Experimental study on crack curving propagation in bending beams under impulsive load

方竞,; 姚雪峰,; 熊春阳,

doi:10.1007/bf02487947

Cited by 6 publications

(3 citation statements)

References 4 publications

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“…In the meantime, the mixed-mode stress intensity factors at the crack tip are also obtained from the caustic patterns at the crack tip using equation (5). According to the aforementioned measurement principle of the CGS and the caustics, figures 8(a)-(d) show the evolution of the stress intensity factors K I and K II at the crack tip in a three-point bending specimen for different crack inclinations β = 15 • , 30 • , 45 • , 60 • , respectively.…”

Section: Evaluation Of Mixed-mode Stress Intensity Factormentioning

confidence: 99%

“…Fomitchov and Krishnaswamy [4] designed a compact dual-purpose camera for both shearography and electronic speckle-pattern interferometry to obtain the object's displacement as well as the displacement gradient in one set-up. Fang et al [5] designed a dynamic experimental method combining photoelasticity with caustics for investigating the transient stress states in structures and the crack-tip singular behaviour in polymer materials. Krishnaswamy and Rosakis [6] introduced the method of bifocal caustics to study the crack-tip stress and deformation.…”

Section: Introductionmentioning

confidence: 99%

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Fracture visualization using hybrid optical technique combining coherent gradient sensing (CGS) with caustics

Yao

Wang

Yeh

2005

Meas. Sci. Technol.

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In this paper, a hybrid optical method combining coherent gradient sensing (CGS) with caustics is introduced. The application of hybrid technology to the fracture investigation of three-point bending specimens with the initial inclined edge-crack is performed. Both the shadow patterns of caustics and CGS fringe patterns are simultaneously recorded from the same specimen by different photographic frames. Based on the K-dominance condition, the stress intensity factors at the crack tip are extracted by means of the characteristic size of caustic spot and the fringe order of CGS, respectively. The influences of different crack combinations on fracture characterizations are analysed. These results will be useful in the reliable design and strength evaluation of engineering structures.

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Section: Evaluation Of Mixed-mode Stress Intensity Factormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fracture visualization using hybrid optical technique combining coherent gradient sensing (CGS) with caustics

Yao

Wang

Yeh

2005

Meas. Sci. Technol.

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“…In view of the difficulty of theoretical analysis of composite stress singularity, experimental study with physical justification has become more and more important. Among most experimental techniques, the optical method of caustic has been proved to be very effective for determining the crack tip singularity of isotropic materials and composites [1][2][3][4][5][6][7][8][9]. The shadow optical method of caustics is an experimental technique used in stress-strain analysis of materials and structures, and it is sensitive to stress gradients and suitable for quantifying the crack tip stress concentration problems.…”

Section: Introductionmentioning

confidence: 99%

Influence of material orientation on crack tip stress singularity in orthotropic composites

Yao¹,

Meng²,

Yeh³

2005

Modelling Simul. Mater. Sci. Eng.

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The crack tip (mode I, mode I + II) stress singularities in orthotropic composites are studied by the method of reflective caustic. Based on the caustic parametric equations and its initial curves surrounding the crack tip derived by the elastic crack solutions of composites and the principle of reflective caustic, theoretical caustics and initial curves at mode I and mixed mode (I + II) crack tip of fibre orthotropic composites are simulated. Influences of material orientation on crack tip singularities in composites are analysed. The static experimental caustics of mode I and mixed mode I + II crack tip in composites are obtained when the initial crack direction is parallel to the main axis of the orthotropic material, i.e. θ = 0°. The results indicate that the experimental caustics obtained from the actual fibre composites have a remarkable difference compared with the simulation caustics based on the fracture theory of continuum orthotropic composites, which provide an important physical foundation for understanding the singular stress characterizations at the crack tip of composite materials.

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Inter-contact force analysis of impacted disk assembly by dynamic caustics

Zhang

Fang

2003

Acta Mech Sinica

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The caustic method was utilized to study the contact force transmission in disk assemblies under impact load. The mapping equations were obtained based on the first invariant of the stress components in the disk subject to a normal concentrated force, and a characteristic dimension of the maximum size in the caustic curve was proposed to evaluate the contact force between the disks. Transient patterns of the caustic shadows were recorded by means of a high-speed camera of off-focus imaging, then the histories of the inter-contact forces among the disks were obtained with respect to the conditions of different masses and heights of the falling hammers. The influence of the impact loading and impulsive velocity was analyzed with respect to the force responses of the disk assembly, the double-peak phenomenon with comparison to the initial masses, and the energy dissipation of the systems under impact of different momentums.

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Experimental study on crack curving propagation in bending beams under impulsive load

Cited by 6 publications

References 4 publications

Fracture visualization using hybrid optical technique combining coherent gradient sensing (CGS) with caustics

Fracture visualization using hybrid optical technique combining coherent gradient sensing (CGS) with caustics

Influence of material orientation on crack tip stress singularity in orthotropic composites

Inter-contact force analysis of impacted disk assembly by dynamic caustics

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