Intensity Of Singular Stress Field Research Articles

1431 エンリッチ要素を用いたせん断力下の二次元接合体における特異応力場の強さ(S15-2 界面の強度評価,S15 熱応力,応力特異性と強度評価)

Dissimilar material junctions have singularities created by discontinuities in material properties across an interface. For this reason, it is difficult to predict accurate stress by using conventional FEM. In this study, we tried to apply an enriched finite element method to study the intensity of singular stress fields in case of applied shear loading on its boundary.

Intensity of Singular Stress Fields at the End of a Cylindrical Inclusion

In short fiber reinforced composite it is known that the singular stress at the end of fibers causes crack initiation, propagation, and final failure. The singular stress field is controlled by the generalized stress intensity factors defined at the end of the inclusion. In this study the stress intensity factors are discussed for an elastic cylindrical inclusion in an infinite body under (A) asymmetric uniaxial tension in the x direction, and (B) symmetric uniaxial tension in the z direction. These problems are formulated as a system of integral equations with Cauchy-type or logarithmic-type singularities, where densities of body force distributed in infinite bodies having the same elastic constants as those of the matrix and inclusion are unknown. In the numerical analysis, the unknown body force densities are expressed as fundamental density functions and weight functions. Here, fundamental density functions are chosen to express the symmetric and skew-symmetric stress singularities. Then, the singular stress fields at the end of a cylindrical inclusion are discussed with varying the fiber length and elastic ratio. The results are compared with the ones of a rectangular inclusion under longitudinal and transverse tension.

930 短繊維強化プラスチックスにおける繊維端部の特異応力場の強さ解析

930 短繊維強化プラスチックスにおける繊維端部の特異応力場の強さ解析

426 鋭い V 形切欠きを有する丸棒の曲げおよびねじりにおける特異応力場の強さ

426 鋭い V 形切欠きを有する丸棒の曲げおよびねじりにおける特異応力場の強さ

Intensity of Singular Stress Field at the Notch Tip of a V-Notched Bar.

In this study, generalized stress intensity factors KIII, λ4 are calculated for a V-shaped notched round bar under torsion using the singular integral equation of the body force method. The body force method is used to formulate the problem as a singular integral equation, where unknown functions are densities of body forces distributed in an infinite body. In order to analyze the problem accurately, the unknown functions are expressed as piecewise smooth, functions using a fundamental density and power series, where the fundamental density is chosen to represent the skew-symmetric stress singularity of the form 1/γ1-λ4. Then, generalized stress intensity factors at the notch tip are systematically calculated for various shapes of V-shaped notches. The accuracy of Benthem-Koiter's formula proposed for a circumferential crack is also examined through the comparison with the present analysis.

Analysis of Intensity of Singular Stress Fields at the End of a Cylindrical Inclusion under Asymmetric Uniaxial Tension.

This paper deals with generalized stress intensity factors at the end of an elastic cylindrical inclusion in an infinite body under asymmetric uniaxial tension. These stress intensity factors control singular stress fields at the end of inclusion. The problem is solved on the superposition of two auxiliary loads;(i)biaxial tension and (ii)plane state of pure shear. The problem is formulated as a system of integral equations with Caushy-type or logarithmic-type singularities, where un-knowns are densities of body force distributed in infinite bodies having the same elastic constants as those of the matrix and inclusion. In the numerical analysis, the unknown functions of the body force densities are expressed as fundamental density functions and weight functions. Fundamental density functions are chosen to express the symmetric stress singularity of the from 1/γ1-λ11/γ1-λ3 and the skew-symmetric stress singularity of the form 1/γ1-λ21/γ1-λ4. Then, the singular stress fields at the end of a cylindrical inclusion are discussed with varying the fiber length and elastic ratio. The results are compared with the ones of a cylindrical inclusion under longitudinal tension and the ones of a rectangular inclusion under transverse tension.

Dependence of Stress Singular Fields on Material Combination of Butt-Jointed Plates Subjected Uniform Tension.

The near-tip stress fields around an interface edge of butt-jointed plates subjected uniform tension are analyzed by finite element method. Based on the result the dependence of the singular stress fields around the interface edge on the material combination is discussed. The relation between the exponent of the stress singularity and its intensity is investigated. The uniqueness of the intensity of singular stress fields for Dundurs's parameters is also studied. The equations which is useful for materials selection of joint concerning with the stress singularity are newly developed.

Intensity of Singular Stress Field at the Notch Tip of a V-Notched Bar.

In this study, generalized stress intensity factors KIII, λ4 are calculated for a V-shaped notched round bar under torsion using the singular integral equation of the body force method. The body force method is used to formulate the problem as a singular integral equation, where unknown functions are densities of body forces distributed in an infinite body. In order to analyze the problem accurately, the unknown functions are expressed as piecewise smooth, functions using a fundamental density and power series, where the fundamental density is chosen to represent the skew-symmetric stress singularity of the form 1/γ1-λ4. Then, generalized stress intensity factors at the notch tip are systematically calculated for various shapes of V-shaped notches. The accuracy of Benthem-Koiter's formula proposed for a circumferential crack is also examined through the comparison with the present analysis.

Intensity of Singular Stress Field at the Interface Edge Point of a bonded Beam.

Intensity of Singular Stress Field at the Interface Edge Point of a bonded Beam.

Intensity of Singular Stress Field at the Interface Edge Point of a Bonded Beam

Intensity of Singular Stress Field at the Interface Edge Point of a Bonded Beam

Intensity of Singular Stress Field near the Interface Edge Point of a Bonded Strip.

This paper deals with the singular stress field near the interface edge point in a bonded strip. The stress field around the singular point is described in terms of one constant, Kσ. The parameter Kσis calculated by using the body force method. In the numerical analysis, the singularity of the stress field is characterized by introducing a proper basic density function of the body forces. The use of the basic density function enables one to obtain accurate solutions.

Analysis of Intensity of Singular Stress Field at Fiber End. 2nd Report, Results of Calculation.

In this paper, the singular stress fields near a corner of a fiber are discussed based on the expressions of the stress fields obtained recently by the authors. The stress fields are expressed as a sum of two terms : a symmetric term and a screw-symmetric term. The intensities of singular stress field are calculated by the method developed in the first report. KI, λ1 and KII, λ2 are shown for various elastic constants and aspect ratios of fiber. The singular stresses at the interfaces are discussed on the basic of the results of calculation.

Analysis of Intensity of Singular Stress Field at Fiber End. 1st Report. Method of Analysis.

The singular stress fields near a corner of fiber can be expressed as the sum of two terms: a symmetric term and a screw-symmetric term. The stress singularities for the two terms are different. The intensities of the mode I and mode II singular stress fields are defined in terms of constants KI, λ1 and KII, λ2, respectively. In this study, a new method for calculating KI, λ1 and KII, λ2 based the body force method is developed. In the numerical analysis, the singularities of stress field are characterized by introducing the proper basic density functions of body forces. The use of the basic density functions enables one to obtain accurate solutions. KI, λ1 and KII, λ2 are obtained simply from the values of weights of the density functions at the corner of the fiber.