Investigation of the nonuniform distribution of the elastic and strength characteristics over the cross section of the diaphysis of the human tibia

The elastic, deformation, and strength properties of six different zones of the cross section of the diaphysis of the human tibia have been experimentally investigated. It is shown that when the compact bone tissue is stressed in tension all these properties differ significantly from zone to zone. The greatest values of the initial modulus of elasticity and the tensile strength correspond to the frontal-outer zones of the bone. The nonlinear stress-strain curves are analytically approximated. The secant and tangent moduli are shown to depend on the stress intensity.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 5, pp. 940–946, September–October, 1971.     

Degree of deformation and strength of compact bone tissue during torsion

This paper discusses the variation in the deformation and strength properties of compact bone tissue during torsion in various zones of the cross section of human tibia. A correlation has been found between the specific energy of deformation consumed during the loading process and the level of stress attained. The degree of correlation between the deformation and strength properties of the bone tissue has been studied as a function of the concentration of certain biochemical substances in its composition.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No.5, pp. 911–918, September–October, 1973.     

Lateral strain coefficients of human compact bone tissue

The values of all the lateral strain coefficients of the compact bone tissue of the human tibia have been experimentally determined. The variation of these coefficients in six zones of the cross section have been studied at various stress levels, including the ultimate strengths in the corresponding directions. It has been established that the bone tissue possesses orthotropy of the elastic properties. The change in the volume of the bone tissue during deformation has been studied. The bulk moduli for both uniaxial and hydrostatic loading have been determined. A bulk deformation parameter characterizing the strain energy expended in producing a volume change of 100% is introduced. The coefficients of the rank correlation between the lateral strain coefficients and bulk moduli, on the one hand, and the concentrations of a number of biochemical substances found in bone tissue, on the other, are analyzed.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 6, pp. 1089–1100, November–December, 1973.     

Determination of the elastic characteristics of compact bone tissue by investigation of the natural vibration frequency

The dynamic elastic H and shear G_dyn moduli of compact bone tissue have been determined by investigating the natural vibration frequency of specimens obtained from long tubular human bones. The modulus of elasticity E has also been determined by conducting mechanical bending tests. The value of the H modulus is found to change in the course of storage.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 1, pp. 167–172, January–February, 1971.     

Hardness of the human tibia

The hardness distribution over the compact bone tissue of the human tibia is examined along the length and in six different zones of the cross section of the bone. A correlation is established between the hardness numbers, on the one hand, and the characteristics of the mechanical properties and the biochemical composition of the bone tissue, on the other. The three-dimensional structure of the equal-hardness formations is studied. The results confirm the assumptions of [1] concerning the specific functions of each zone in the rheological adaptation of the bone to physiological loads.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga; Scientific Research Institute of Traumatology and Orthopedics, Riga. Translated from Mekhanika Polimerov, No. 6, pp. 1101–1107, November–December, 1973.     

The anisotropy of compact bone material

From the measurements of the main elements of the microstructure of compact bone material, it is concluded that the theoretical model of a transtropic material can be applied to bone tissue. This conclusion is confirmed by the experimental data obtained on compression. The correlation connection between the ultimate strength of compact bone material and the elasticity modulus has been found. It is shown that the anisotropy of the compact material is satisfactorily described by the tensor formula.Scientific-Research Institute of Medical Radiology, Academy of Medical Sciences of the USSR, Obninsk. S. M. Kirov Leningrad Order of Lenin Wood Technology Academy. Translated from Mekhanika Polimerov, No. 4, pp. 711–716, July–August, 1972.     

Differences and correlations between the elastic characteristics of the compact bone tissue of the human tibia

Pair t tests have been carried out on experimental data indicating nonuniformity of the distribution of the elastic properties of the compact bone tissue over the cross section of the human tibia. The elastic characteristics obtained by nondestructive and destructive testing have been subjected to a linear correlation analysis. It is shown, with statistical reliability, that the compact bone tissue has a degree of anisotropy of the elastic properties higher than transverse isotropy.     

Age aspects of the torsional strength of compact bone tissue

The variation of the strength of specimens of human tibial compact bone tissue with age has been investigated. It is shown that the torsional strength _i ^* increases sharply in childhood, reaches a maximum at age 25–35, and then gradually falls. There is a correlation between _i ^* and the porosity of the bone tissue. The mode of fracture of the bone tissue has been studied in relation to its orientation with respect to the principal axes of anisotropy.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 3, pp. 493–503, May–June, 1975.     

Change in the mechanical properties of human compact bone tissue upon aging

The ultimate tensile strength σ_z, elastic modulus E, maximum deformation ?, and Brinell hardness H_B of human compact bone tissue were determined. The contents of the minerals calcium and phosphorus, nitrogen, and water (relative to mass and volume), as well as the density were studied in the same bone samples. It was found that all the characteristics studied changed with increasing age. It is emphasized that various types of destructive mechanisms are characteristics of different ages.     

Dependence of elastic and strength characteristics of high-modulus composites on schemes of reinforcement

The elastic and strength characteristics of high-modulus composites with 12 different reinforcement schemes have been studied thoroughly. The effect of reinforcement schemes on change in elastic and strength characteristics of composites has been evaluated. A calculation of the elastic characteristics of high-modulus composites has been performed from the properties of the reinforcement and binder, and a comparison of the results with experimental data is given. Diagrams of deformation upon extension of the composites studied are given.All-Union Scientific-Research Institute of Aviation Materials, Moscow. Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 6, pp. 1019–1027, November–December, 1974.     

Deformability and strength of compact bone tissue during tensioning

The deformability and strength characteristics of compact bone tissue of human tibia during tensioning along all three main anisotropy axes was determined experimentally. The character of change in the secant moduli of elasticity and specific energies of deformation during the loading process were studied. A correlation was established between the mechanical characteristics and the biochemical composition of the bone tissue.     

Elastic and strength characteristics of a glass-reinforced plastic in compression

The elastic constant and strength characteristics in compression have been experimentally determined for a cold-cured glass-reinforced plastic in the direction of all three principal axes of anisotropy. It is shown that the elastic constants obtained satisfy the constraints imposed on orthotropic materials by the thermodynamic relations.Translated from Mekhanika Polimerov, No. 5, pp. 866–869, September–October, 1970.     

Strength and reliability of cylindrical shells prepared by the method of continuous filament winding

Conclusions 1. Strength calculation of shells whose material has a scatter in elastic and strength characteristics should be carried out using statistical methods. A deterministic calculation using values of elastic and strength characteristics leads to appreciable errors in the estimate of bearing ability.2. The problems of estimating the strength and the reliability of constructions from laminar composites are closely interconnected.3. Physicomechanical characteristics of a material which have been obtained in tests of unidirectional specimens make it possible to describe the behavior of a construction on the condition that the structure of the shell layer material is reduced to the structure of the specimen material.4. Allowing for the scale effect plays an important role in estimating the reliability and bearing ability of heavy-duty shells for large-size pressure vessels.Translated from Mekhanika Polimerov, No. 3, pp. 443–451, May–June, 1978.     

Resistance of bony tissue to tensile fracture

The tensile fracture resistance of compact bony tissue is considered. The relation between specific strain energy and stress level is established. A strength criterion characterizing the degree of deformation is proposed on the basis of a model, according to which compact bony tissue may be regarded as a composite material. The mode of variation of the proposed resistance parameter over the various zones of the cross section of the diaphysis of a human tibia has been experimentally established.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 6, pp. 1084–1091, November–December, 1971.     

Some features of bone tissue deformation under unloading and repeated laoding

Conclusions 1. There is a change in the initial elastic properties of compact bone tissue when a load is removed after repeated loading.2. The elasticity modulus after the load has been removed can be assumed to be independent of the level of stress _11k at which the load was removed.3. With repeat loadings, the tangential elastic modulus increases for the same level of stress when the off-loading stress _11k is increased.4. The value of the irreversible expended specific energy of deformation W increases sharply as the moment of destruction approaches, while its distribution through the zones of the cross section of bone provides good rheological adaptation of the bone to external loads in human walking.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 5, pp. 882–890, September–October, 1976.     

Effect of moisture content on the microdeformation of compact bone tissue in tension

Conclusions The x-ray diffraction results indicate the following major features for the microdeformation of bone tissue. The total deformation in the elastic region is determined by the microdeformation of the mineral bone tissue component. The large yield of the mineral component indicates its relatively low elasticity modulus. The shape of the deformation curves for both dry and moist bone tissue is a factor of the combined deformation of the mineral and organic components. While the total deformation up to fracture in dry bone tissue is determined largely by microdeformation of the crystalline mineral phase, such behavior is found for moist bone tissue only in the first segment of the curve. Deformation in the second, more curved segment of the deformation curve is a factor largely of deformation of the organic bone-tissue component.Translated from Mekhanika Kompozitnykh Materialov, No. 3, pp. 530–535, May–June, 1983.     

Variation of certain mechanical properties of human compact bone tissue with age

The nature of the variation of the moduli of elasticity, shear moduli, and flexural and torsional decrements of human compact bone tissue during biological aging has been investigated. It has been found that the moduli of elasticity and shear moduli increase sharply up to age 20–25 and then progressively fall; the distribution of the modulus of elasticity over the individual zones of the cross section of the tibia changes significantly with age. By investigating the changes in the logarithmic decrements by nondestructive methods it is possible to estimate the changes in the mechanical and structural properties of the bone.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 5, pp. 885–891, September–October, 1974.     

Technology and Some Mechanical Properties of Biocomposites Based on Mineral Components

Two types of new composite implant materials are investigated. Their mechanical characteristics, biocompatibility, and the dynamics of bond strength between the biocomposites and a live bone tissue are determined. The first type of the biomaterials is based on silicate glass and hydroxyapatite. Both the natural and a synthetic hydroxyapatite were used. The second type of the biomaterials was made of an ultrahigh-molecular polyethylene and the synthetic hydroxyapatite. Composite materials of both the types were implanted in the rabbit femur. The bond strength between the bone tissue and the implants was determined in 2, 4, 10, and 25 weeks.__________Translated from Mekhanika Kompozitnykh Materialov, Vol. 41, No. 2, pp. 273–282, March–April, 2005.     

Determination of some dynamic characteristics of forming bone callus by the induced vibration method

Conclusions 1. Upon maturation, bone callus not only goes through a series of morphological chantes but also changes in mechanical properties. This is true primarily for an increase in the elasticity modulus.2. The specific energy of dispersion and loss modulus have maxima which occur after 25 to 30 days. This behavior is apparently related to the fact that bone callus at this period has the nature of spongy bone tissue. For compact bone tissue, on the other hand, these values are equal to zero.3. The area of the hysteresis loop is almost completely independent of the frequency upon cyclic stressing.4. The elasticity modulus is proportional to the x-ray density of the samples, which thus may serve as an objective criterion of the degree of maturity of callus.Smolensk State Medical Institute. Translated from Mekhanika Polimerov, No. 5, pp. 896–900, September–October, 1977.     

Correlations between the velocities of ultrasonic surface waves and the characteristics of the mechanical properties of human bone tissue

The correlation between the ultrasonic surface wave velocities in the human tibia, on the one hand, and the characteristics of the mechanical properties of compact bone tissue, the ultrasonic longitudinal wave velocities, and the principal biochemical components of the bone, on the other, has been investigated. The regression equations obtained make it possible to estimate the state of the bone tissue on the basis of the data of one of the most convenient methods of nondestructive materials testing.