 W·m^(-1)·K^(-1)),DyB_(2)C_(2)(11.90.06 W·m^(-1)·K^(-1)),and ErB_(2)C_(2)(12.10.03 W·m^(-1)·K^(-1)),due to high-entropy effect and sluggish diffusion effect of high-entropy ceramics(HECs).Furthermore,Vickers hardness of HE-REB_(2)C_(2)was slightly higher than that of REB_(2)C_(2)owing to the solid solution hardening mechanism of *** nano-laminated fracture morphologies,such as kink boundaries,delamination,and slipping were observed at the tip of Vickers indents,suggesting ductile behavior of HE-REB_(2)C_(2).This newly investigated class of ductile HE-REB_(2)C_(2)ceramics expanded the family of HECs to diboridcarbide compounds,which can lead to more research works on high-entropy rare-earth diboridcarbides in the near future.

关键词： high-entropy rare-earth diboridcarbide (Y_(0.25)Yb_(0.25)Dy_(0.25)Er_(0.25))B_(2)C_(2)(REB_(2)C_(2)) high-entropy ceramics(HECs) thermal property damage tolerance

Density-functional-theory predictions of mechanical behaviour and thermal properties as well as experimental hardness of the Ga-bilayer Mo_(2)Ga_(2)C

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Journal of Advanced Ceramics 2022年第2期11卷 273-282页

作者： Xinxin QI Weilong YIN Sen JIN Aiguo ZHOU Xiaodong HE Guangping SONG Yongting ZHENG Yuelei BAI National Key Laboratory of Science and Technology on Advanced Composites in Special Environments and Center for Composite Materials and Structures Harbin Institute of TechnologyHarbin 150080China School of Materials Science and Engineering Henan Polytechnic UniversityJiaozuo 454003China

Mo_(2)Ga_(2)C is a new MAX phase with a stacking Ga-bilayer as well as possible unusual *** understand this unique MAX phase structure and promote possible future applications,the structure,chemical bonding,and mechanical and thermodynamic properties of Mo_(2)Ga_(2)C were investigated by *** the“bond stiffness”model,the strongest covalent bonding(1162 GPa)was formed between Mo and C atoms in Mo_(2)Ga_(2)C,while the weakest Ga–Ga(389 GPa)bonding was formed between two Ga-atomic layers,different from other typical MAX *** ratio of the bond stiffness of the weakest bond to the strongest bond(0.33)was lower than 1/2,indicating the high damage tolerance and fracture toughness of Mo_(2)Ga_(2)C,which was confirmed by indentation without any *** high-temperature heat capacity and thermal expansion of Mo_(2)Ga_(2)C were calculated in the framework of quasi-harmonic approximation from 0 to 1300 *** of the metal-like electronic structure,the electronic excitation contribution became more significant with increasing temperature above 300 K.

关键词： MAX phase first-principles damage tolerance heat capacity thermal expansion

3D-printed Lunar regolith simulant-based geopolymer composites with bio-inspired sandwich architectures

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Journal of Advanced Ceramics 2023年第3期12卷 510-525页

作者： Siqi Ma Yuqi Jiang Shuai Fu Peigang He Chengyue Sun Xiaoming Duan Dechang Jia Paolo Colombo Yu Zhou Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China Key Laboratory of Advanced Structural–Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China Max Planck Institute for Polymer Research Mainz 5512Germany Laboratory for Space Environment and Physical Sciences Harbin Institute of TechnologyHarbin 150001China Department of Industrial Engineering University of PadovaPadova 35122Italy Department of Materials Science and Engineering The Pennsylvania State UniversityPhiladelphia 16802USA

Over time,natural materials have evolved to be lightweight,high-strength,tough,and damage-tolerant due to their unique biological ***,combining biological inspiration and structural design would provide traditional materials with a broader range of performance and ***,the application of an ink-based three-dimensional(3D)printing strategy to the structural design of a Lunar regolith simulant-based geopolymer(HIT-LRS-1 GP)was first reported,and high-precision carbon fiber/quartz sand-reinforced biomimetic patterns inspired by the cellular sandwich structure of plant stems were *** study demonstrated how different cellular sandwich structures can balance the structure–property relationship and how to achieve unprecedented damage tolerance for a geopolymer *** results presented that components based on these biomimetic architectures exhibited stable non-catastrophic fracture characteristics regardless of the compression direction,and each structure possessed effective damage tolerance and anisotropy of mechanical *** results showed that the compressive strengths of honeycomb sandwich patterns,triangular sandwich patterns,wave sandwich patterns,and rectangular sandwich patterns in the Y-axis(Z-axis)direction were 15.6,17.9,11.3,and 20.1 MPa(46.7,26.5,23.8,and 34.4 MPa),respectively,and the maximum fracture strain corresponding to the above four structures could reach 10.2%,6.7%,5.8%,and 5.9%(12.1%,13.7%,13.6%,and 13.9%),respectively.

关键词： Lunar regolith simulant(LRS) three-dimensional(3D)printing geopolymer(GP) in situ resource utilization(ISRU) bio-inspired patterns damage tolerance

Acorn size and tolerance to seed predators:the multiple roles of acorns as food for seed predators,fruit for dispersal and fuel for growth

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Integrative Zoology 2018年第3期13卷 251-266页

作者： Andrew W.BARTLOW Salvatore JAGOSTA Rachel CURTIS Xianfeng YI Michael ASTEELE Department of Biology and The WIESS Institute for Environmental Science and Sustainability Wilkes UniversityWilkes BarrePennsylvaniaUSA Present address:Department of Biology University of UtahSalt Lake CityUtahUSA Center for Environmental Studies and Department of Biology Virginia Commonwealth UniversityRichmondVirginiaUSA Present address:Department of Veterinary Integrative Biosciences Texas A&M UniversityCollege StationTexasUSA College of Life Sciences Jiangxi Normal UniversityNanchangJiangxiChina.

Fitness of parents and offspring is affected by offspring *** oaks(Quercus spp.),acorns vary considerably in size across,and within,*** size influences dispersal and establishment of oaks,but it is not known whether size imparts tolerance to seed ***,we examine the relative extent to which cotyledon size serves as both a means for sustaining partial consumption and energy reserves for developing seedlings during early stages of *** of 6 oak species were damaged to simulate acorn predation by vertebrate and invertebrate seed *** germination/emergence and growth rates were used to assess seedling *** predicted that if cotyledons are important for dispersal,acorns should show tolerance to partial seed ***,if the cotyledon functions primarily as an energy reserve,damage should significantly influence seedling *** of each species germinated and produced seedlings even after removing>50%of the *** mass explained only some of the variation in *** species,larger acorns performed better than smaller acorns when *** acorns performed as well or better than damaged *** was no pattern among individual species with increasing amounts of *** some species,simulated invertebrate damage resulted in the poorest performance,suggesting alternative strategies of oaks to sustain *** cotyledons in acorns may be important for attracting seed dispersers and sustaining partial damage,while also providing energy to young *** of oak establishment may follow from the resilience of acorns to sustain damage at an early stage.

关键词： acorns damage tolerance dispersal Quercus seed size

A method of predicting visual detectability of low-velocity impact damage in composite structures based on logistic regression model

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Chinese Journal of Aeronautics 2021年第1期34卷 296-308页

作者： Fengyang JIANG Zhidong GUAN Zengshan LI Xiaodong WANG School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China

This paper proposed a new method for quantitative assessment of visual detectability of damage based on logistic regression,using the Probability of Detection(POD)as a *** were performed to establish the massive hit/miss data of visual *** investigations verified the reliability of the *** prediction function concluded comprises more than one flaw size parameters,including the depth and diameter of the *** results show that the depth and diameter of the dents are pivotal for the evaluation of detectability;the type of detection,the detection distance,and the qualifications of personnel are critical external factors to be *** function,with an accuracy rate of nearly 85%,is capable of predicting the visual detection probability of impact damage under various detection environments,which will provide a reference for the damage tolerance design of composite materials and field maintenance in the NonDestructive Testing(NDT)field.

关键词： Composite materials damage tolerance Machine learning NDT Logistic regression

Tensile and fracture properties of Ti-62A alloy plate with different microstructures

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Rare Metals 2012年第5期31卷 420-423页

作者： LIU Rui HUI Songxiao YE Wenjun YU Yang FU Yanyan SONG Xiaoyun DENG Xiguang State Key Laboratory of Nonferrous Metals & Processes General Research Institute for Nonferrous Metals Beijing 100088 China

Ti-62A alloy plates with three different types of microstructure, fully equiaxed, bimodal, and Widmanstatten, were obtained by various heat treatments to investigate the effects of microstructure on the tensile and fracture properties at room temperature. The results reveal that Widmanstatten microstructure exhibits good damage tolerance behavior considering strength, fracture toughness, and fatigue crack growth behavior, while the bimodal microstructure shows good comprehensive properties considering the plasticity synthetically. Optical microscopy (OM) and scanning electron microscopy (SEM) microstructure analyses on fracture and fatigue crack path demonstrate that the dependence of mechanical properties and fatigue crack growth behavior on microstructural feature are attributed to the α lamellae width and the α colony size. © The Nonferrous Metals Society of China and Springer-Verlag Berlin Heidelberg 2012.

关键词： Brittleness damage tolerance Fatigue crack propagation Fatigue of materials Fracture toughness Microstructural evolution Optical microscopy Scanning electron microscopy Tensile properties