正常人皮质骨压缩力学性能实验研究

本文对６例正常青年男性（平均年龄３０岁左右）新鲜股骨干中段皮质骨，沿外侧纵向及横向各截取３６个圆柱体标本，行标本轴向压缩力学性能试验，结果显示，股骨中段皮质骨在纵、横两个不同方向上的力学性能具有很大差异。在相同载荷水平下，沿股骨干轴线方向的弹性模量、屈服强度、极限强度、屈服应变均明显高于横向（垂直于股骨轴线方向）。纵、横向弹性模量、屈服强度、极限强度、屈服应变的比值分别为１．５７、１．８８、１．３５、１．４８（Ｐ＜０．０００１）。经统计学分析，沿纵向骨的能量吸收值也明显高于横向（Ｐ＜０．０００１）。充分证明皮质骨是一种各向异性的非均质材料，为临床上骨创伤移植、及固定器械的研制提供重要的实验数据。     

密质骨的滑动界面细观力学模型

本文将粘合线作为骨单元和间板之间的粘弹性界面,建立了密质骨的细观力学模型,并给出了该模型在滑骨的轴线方向载荷作用下的应力响应和某些密质骨的宏观等效模量。还发现骨单元和间板的泊松比之差对密质骨的等效模量和内部横向应力的分布具有重要影响。     

跟骨、月骨、头状骨松质骨粘弹性实验研究

研究了跟骨、月骨、头状骨松质骨的粘弹性力学性质。对跟骨松质骨纵向、横向、4 5°方向和月骨、头状骨松质骨进行压缩应力松弛、蠕变实验。得出了跟骨松质骨纵向、横向、4 5°方向和月骨松质骨、头状骨松质骨压缩应力松弛、蠕变数据和曲线。用回归分析的方法处理实验数据 ,得出了归一化应力松驰函数 ,蠕变函数及曲线。实验结果表明跟骨松质骨纵向压缩应力松弛、蠕变量均大于横向和 4 5°方向 ;头状骨松质骨初始蠕变量大于月骨松质骨 ,月骨与头状骨 2 h内蠕变量、松弛量差异并不显著。     

皮质骨在拉伸型、剪切型和撕裂型加载条件下的断裂韧性──纵向断裂和横向断裂的比较

对牛皮质骨在拉伸（Ⅰ型）、剪切（Ⅱ型）和撕裂（Ⅲ型）型载荷下的裂纹启裂韧性进行了研究。总数为130个紧凑拉伸试样，紧凑剪切试样和三腿型试样分别用于测量骨的拉伸型、剪切型和撕裂型启裂韧性。多试样柔度法用来测定当a／W＝0．55（a，裂纹长度，W，试样宽度）时的临界能量释放率（Gc）。临界应力强度因子（Kc）由a／W＝0．55的试样在试验中得到的临界载荷（PQ）来计算。为了考察骨力学性质的各向异性对于它的剪切型和撕裂型裂纹启裂韧性的影响，对骨试样的裂纹扩展方向平行于（纵向断裂）和垂直于（横向断裂）长骨的纵向轴线时的裂纹启裂韧性进行了比较。在纵向启裂情况下，拉伸型，剪切型和撕裂型临界能量释放率（Gc）分别为644±102，2430±836，and1723±486N／m。在横向断裂情况下，拉伸型，剪切型和撕裂型临界能量释放率（Gc）分别为1374±183，4710±1284，and4016±948N／m。统计分析表明，无论纵向断裂或横向断裂，皮质骨的剪切型和撕裂型裂纹启裂韧性显著高于其拉伸型裂纹启裂韧性。我们的结果同时也表明，皮质骨的结构使得它更有效地防止垂直于骨的纵向轴线的裂纹启裂和失稳扩展。     

影响人腰椎松质骨不同水平段力学性质的几个因素

本文以新鲜人腰椎椎体松质骨为材料，利用ＩＮＳＴＲＯＮ万能电子试验机进行了纵向及横向加载方向下的松质骨压缩试验，并比较了两组的表现密度（ｐｔ），组织密度（ｐｔ），弹性模量（Ｅ），极限应力（σｕ）和终应变（εｕ）。试验结果表明，两组间的表观密度，组织密度及终应变均无明显差异而纵向加压组的弹性模量及极限应力均显著高于横向加压组。因此作为各向异性材料的松质骨，不同的加载方向将对试验结果产生显著影响。     

人湿尺骨对冲击载荷的响应

本文采用分离式Ｈｏｐｋｉｎｓｏｎ压杆（ＳＨＰＢ）技术对人湿润尺骨密质骨进行了应变率在ε＝１．２×１０３Ｓ－１条件下的冲击压缩试验，得到了不同纵向位置尺骨的极限强度、极限应变和压缩模量。实验结果表明，尺骨密质骨的力学响应随其纵向位置变化，呈现中间强两端弱的分布规律，最强的位置约在距近端１／３处，且近端强于远端；与静态结果的比较表明，尺骨密质骨对应变率有较大的依赖性。     

微波高温处理的人皮质骨生物力学性质的研究

目的 :明确微波高温处理的人皮质骨生物力学性质的变化 ,为预防微波介入式高温治疗的骨肿瘤患者病理骨折提供理论依据。方法 :微波高温加热人皮质骨 ,制备力学试样。进行静态拉伸、静态压缩试验。测定强度极限、断裂功 ,延伸率。结果 :微波高温处理 80℃ ,持续 30min ,皮质骨密度下降 5 .5 1%。在加载应变率为 0 .8～1.6× 10 -4s-1条件下 ,进行静力学试验。微波高温处理人皮质骨静拉伸强度无明显下降 ,压缩强度比正常皮质骨提高约 2 3%。显微硬度比正常湿润皮质骨提高 4 6 %。延伸率下降 4 3.2 % ,断裂功下降。结论 :微波高温损害了皮质骨的韧塑性 ,使骨组织脆性增加 ,易突发断裂。     

国人股骨下端松质骨力学性质实验研究

对正常国人新鲜尸体股骨下端松质骨的拉伸、压缩、扭转、剪切、弯曲、冲击等力学性能进行实验研究,得出了股骨下端松质骨纵向的拉伸、压缩破坏载荷、强度极限、弹性模量,扭转破坏扭矩、扭转剪切强度极限,扭转剪切弹性模量,剪切破坏载荷、剪切强度极限,弯曲破坏载荷、弯曲强度极限,冲击功、冲击韧性指标.对松质骨的取样方法及松质骨拉伸,扭转试样固定装夹方法进行探讨.对股骨下端松质骨的力学性质进行分析讨论.     

股骨颈松质骨三方向压缩应力松弛蠕变实验

研究正常国人新鲜尸体股骨颈松质骨的压缩粘弹性力学性质,为人工关节的研制提供生物力学理论基础.对10具正常国人新鲜尸体股骨颈松质骨纵向、横向、45°方向试样进行压缩应力松弛、蠕变实验.得出了股骨颈松质骨3个方向的应力松弛、蠕变数据和曲线.对实验数据进行归一化处理,分别用对数、指数一元回归分析的方法处理数据,得出了归一化应力松弛、归一化蠕变函数及曲线.说明股骨颈松质骨纵向组应力松弛量、蠕变量均大于横向组和45°方向组.股骨颈松质骨为各向异性材料.     

皮质骨试样制备及其材料参数识别方法研究

有限元方法已经成为损伤生物力学研究的重要手段,准确的皮质骨材料本构参数对研究人体冲击损伤和人工骨骼等医学问题具有重要意义。基于长骨皮质骨的生理结构,提出批量制备高精度规则试样的加工方法,并开展准静态三点弯曲试验;采用基于梁理论和基于特定样本有限元模型优化反求两种方法,研究皮质骨材料的各向异性和区域差异,并通过线性回归分析建立两种识别方法所得材料参数的回归模型。制备横向和轴向试样各16个,所提出的试样制备方法能够保证试样间的尺寸偏差不超过4%,基于梁理论方法求得的新鲜牛股骨皮质骨轴向和横向试样的杨氏模量分别为(21.70±3.33) GPa和(14.47±2.10) GPa,极限应力分别为(249.21±38.83) MPa和(106.81±21.05) MPa,极限应变分别为1.95%±0.35%和1.06%±0.20%,与文献结果吻合。对利用优化方法和梁理论方法求得的杨氏模量、屈服应力和有效塑性应变进行线性回归分析,回归模型拟合精度分别为96.4%、98.7%和89.3%(P<0.05)。研究结果表明,所提出的试样制备方法能够高效地加工尺寸精度较高的规则试样,并良好地保持试样的生物力学特性。在皮质骨准静态三点弯曲试验中,基于特定样本有限元模型的材料参数反求方法能够识别更准确的材料本构参数,而基于梁理论识别参数的回归模型则能够快速准确地预测皮质骨的弹性模量、屈服应力和有效塑性应变。     

Mechanical implications of collagen fibre orientation in cortical bone of the equine radius

Mechanical test specimens were prepared from the cranial and caudal cortices of radii from eight horses. These were subjected to destructive tests in either tension or compression. The ultimate stress, elastic modulus and energy absorbed to failure were calculated in either mode of loading. Analysis was performed on the specimens following mechanical testing to determine their density, mineral content, mineral density distribution and histological type. A novel technique was applied to sections from each specimen to quantify the predominant collagen fibre orientation of the bone near the plane of fracture. The collagen map for each bone studied was in agreement with the previously observed pattern of longitudinal orientation in the cranial cortex and more oblique to transverse collagen in the caudal cortex. Bone from the cranial cortex had a significantly higher ultimate tensile stress (UTS) than that from the caudal cortex (160 MPa vs 104 MPa; P<0.001) though this trend was reversed in compression, the caudal cortex becoming relatively stronger (185 MPa vs 217 MPa; P<0.01). Bone from the cranial cortex was significantly suffer than that from the caudal cortex both in tension (22 GPa vs 15 GPa; P<0.001) and compression (19 GPa vs 15 GPa; P<0.01). Of all the histo-compositional variables studied, collagen fibre orientation was most closely correlated with mechanical properties, accounting for 71% of variation in ultimate tensile stress and 58% of variation in the elastic modulus. Mineral density and porosity were the only other variables to show any significant correlation with either UTS or elastic modulus. The variations in mechanical properties around the equine radius, which occur in close association with the different collagen fibre orientations, provide maximal safety factors in terms of ultimate stress, yet contribute to greater bending of the bone as it is loaded during locomotion, and thus lower safety factors through the higher strains this engenders.     

Comparison of the structure and mechanical properties of bovine femur bone and antler of the North American elk (Cervus elaphus canadensis)

Antler and limb bone have a similar microstructure and chemical composition. Both are primarily composed of type I collagen and a mineral phase (carbonated apatite), arranged in osteons in compact (cortical bone) sections and a lamellar structure in the cancellous (spongy or trabecular bone) sections. The mineral content is lower in antler bone and it has a core of cancellous bone surrounded by compact bone running through the main beam and tines. The mineral content is higher in the compact compared with the cancellous bone, although there is no difference in ratios of the mineral elements with calcium. Mechanical tests (bend and compression) on longitudinal and transverse orientations of dry and rehydrated compact bone of North American elk (Cervus elaphus canadensis) antlers are compared with known data on other antlers as well as bovine femora. Both dry and rehydrated bones are highly anisotropic, with the bending and compressive strength and elastic modulus higher in the longitudinal than in the transverse direction. There is no significant difference between the bend strength and elastic modulus between dry and rehydrated samples tested in the transverse direction. The elastic modulus measured from the bending tests is compared with composite models. The elastic modulus and bend strengths are lower in the rehydrated condition, but the strain to failure and fracture toughness is much higher compared with dry samples. All antler bone mechanical properties are lower than that of bovine femora. The antler has a much higher fracture toughness compared with bovine femora, which correlates with their main function in intraspecific combat as a high impact resistant, energy absorbent material. A model of compression deformation is proposed, which is based on osteon sliding during shear.     

不同角度载荷下股骨头骨小梁的生物力学特性

目的 探讨不同角度载荷对股骨头骨小梁形态学与力学性能的影响,为研究股骨头坏死、塌陷的生物力学机制提供理论依据。方法 利用12月龄羊股骨头和人尸体股骨头分别制作羊股骨头骨小梁试件94个和人股骨头骨小梁试件43个。按照受力方向与骨小梁主压力方向之间的不同夹角,将骨小梁以10°间隔分为内翻10°、0°和外翻10°、20°、30°共计5组,模拟股骨颈骨折内固定术后不同戈登（Garden）对线指数下的复位情况。通过分别对羊股骨头骨小梁进行micro-CT扫描、计算与压缩破坏试验以及对人尸体股骨头骨小梁进行循环压缩试验,分析不同受力方向下股骨头骨小梁的骨体积分数（BV/TV）、骨表面积/骨体积（BS/BV）、骨小梁平均厚度（Tb.Th）、骨小梁数量（Tb.N）、骨小梁间距（Tb.Sp）等形态学指标以及弹性模量、极限强度、屈服强度、初始弹性模量、循环次数等力学指标。结果 加载方向与骨小梁的主压力方向之间夹角为0°时,BV/TV、Tb.Th以及弹性模量、极限强度、屈服强度、初始弹性模量、循环次数均为最大,而BS/BV与Tb.N为最小,并随着夹角增大前者呈递减而后者呈递增趋势。结论 12月龄羊股骨头骨小梁BV/TV与极限强度随受力方向与骨小梁主压力方向之间夹角变化的趋势与人股骨头骨小梁一致;加载方向与主压力骨小梁之间夹角增大时,股骨头骨小梁形态学与力学性能均下降;Garden指数偏离160°越大时,股骨头内骨小梁越易发生损伤。     

皮持骨在拉伸型,剪切型和撕裂型加载条件下的断裂韧性——纵向断裂…

对以质骨在拉伸、剪切和撕裂型载荷下的裂纹启裂韧性进行了研究。总数为１３０个紧凑拉式样,紧凑剪切试样和三腿型试样分别用于测量骨的拉伸型、剪切型和撕裂型启裂韧性。多试样柔度法用来测定当ａ／Ｗ＝０．５５（１,裂纹长度,Ｗ,试样宽度）时的临界能量释放率。临界应力强度因子由ａ／Ｗ＝０．５５的试样在试验中得到的临界载荷来计算。为了考察骨力学 各是性对于它的剪切型和撕裂裂纹启裂韧性的影响,对骨试样的裂纹扩展方向     

不同角度载荷下股骨头骨小梁的生物力学特性

目的探讨不同角度载荷对股骨头骨小梁形态学与力学性能的影响,为研究股骨头坏死、塌陷的生物力学机制提供理论依据。方法利用12月龄羊股骨头和人尸体股骨头分别制作羊股骨头骨小梁试件94个和人股骨头骨小梁试件43个。按照受力方向与骨小梁主压力方向之间的不同夹角,将骨小梁以10°间隔分为内翻10°、0°和外翻10°、20°、30°共计5组,模拟股骨颈骨折内固定术后不同戈登(Garden)对线指数下的复位情况。通过分别对羊股骨头骨小梁进行micro-CT扫描、计算与压缩破坏试验以及对人尸体股骨头骨小梁进行循环压缩试验,分析不同受力方向下股骨头骨小梁的骨体积分数(BV/TV)、骨表面积/骨体积(BS/BV)、骨小梁平均厚度(Tb.Th)、骨小梁数量(Tb.N)、骨小梁间距(Tb.Sp)等形态学指标以及弹性模量、极限强度、屈服强度、初始弹性模量、循环次数等力学指标。结果加载方向与骨小梁的主压力方向之间夹角为0°时,BV/TV、Tb.Th以及弹性模量、极限强度、屈服强度、初始弹性模量、循环次数均为最大,而BS/BV与Tb.N为最小,并随着夹角增大前者呈递减而后者呈递增趋势。结论 12月龄羊股骨头骨小梁BV/TV与极限强度随受力方向与骨小梁主压力方向之间夹角变化的趋势与人股骨头骨小梁一致;加载方向与主压力骨小梁之间夹角增大时,股骨头骨小梁形态学与力学性能均下降;Garden指数偏离160°越大时,股骨头内骨小梁越易发生损伤。     

不同角度载荷下股骨头骨小梁的生物力学特性

目的 探讨不同角度载荷对股骨头骨小梁形态学与力学性能的影响,为研究股骨头坏死、塌陷的生物力学机制提供理论依据。方法 利用12月龄羊股骨头和人尸体股骨头分别制作羊股骨头骨小梁试件94个和人股骨头骨小梁试件43个。按照受力方向与骨小梁主压力方向之间的不同夹角,将骨小梁以10°间隔分为内翻10°、0°和外翻10°、20°、30°共计5组,模拟股骨颈骨折内固定术后不同戈登（Garden）对线指数下的复位情况。通过分别对羊股骨头骨小梁进行micro-CT扫描、计算与压缩破坏试验以及对人尸体股骨头骨小梁进行循环压缩试验,分析不同受力方向下股骨头骨小梁的骨体积分数（BV/TV）、骨表面积/骨体积（BS/BV）、骨小梁平均厚度（Tb.Th）、骨小梁数量（Tb.N）、骨小梁间距（Tb.Sp）等形态学指标以及弹性模量、极限强度、屈服强度、初始弹性模量、循环次数等力学指标。结果 加载方向与骨小梁的主压力方向之间夹角为0°时,BV/TV、Tb.Th以及弹性模量、极限强度、屈服强度、初始弹性模量、循环次数均为最大,而BS/BV与Tb.N为最小,并随着夹角增大前者呈递减而后者呈递增趋势。结论 12月龄羊股骨头骨小梁BV/TV与极限强度随受力方向与骨小梁主压力方向之间夹角变化的趋势与人股骨头骨小梁一致;加载方向与主压力骨小梁之间夹角增大时,股骨头骨小梁形态学与力学性能均下降;Garden指数偏离160°越大时,股骨头内骨小梁越易发生损伤。     

猪胸主动脉血管各向异性力学性能的实验研究

目的 研究猪胸主动脉血管各向异性的力学特性。 方法 收集21条猪胸主动脉血管并分成3组。沿每条血管的轴向剖开并展成平面,以展开后血管的长方向（即血管轴向）0°为起始角,逆时针方向分别切取30°、 45°、 60°、90°、120°、 135°、 150°、180° 8个角度方向的样本。以1、5、10 mm/min的加载速率分别对3组样本进行单轴拉伸测试,以获得血管样本在8个不同方向及3种加载速率下的弹性模量和极限应力。 结果 不同角度样本的应力 应变曲线呈现出不同的黏弹性行为;随着样本角度的变化,从30°开始,弹性模量逐渐增大,到90°时弹性模量最大,然后逐渐减小,直到180°;极限应力与弹性模量的变化规律基本一致。不同加载速率对弹性模量和极限应力的结果具有明显的影响,但对血管的各向异性度影响较小。结论 猪主动脉血管呈现较强的各向异性,研究结果为有限元分析建模中材料属性的赋值提供参数参考,对理解血管生物力学特性具有重要的意义。     

Fracture toughening mechanism of cortical bone: an experimental and numerical approach

In this investigation, the crack propagation mechanisms contributing to the toughness of cortical bone were studied using a combination of experimental and numerical approaches. Compact tension (CT) specimens were prepared from bovine cortical bones to achieve crack propagation in the longitudinal and transverse directions. Stable crack extension experiments were conducted to distinguish the crack growth resistance curves, and virtual multidimensional internal bond (VMIB) modeling was adopted to simulate the fracture responses. Results from experiments indicated that cortical bone exhibited rising resistance curves (R-curves) for crack extension parallel and perpendicular to the bone axis; the transverse fracture toughness was significantly larger, indicating that the fracture properties of cortical bone are substantially anisotropic. Microscopic observations showed that the toughening mechanisms in the longitudinal and transverse directions were different. When the crack grew in the transverse direction, the crack deflected significantly, and crack bifurcations were found at the crack wake, while, in the longitudinal direction, the crack was straight and uncracked ligaments were observed. Numerical simulations also revealed that the fracture resistance in the transverse direction was greater than that in the longitudinal direction.     

The use of short carbon fibre reinforced thermoplastic plates for fracture fixation

Thermoplastic plates of Nylon 6-10 and Polybutylene terephthalate reinforced with 30% short randomly oriented carbon fibres were tested for internal fixation of canine femoral transverse midshaft fractures. The elastic modulus of the plates was one-half that of bone: however, ultimate strength and strain in bending were comparable to bone. The fractures healed with moderate callus formation which was completely remodelled by 8 to 12 wk post surgery. Although a moderate inflammatory reaction to occasional particulate debris was noted, the materials appeared to possess the proper elastic moduli to allow sufficient support for the healing fracture without protecting the remodelling process.     

Obituary: Eino Kulonen 1921-1984

The microstructure, composition and the micromechanical properties across the thickness of femoral mid-diaphyses from 14 to 26 week human fetuses have been investigated. Scanning electron microscopy and transmission electron microscopy were employed to examine structural changes with maturation. The fetal bones consist of layers of woven bone. From young to old fetuses and from outer to inner bone layers, the collagen fibrils become more cross-linked, densely packed and change from disordered to an ordered arrangement. The collagen fibril bundles are also more preferentially oriented and change from a chiefly circumferential to longitudinal direction. The sizes of the apatite crystals also increase with age. The Ca/P ratio remains constant around 1.55 for all the bone layers except the outmost layer which is lower than 1.2. An nano-indenter was used to evaluate the microhardness and elastic modulus of each bone layer. The increase of microhardness and elastic modulus correlates with the maturation of bone. The mechanical properties of the mid-diaphyses of human fetal femurs are anisotropic, which is due to the preferential orientation of collagen fibrils