Analysis of the elastic-plastic indentation properties of materials with varying ratio of hardness to Young’s modulus

The elastic-plastic indentation properties of materials with varying ratio of hardness to Young’s modulus(H/E) were analyzed with the finite element method. And the indentation stress fields of materials with varying ratio H/E on the surface were studied by the experiment. The results show that the penetration depth, contact radius, plastic pile-up and the degree of elastic recovery depend strongly on the ratio H/E. Moreover, graphs were established to describe the relationship between the elastic-plastic indentation parameters and H/E. The established graphs can be used to predict the H/E of materials when compared with experimental data.

Biodegradation of Polymethylmethacrylate Bone Cement May Not Be a Serious Issue in Total Hip Arthroplasty—Retrieval Study for Knoop Hardness and Young’s Modulus

Introduction: To investigate a long-term in vivo deterioration of polymethylmethacrylate (PMMA) bone cement over time, we evaluated retrieved PMMA cement in terms of chemical elements presenting in the cement using energy dispersive analysis of X-rays;Knoop hardness;and the Young’s modulus using scanning acoustic microscopy. Materials and Methods: For mechanical evaluation, we could neglect the influences of entrapped air bubbles or blood by the use of small specimens. The study was based on thirteen cement samples (six used in the acetabulum and seven in the femur) derived from eight patients (age at revision surgery: mean 72.5, range 68 to 79). All of these samples were Simplex-P?cement. They were functioning well at least ten years after the previous surgery. Duration until revision surgery was ranged 12 to 25 years (average, 17.4 years). The reason for revision was aseptic mechanical loosening. Twenty samples of Simplex-Preg;cement were served by manually mixing as a control. Results: The average of the hardness of the cement was 17.0 ± 1.2 (range, 13.4-20.6). In the control, the hardness was 17.8 ± 1.5 (range, 14.0-24.6). There was no significant difference between these values. The mean of Young’s modulus of the cement was 5.61 ± 0.19 GPa (range, 5.09-6.10). In the control, the modulus was 6.04 ± 0.13 GPa (range, 5.68-6.45). Although the modulus was significantly less than that of the control, there was only 7% decrease in average between twelve and twenty-five years in vivo. Conclusions: Our results suggest that long-term implantation and functional loading in vivo may not be the limiting factor in the mechanical integrity of the bone cement.

Quantitative Determination of Material Hardness

The paper contains description of a new quantitative method of evaluation of material hardness. First the essence of cognition subject, concerned with the hardness notion, has been discussed. Next some characteristics of exemplary existing evaluation methods have been presented. Then the attention was paid to the mistakes present in understanding//reasoning of the discussed problem. The revolutionary new method is given in the next part of the paper by presenting functional and parametric characteristics of the process of local deformation of a material. At the end, the justification – with the essential meaning for investigations of present and newer materials – to introduce one unified quantitative method of hardness evaluation, has been delivered.

Full-Heusler合金V2MnGa磁性和力学性能

利用第一性原理计算方法,对Full-Heusler合金V 2MnGa整体结构进行了优化,并在最优的晶格常数的基础上计算磁矩,并绘制能带结构图,分析V 2MnGa的磁学性质,以及计算V 2MnGa的力学性能,通过计算合金的体积模量B,Voigte-Reusse-Hill平均剪切模量G、泊松比ν和杨氏模量Y,证明V 2MnGa化合物属于延展性合金。计算V 2MnGa各向异性因子A为2.01,说明该化合物不是弹性各向同性的。结果表明,V 2MnGa合金平衡态晶格常数为5.74(7),属于半金属材料,力学性能表明该合金具有较好的延展性。

HfO_2-SiO_2混合膜力学性能

利用离子辅助电子束双源共蒸发工艺方法,制备了SiO_2掺杂含量分别为0、13%、20%、30%、40%和100%的六组HfO_2-SiO_2混合膜。采用纳米压痕法测量了不同组分混合膜的杨氏模量和硬度,并研究了混合膜杨氏模量和硬度随SiO_2含量增长的变化规律。结果显示,随着SiO_2含量增加,混合膜杨氏模量和硬度均减小,双组分复合材料并联模型可以较好地拟合杨氏模量随混合膜SiO_2含量变化关系。为了解释混合膜力学性能随SiO_2含量变化规律,对混合膜进行了XRD测试,研究了混合膜微观结构与杨氏模量和硬度的关系,发现结晶对硬度影响显著,对杨氏模量影响较小;用Zygo干涉仪测量了样品的面形,获得了薄膜残余应力随SiO_2含量的变化规律,表明SiO_2掺杂能减小HfO_2薄膜压应力。

实时剪切波弹性成像检测甲状腺结节杨氏模量值及Ratio值鉴别良恶性的临床价值

目的探讨剪切波弹性成像（SWE）检测甲状腺结节杨氏模量值及Ratio值鉴别良恶性的价值。方法选取2014年10月~2015年1月在本院手术治疗的39例甲状腺实性结节患者作为研究对象,术前均行SWE检测,记录甲状腺组织弹性杨氏模量的平均值（E_（mean））、最小值（E_（min））及最大值（E_（max））及以颈前肌为参照的Ratio值,应用ROC曲线分析杨氏模量值（最大值）及Ratio值在甲状腺结节良恶性鉴别中的价值。结果良、恶性结节的杨氏模量值（最大值）及Ratio值比较,差异有统计学意义（P〈0.05）,ROC曲线下面积（AUC）分别为0.90、0.81。结论 SWE可定量测量甲状腺组织的杨氏模量值及Ratio值,获得客观的组织硬度信息,能够为甲状腺疾病的诊断提供更多依据。

基底材料对MoS2的应变场影响

利用有限元法分析对生长在Au、Cu、Al2O3、SiO2、Ni这5种不同基底上的层状MoS2的应变分布进行模拟仿真.研究结果表明:基底材料的泊松比不同会使得基底和MoS2的y方向形变都不相同;基底的杨氏模量不同会使得不同基底底部与二硫化钼(MoS2)顶部的应变差别不同.在膨胀过程中,y方向底端的拉伸应变大于中间的拉伸应变,这会导致基底与顶端应变高于中间的应变.因此,基底材料的杨氏模量和泊松比与MoS2的应变分布密切相关.根据仿真结果可得,由于MoS2在Au和SiO2基底上所受到的应变较小,导致MoS2的顶端和基底底部应变差较大,因此容易造成剥离脱落;而在Al2O3基底上,由于基底材料具有较高的杨氏模量,且与MoS2比较接近,所以MoS2顶端和基底底部呈现的应变差接近.由此可见,在这些材料当中,Al2O3更适合作为MoS2的基底材料.通过研究基底材料的应变场分布,能更好地对纳米材料进行调控,从而改善器件的相关性能.

A methodology to determine the elastic properties of anisotropic rocks from a single uniaxial compression test

This paper introduces a new methodology to measure the elastic constants of transversely isotropic rocks from a single uniaxial compression test.We first give the mathematical proof that a uniaxial compression test provides only four independent strain equations.As a result,the exact determination of all five independent elastic constants from only one test is not possible.An approximate determination of the Young’s moduli and the Poisson’s ratios is however practical and efficient when adding the Saint-Venant relation as the fifth equation.Explicit formulae are then developed to calculate both secant and tangent definitions of the five elastic constants from a minimum of four strain measurements.The results of this new methodology applied on three granitic samples demonstrate a significant stress-induced nonlinear behavior,where the tangent moduli increase by a factor of three to four when the rock is loaded up to 20 MPa.The static elastic constants obtained from the uniaxial compression test are also found to be significantly smaller than the dynamic ones obtained from the ultrasonic measurements.

Study of Rock Mechanic Property and Mineralogy Relationship of the Huai Hin Lat Formation, Sap Phlu Basin, Northeastern Thailand: Implications for Understanding of Shale Gas Reservoir Rock

Thailand is lacked of gas that more information of probable (P2) and possible (P3) reserve data including shale gas can be acceptable to prove (P1) reserve data for new gas field. This research had implicated for understanding of unconventional reservoir rock by rock mechanical, micro-CT, and geochemistry analysis of the Huai Hin Lat Formation. The rock mechanical analysis is composed of average young’s modulus, Poisson’s ratio, and compressive strength of 1933.79 MPa, 0.1472, and 52.56 MPa. The average porosity of 6.89% consists of 5.41% and 1.48% of closed and open porosities. The average mineralogical results consist mainly of 57.60% and 42.40% of brittle and ductile minerals indicating more elasticity except Bed 6. The Bed 6 is significantly higher quartz (15%) and brittle minerals (64%) indicating to easier fracture are, therefore, lower compressive strength (25.93 MPa), young’s modulus (1729.10 MPa) and Poisson’s ratio (0.0705). The Beds 3B is slightly higher clay containing slightly higher closed porosity (5.46%) but the Bed 14 is slightly higher brittle mineral indicating to slightly higher open porosity.

The Effect of Stem Diameter on the <i>Brassica napus</i>(Type: Canola) (Cultivar: HYHEAR 3) Fiber Quality

A matured canola plant has different types of stems based on the diameter, such as narrow (immature), medium (mature), and wide (over mature). Therefore, this study was focused on investigating the properties of the extracted canola (HYREAR 3) fibers from 3 different diameter of stems (narrow, medium and wide). The physical (average length, aspect ratio, contact angle, and moisture regain) and mechanical (load at break, elongation at break, tensile stress, young’s modulus, and tenacity) properties of fibers were measured. ANOVA showed that stem diameter had effects on all fiber properties except for average length and elongation at break. Fiber diameter also had significant effects on load at break, elongation at break, aspect ratio, tensile stress, and young’s modulus. In corrgram, it was found that tensile stress, young’s modulus, and aspect ratio were negatively correlated to fiber diameter whereas load at break and tenacity were positively associated. Mean values showed that stem diameter had effects on all fiber properties except for average length. The mean values of fiber diameter, load at break, elongation at break, tenacity, and contact angle were highest and the lowest mean values were observed for tensile stress, young’s modulus and aspect ratio in fibers of 7 - 10 mm stems (medium matured), hence found to be less stiff. Moisture regain ability showed that canola fibers isolated from ≥8 mm stem diameter were more hydrophobic whereas contact angle measurement showed relatively more hydrophobic nature of 7 - 10 mm stem fibers. Therefore, this study provided an insightful understanding of the quality of the canola fibers of different stems which will ultimately help to choose the best stem to extract different qualities of fibers for commercial uses.

Observation of a Chemical Softener’s Effects on Stem-Specific Lignocellulosic <i>Brassica napus</i>(Type: Canola) (Cultivar: HYHEAR 3) Fiber Quality

Chemical softener (Cepreton UN) is used to soften the cellulosic fiber (cotton) in the textile industries to make clothes better to touch. Therefore, this study investigated the effects of Cepreton UN on both physical (length, aspect ratio, contact angle, and moisture regain) and mechanical (load at break, elongation at break, tensile stress, young’s modulus, and tenacity) properties of the lignocellulosic canola (HYREAR 3) fibers extracted from narrow, medium, and wide stems. ANOVA showed that fiber diameter had strong effects on elongation at break, load at break, tensile stress, young’s modulus, and aspect ratio for all fibers. Corrgram values showed that tensile stress, young’s modulus, and aspect ratio were negatively correlated to fiber diameter whereas load at break and tenacity were mostly positively correlated to fiber diameter. The fibers were treated with 2% and 10% Cepreton UN and compared with control fibers. In most cases, the fiber diameter was decreased in both 2% and 10% treated medium stem fibers. The mean values of elongation at break, load at break, tenacity, and contact angle were decreased for 10% and increased for 2% and the mean values of tensile stress, young’s modulus, and aspect ratio were decreased for 2% and increased for 10% treated medium stem fibers. Moisture regain (%) mostly decreased for 2%, and increased for 10% treated fibers. Low pH (4.5) had an almost similar effect on fibers as 2% Cepreton UN. Overall, 2% Cepreton UN treatment is found to be better than 10% to make canola fibers less stiff and low pH was found to be an alternative softener treatment strategy.

基于纳米压痕技术的岩石力学参数评价

为评价使用小岩心样品获取岩石力学参数,计算岩石脆性指数的可靠性,提出基于纳米压痕实验技术获取岩石力学参数的方法.使用1 mm×1 mm的小尺度岩心碎样或岩屑获得岩石的力学参数,通过纳米压痕技术进行矿物相分析和压痕实验,利用卷积方法进行尺度升级,求取宏观力学参数.采用该方法对致密油岩屑样品的力学实验结果与岩心柱塞的三轴岩石力学实验结果相比,误差绝对值小于10%,满足脆性指数计算的需要.纳米压痕技术可使用岩心碎样或岩屑获得岩石力学参数,为脆性指数评价的实验参数获取提供了新的技术方法.

基于岩石纵波与横波测试及测井数据的页岩气藏脆性评价方法及应用

作为一种清洁能源,页岩气的开发在中国得到了迅速的发展,中石化焦石坝和高邮凹陷区块是中国页岩气勘探区块比较成功的案例。相对于常规油气藏来说,页岩气的开发较为复杂,影响页岩气开发的因素较多,其中,储层的岩石物理性质是影响页岩气藏能否成功开发的关键因素之一。为了提示岩石物理性质对页岩气开发的影响规律,本文开展了系统的研究。首先,从页岩气层的岩心中钻出5个样品(直径2.5厘米,长度为4~6厘米),放入水中进行充分饱和,然后将饱和水的样品放入HR2500-2高速冷冻离心机中,分别使用8种速度进行脱水,得到不同含水饱和度的样品。其次,在模拟地层条件下,使用CTS-45非金属超声检测分析仪确定每个样品在不同含水饱和度下的纵波和横波速度,最后将实验数据与岩石力学参数的计算方法相结合,计算得到泊松比、杨模量、脆性指数等一系列关键参数。利用上述方法对高邮凹陷块5口井的岩样进行了分析,结果表明:杨氏模量越高,泊松比越低,脆性越高,可压性越高。并总结出了E1F4每个小层可压性,可以对各个小层的压裂设计进行科学的指导。

岩石动静力学参数的试验研究

在三轴应力下对砂、泥岩等岩芯（干岩样）进行了岩石力学参数的动、静态同步测试，并对动静态弹性参数进行了线性回归。结果表明：岩石的动静态杨氏模量之间存在较好的相关性，而动静态泊松比之间的关系不明显，该项研究为岩石的声学性质在石油工程中的应用提供了实验依据。

川东北地区地层条件下致密储层力学性质实验分析

利用“MTS岩石物理参数测试系统”对四川盆地东北部埋藏深度3200m～4200m的上三叠统须六段以及中侏罗统凉高山组和沙一段储层垂直和平行层理方向的岩石样品进行了模拟地层条件(包括围压、孔压、温度、孔隙饱和介质等)下的力学性质测试。实验结果显示,所有样品都表现为脆性特征,破坏前轴向总应变均小于2%。须六段、凉高山组和沙一段的抗压强度均值分别为394.2MPa,173.5MPa和524.6MPa;杨氏模量均值分别为57.0GPa,35.6GPa和53.7GPa;泊松比均值分别为0.219,0.275和0.208。岩石组成和结构是决定岩石力学性质的内在因素,随着岩石中泥质含量和孔隙度的降低,以及石英类碎屑含量的增加,岩石抗压强度和杨氏模量均增加,而泊松比的变化较为复杂;当岩样中含有先存薄弱面时,其抗压强度和杨氏模量明显降低。多数情况下,平行层理方向样品的抗压强度和杨氏模量大于垂直层理方向,而泊松比则刚好相反。孔隙水对岩石力学性质具有显著影响,饱水样品的泊松比明显大于干燥样品。

阴极电沉积法制备高氮含量氮化碳薄膜

用双氰胺在乙腈中的溶液作沉积液 ,以镀有铟锡氧化物 (ITO)的导电玻璃为衬底 ,在阴极上制备了高氮含量的CNx 薄膜。XPS分析表明 ,薄膜最高氮碳原子比N/C为 1 2 2 (接近C3 N4中氮碳计量比 ) ,碳和氮主要以C—N、CN的形式成键。FTIR支持XPS的分析结果。拉曼光谱与大多数报道的氮化碳的拉曼光谱不同 ,在 10 98和 195 0cm -1处有 2个明显的峰 ,前者可归属为C—N ,后者可归属为 CN 。在 5 0℃、12 5 0V下得到的样品薄膜的纳米硬度为 11 31GPa ,弹性模量为 86GPa。提出了极化竞争反应机制 ,简要的解释了CNx

致密储层敏感弹性参数叠前同步反演方法

杨氏模量和泊松比是表征致密储层脆性的重要弹性参数,而Gassmann流体项则是地震流体识别中常用的流体因子。利用叠前地震反演方法从叠前地震资料中同步获取此类参数是可行且有效的途径。为此,针对致密储层预测及流体识别的需要,提出了一种致密储层敏感弹性参数叠前同步反演的新方法。在孔隙弹性介质反射系数近似方程的基础上,通过重新组合变化,推导出包含杨氏模量、泊松比、Gassmann流体项及密度参数的纵波反射系数方程,建立起了杨氏模量、泊松比、Gassmann流体项及密度反射率与纵波反射系数间的线性关系。在此基础上,采用基于贝叶斯理论的弹性阻抗反演技术,提出了杨氏模量、泊松比、Gassmann流体项及密度参数的叠前同步反演方法。模型数据试算和实际资料测试结果均表明,所提出的方法能够从叠前地震资料中稳定地获取致密储层的敏感弹性参数,为此类储层的预测及流体识别提供了一种可靠的技术途径。

地层条件下CX盆地地表岩样动弹参数的实验分析

对云南ＣＸ盆地采集的地表露头岩样，在模拟地层环境的温度、压力（孔压和围压）条件下测量了岩石的纵横波速度和各种动弹参数（包括体积压缩模量、杨氏模量、剪切模量和泊松比等），根据测试结果研究了该地区岩石的动弹参数的变化规律，以及地层埋深、温度、压力等因素对动弹参数的影响。

砂岩弹性参数与波速关系的实验研究

为进一步了解岩石弹性参数(如杨氏模量、泊松比)与超声波波速的关系,将岩石加卸载循环实验和超声波测量实验同时进行,得到同一组样品的测量数据并作对比分析。实验结果表明,应力的变化会导致岩石样品的孔隙度、裂隙、岩石结构和构造的改变。受这些因素的影响砂岩的杨氏模量、泊松比、波速,也都会有规律地变化。较低应力水平时用小循环加卸载测得的动态弹性模量是不准确的,计算的波速也不准确,只有通过波速实验才能准确测出;饱水情况的加卸载纵波波速之差比干燥情况小,饱水波速大于干燥波速;动态泊松比比较稳定,但静态泊松比随着应力的增加而增加,从0.07增加到0.12,有趋近于动态泊松比的趋势;用P-M模型从微观概率分布入手,能够很好地解释静态和动态弹性参数的差别。通过本实验,采用回归分析的方法,成功建立起了岩石介质中弹性参数与波速的关系,为类似实验提供参考依据。

三轴应力下饱和水砂岩动静态弹性参数的试验研究

建立了一套试验装置，以解决含水岩样变形的电阻应变片测量问题，并实现有孔隙压力的三轴应力下饱和水岩样纵、横波速度和变形的同步测试，通过时８块砂岩岩样的测试，初步得出了饱和水砂岩波速和动静态弹性参数随应力状态变化的基本规律，给出了岩石静态弹性模量和静态泊松比随岩石密度、孔隙度和围压等参数变化的多元线性回归关系式，并对动、静态弹性参数间的关系进行了初步分析。