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超弹性薄膜拉伸起皱与再稳定

超弹性薄膜拉伸起皱与再稳定

2018年全国固体力学学术会议

作者：汪婷傅晨玻徐凡霍永忠 m.potier-ferry 复旦大学航空航天系力学与工程仿真研究所 University of Lorraine CNRSArts et Métiers ParisTech

单轴拉伸下的超弹性薄膜通常会失稳起皱,且在过度拉伸时褶皱消失。我们从解析和数值上探讨这种起皱与再稳定的非线性分岔行为,研究不同超弹性本构模型(如Saint-Venant Kirchhoff,neo-Hookean和mooney-Rivlin)对后屈曲失稳形貌演化的影... 详细信息

单轴拉伸下的超弹性薄膜通常会失稳起皱,且在过度拉伸时褶皱消失。我们从解析和数值上探讨这种起皱与再稳定的非线性分岔行为,研究不同超弹性本构模型(如Saint-Venant Kirchhoff,neo-Hookean和mooney-Rivlin)对后屈曲失稳形貌演化的影响。研究结果表明材料本构对分岔响应的影响较小。然而,泊松比在起皱与再稳定的非线性失稳过程中起着至关重要的作用。我们发现较小的泊松比会导致较滞后的褶皱出现,更低的失稳振幅和较早的褶皱消失(再稳定)行为。特别地,当泊松比低于一个阈值时,薄膜在单轴拉伸时不会出现褶皱。这可以通过随着泊松比变小而逐渐衰减的横向压应力来解释。此外,基于Koiter屈曲理论,通过对弹性势能变分后二次项符号的变化,我们半解析地预测了中心分岔点(Isola-center bifurcation),理论预测与有限元结果相吻合。

关键词：超弹性薄膜后屈曲泊松效应起皱与再稳定大应变

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慢变傅立叶系数法研究

慢变傅立叶系数法研究

中国计算力学大会'2010（CCCm2010）暨第八届南方计算力学学术会议（SCCm8）

作者：余堃胡衡 N.Damil m.potier-ferry 武汉大学土木建筑工程学院

本文通过分析非线性文克尔地基梁在压应力作用下发生屈曲褶皱现象时的失稳模式、临界载荷以及褶皱幅度等参数,深入研究了新近提出的慢变傅立叶系数法在解决具有近似周期性变化特性的稳定性问题时的计算效率及应用局限。

关键词：慢变傅里叶系数法屈曲褶皱宏观缩减模型边界效应

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曲率与褶皱

曲率与褶皱

Liberica coffee as an alternative cropping system for sustainable farming on Indonesian Peatlands

2018年全国固体力学学术会议

作者：徐凡杨易凡戴晖辉 m.potier-ferry 复旦大学航空航天系力学与工程仿真研究所香港城市大学数学系 University of Lorraine CNRSArts et Métiers ParisTech

轻轻挤压桌上一张A4纸时,整个纸张在桌面上隆起形成波浪状;撸起袖子或眨眼睛时,则会在袖子或眼睑上出现各种复杂褶皱。这类现象都可归纳为软薄膜在硬基底上面内受压产生的非线性失稳变形。然而,撸起的袖子所呈现出的失稳模态远比平面纸... 详细信息

轻轻挤压桌上一张A4纸时,整个纸张在桌面上隆起形成波浪状;撸起袖子或眨眼睛时,则会在袖子或眼睑上出现各种复杂褶皱。这类现象都可归纳为软薄膜在硬基底上面内受压产生的非线性失稳变形。然而,撸起的袖子所呈现出的失稳模态远比平面纸张(零曲率)屈曲时复杂,其本质原因在于曲率的作用。为探索曲率与褶皱的关系,我们通过实验、计算和理论分析轴向受压的柱面软壳在硬基底上的非线性变形演化全景。我们发现一个新颖的后屈曲响应,即光滑(smooth)-褶皱(wrinkle)-凸脊(ridge)-松垂(sagging)的多重分岔失稳行为。柱壳在临界载荷下首先失稳形成正弦形轴对称褶皱。进一步压缩下,周期性的褶皱将产出二次分岔,向局部化的凸脊形模态转变。当载荷达到第三个分岔点时,凸脊的挠度达到极限,随后由于对称性破缺倒向一边而发生松垂偏转。我们发现在褶皱-凸脊和凸脊-松垂转变的阶段分别存在迟滞现象(hysteresis),即存在maxwell应变。另外,这种多重分岔失稳行为具有普适性,主要依赖于几何非线性而非材料非线性。研究结果为软薄膜表面形貌的力学调控与设计提供了新的思路。

关键词：薄膜失稳后屈曲分岔对称性破缺形貌演化大变形

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International Journal of Agricultural and Biological Engineering 2024年第1期17卷 180-188页

作者： Bariot Hafif Yulius ferry Budi martono Rita Harni Kurnia Dewi Sasmita Busyra B.Saidi maswar maswar R.Bambang Heryanto Novizar Nazir Fahmuddin Agus meynarti Sari Dewi Ibrahim National Research and Innovation Agency Research Center for Estate CropsIndonesia National Research and Innovation Agency Research Center for Food CropsIndonesia Faculty of Agricultural Technology Andalas UniversityIndonesia

Indonesian peatlands are a fragile ecosystem,and to protect it,growing Liberica coffee is a promising way for both the environment and the *** study aimed to evaluate the performance of the liberica coffee on peatland with different water tables and develop an improved cultivation system in this *** study area was in Tanjung Jabung Barat District,Jambi Province,*** plant age is greater than 15 years and the average plant density was about 1000 trees/*** study was conducted in two *** 1st stage was a survey to identify and characterize smallholder liberica coffee farming at three peatland zones,namely 0-100 m,200-300 m,and>400 m from the principal drainage canal,and the 2nd stage was a field experiment to test the effectiveness of amendments in improving liberica coffee growth and improving degraded *** treatments were arranged in a randomized complete block design with four replications,including manure(m),at the rate of 10 t/hm^(2);lime(L),3 t/hm^(2);peat surface elevation(P),and a farmer’s practice(Control)without manure and/or lime as a *** research revealed that liberica coffee can not tolerate high water table as it may stimulate disease incidence and cause low-quality ***,recycling of organic C of about 17.14 t/(hm^(2)·a)through cherry residue application and litter compensated part of the loss of organic C through CO_(2)emissions,coffee bean removal,and maintaining peat fertility for sustainable *** low yield of(0.70±0.12)t/(hm^(2)∙a)coffee bean could be increased to(0.87±0.24)and(0.94±0.14)t/(hm^(2)∙a)by adding 3 t/(hm^(2)∙3a)of lime or 10 t/(hm^(2)∙a)of manure,*** research revealed that water table management and amendments are two main factors in liberica coffee farming on *** is of great significance to study the cultivation technology of coffee in peatland.

关键词： degraded peat amendments water table cultivation system liberica coffee alternative cropping system sustainable farming Indonesian Peatlands

Crystallization of mg-based bulk metallic glass

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中国有色金属学会会刊：英文版 2006年第4期16卷 833-837页

作者：陈刚 m. ferry School of materials Science and Engineering Jiangsu University Zhenjiang 212013 China School of materials Science and Engineering Univers ity of New South Wales Sydney NSW 2054 Australia

mg-based bulk metallic glass fabricated by conventional copper mould method was aged at different temperatures. X-ray diffractometry(XRD), scanning electron microscopy(SEm), atomic force microscopy(AFm) and focused ion beam(FIB) miller were employed to examine specimens obtained under different conditions. The crystallization of mg-based bulk metallic glass depends upon both the aging temperature and the aging time. As temperature increases or the holding time increases, the microstructure of the aged specimen varies from glassy one to crystalline one plus glassy phase and then to absolutely multiphase crystalline one. From the FIB images, it is clear that mg-based bulk metallic glass could not only crystallize completely but also display dendrite-like growth style. From the AFm images, there are not only significant variations of microstructures but also surface morphology of specimens obtained under different conditions. It is proposed that the surface morphology varies as the treating temperature increases. The Vickers hardness of different specimens increases as the fraction of crystalline phase (s) increases.

关键词：镁合金大块金属玻璃结晶化显微结构

Probing the formation of ultrastable metallic glass from structural heterogeneity

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Journal of materials Science & Technology 2022年第9期104卷 214-223页

作者： Qijing Sun Davidm miskovic michael ferry School of materials Science and Engineering The University of New South WalesSydneyNSW 2052Australia

Ultrastable metallic glasses(SmGs)exhibit enhanced stability comparable to those of conventional glasses aged for thousands of *** ability to understand why certain alloy compositions and processing conditions generate an SmG is an emerging ***,amplitude-modulation dynamic atomic force microscopy was utilized for tracking the structure of Zr_(50)Cu_(50),Zr_(50)Cu_(44.5)Al_(5.5)and Zr_(50)Cu_(41.5)Al_(5.5)mo_(3) thin film metallic glasses(TFmGs)that were produced by direct current magnetron sputtering at room temperature with the rate of deposition being the only *** transition in stability from bulkto SmG-like behavior resides in the change of relaxation mechanism as the deposition rate is *** formation of SmGs is directly linked with the degree of structural heterogeneity,whereby mGs with greater heterogeneity have a higher potential to form SmGs with more significant enhancement in *** deposition rates,however,are required to yield the more homogenous structure and lower energy state underlying the *** is closely linked with the geometric shape and distribution of loosely packed phases,whereby SmGs containing more slender loosely packed phases with a more skewed distribution achieve more significant improvements in *** work not only provides direct evidence of the structure of SmGs,but also opens new horizons for the design of SmGs.

关键词： Ultrastable metallic glass Structural heterogeneity Relaxation dynamics Amplitude-modulation dynamic atomic force microscopy

Additive manufacturing of bulk metallic glasses:Fundamental principle,current/future developments and applications

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Journal of materials Science & Technology 2022年第24期119卷 131-149页

作者： H.R.Lashgari m.ferry S.Li School of materials Science and Engineering UNSW Materials and Manufacturing Futures InstituteUniversity of New South WalesSydney NSW 2052Australia

As an advanced manufacturing technique,the advent of additive manufacturing(Am) has opened a new horizon of alternative ways to tackle the challenge of fundamental limits for manufacturing bulk metallic glasses(BmGs).In particular,selective laser melting(SLm),direct metal deposition(DmD),electron beam melting(EBm),and laser foil printing(LFP) have been used for producing BmGs with dimensions larger than what is possible using conventional techniques such as melt-spinning,suction-casting,die-casting,*** this review,we analyzed the current status,issues,structural evolution,and key properties of BmGs based on these emerging Am *** aim is to outline a direction for the development of BmGs using Am technology,establishing a fundamental principle to optimize processing parameters for designing alloy compositions with the high glass-forming ability(GFA),and thermal stability against *** will provide the fundamental science underpinning the future development of Am technology in the fabrication of high-density,defect-free,and completely amorphous alloy components and devices.

关键词： Bulk metallic glass Additive manufacturing Thermal stability Alloying system Process parameters

Phase Selection in Solidi?cation of Undercooled Co–B Alloys

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Journal of materials Science & Technology 2017年第4期33卷 352-358页

作者： X.X.Wei W.Xu J.L.Kang m.ferry J.F.Li State Key Laboratory of metal matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240.China Australian Research Council Centre of Excellence for Design in Light metals School of Materials Science and EngineeringThe University of New South WalesSydneyNSW 2052Australia

A series Co-（18.5–20.7） at.% B melts encompassing the eutectic composition（Co81.5B18.5） were solidified at different degrees of undercooling. It is found that the metastable Co23B6 phase solidifies as a substitute for the stable Co3 B phase in the alloy melts undercooled above a critical undercooling value of -60 *** Co23B6 and α-Co phases make up a metastable eutectic. The corresponding eutectic composition and temperature are Co80.4B19.6 and 1343 K, respectively. On exposure of the metastable Co23B6 phase at a given temperature above 1208 K, it does not decompose even after several hours. But it transforms by a eutectoid reaction to α-Co ＋ Co3 B at lower temperature.

关键词： Undercooling Rapid solidi?cation metastable phase diagram Structure evolution

Soil metagenome of Tropical White Sand Heath Forests in Borneo:What Functional Traits Are Associated with an Extreme Environment Within the Tropical Rainforest?

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Pedosphere 2019年第1期29卷 12-23页

作者： Dorsaf KERFAHI Binu m.TRIPATHI Johan W.ferry SLIK Rahayu S.SUKRI Salwana JAAFAR Ke DONG matthew Chidozie OGWU Hyo-Ki KIm Jonathan m.ADAmS Department of Biological Sciences Seoul National University Korea Polar Research Institute Faculty of Science Universiti Brunei Darussalam College of Natural Sciences Kyonggi University Celemics Inc.612 Avison Biomedical Research Center Yonsei Medical Center Division of Agrifood and Environment School of Water Energy and Environment Building 52a Cranfield University

White sand heath forests(WS) or kerangas, an unusual variant of tropical forests in Borneo, characterized by open scrubby vegetation, low productivity, and distinctive plant species composition and soil microbial community, are regarded as a stressful lowpH and/or nutrient environment. We investigated whether the functional soil metagenome also shows a predicted set of indicators of stressful conditions in WS. Based on stress-tolerant strategies exhibited by larger organisms, we hypothesized that genes for stress tolerance, dormancy, sporulation, and nutrient processing are more abundant in the soil microbiota of WS. We also hypothesized that there is less evidence of biotic interaction in white sand soils, with lower connectivity and fewer genes related to organismic interactions. In Brunei, we sampled soils from a WS and a normal primary dipterocarp forest, together with an inland heath, an intermediate forest type. Soil DNA was extracted, and shotgun sequencing was performed using Illumina HiSeq platform, with classification by the metagenomics Rapid Annotation using Subsystem Technology(mG-RAST). The results, on one hand, supported our hypothesis(on greater abundance of dormancy, virulence, and sporulation-related genes). However, some aspects of our results showed no significant difference(specifically in stress tolerance, antibiotic resistance, viruses, and clustered regularly interspaced short palindrome repeats(CRISPRs)). It appears that in certain respects, the extreme white sand environment produces the predicted strategy of less biotic interaction, but exhibits high soil microbiota connectivity and functional diversity.

关键词： antibiotic resistance biotic interaction kerangas microbial community microbiota shotgun metagenomics stress tolerance tropical forest