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Tension Specimens (tension + specimen)

Distribution by Scientific Domains
Polymers and Materials Science100%

Kinds of Tension Specimens

  • compact tension specimen
    		•

    Selected Abstracts

    Influence of Ramberg,Osgood fitting on the determination of plastic displacement rates in creep crack growth testing

    FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 4 2007
    NAM-SU HUH
    ABSTRACT This paper investigates the effect of the Ramberg,Osgood (R-O) fitting procedures on plastic displacement rate estimates in creep crack growth testing, via detailed two-dimensional and three-dimensional finite-element analyses of the standard compact tension specimen. Four different R-O fitting procedures are considered: (i) fitting the entire true stress,strain data up to the ultimate tensile strength, (ii) fitting the true stress,strain data from 0.1% strain to 0.8 of the true ultimate strain, (iii) fitting the true stress,strain data only up to 5% strain and (iv) fitting the engineering stress,strain data. It is found that the first two fitting procedures can produce significant errors in plastic displacement rate estimates. The last two procedures, on the other hand, provide reasonably accurate plastic displacement rates and thus should be recommended in creep crack growth testing. Several advantages of fitting the engineering stress,strain data over fitting the true stress,strain data only up to 5% strain are discussed. [source]

    The evolution of the stress,strain fields near a fatigue crack tip and plasticity-induced crack closure revisited

    FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 1 2004
    L. G. ZHAO
    ABSTRACT The evolution of the stress,strain fields near a stationary crack tip under cyclic loading at selected R -ratios has been studied in a detailed elastic,plastic finite element analysis. The material behaviour was described by a full constitutive model of cyclic plasticity with both kinematic and isotropic hardening variables. Whilst the stress/strain range remains mostly constant during the cyclic loading and scales with the external load range, progressive accumulation of tensile strain occurs, particularly at high R -ratios. These results may be of significance for the characterization of crack growth, particularly near the fatigue threshold. Elastic,plastic finite element simulations of advancing fatigue cracks were carried out under plane-stress, plane-strain and generalized plane-strain conditions in a compact tension specimen. Physical contact of the crack flanks was observed in plane stress but not in the plane-strain and generalized plane-strain conditions. The lack of crack closure in plane strain was found to be independent of the material studied. Significant crack closure was observed under plane-stress conditions, where a displacement method was used to obtain the actual stress intensity variation during a loading cycle in the presence of crack closure. The results reveal no direct correlation between the attenuation in the stress intensity factor range estimated by the conventional compliance method and that determined by the displacement method. This finding seems to cast some doubts on the validity of the current practice in crack-closure measurement, and indeed on the role of plasticity-induced crack closure in the reduction of the applied stress intensity factor range. [source]

    Crack Propagation in Tool Steel X38CrMoV5 (AISI H11) in SET Specimens,

    ADVANCED ENGINEERING MATERIALS, Issue 9 2009
    Masood Shah
    An approach is proposed for the evaluation of surface fatigue damage of hot forming tools that undergo severe thermo mechanical loading. Fatigue crack propagation in a hot work tool steel X38CrMoV5-47HRC is investigated using single-edge cracked tension specimens with 3 different thicknesses (2.5, 1, 0.6,mm) and two R-values. [source]

    Fracture behaviour of maraging steel tensile specimens and pressurized cylindrical vessels

    FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 3 2004
    T. CHRISTOPHER
    ABSTRACT A three-parameter fracture criterion is applied for the development of a failure assessment diagram to maraging steels and its validity verified by considering the maraging steel fracture data of surface crack tension specimens (SCT) and pressure vessels having axial surface cracks. Fracture-strength/failure-pressure estimates based on this criterion are found to be in reasonably good agreement with test results. [source]

    Fatigue crack nucleation and growth in filled natural rubber

    FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 9 2003
    W. V. MARS
    ABSTRACT Rubber components subjected to fluctuating loads often fail due to nucleation and the growth of defects or cracks. The prevention of such failures depends upon an understanding of the mechanics underlying the failure process. This investigation explores the nucleation and growth of cracks in filled natural rubber. Both fatigue macro-crack nucleation as well as fatigue crack growth experiments were conducted using simple tension and planar tension specimens, respectively. Crack nucleation as well as crack growth life prediction analysis approaches were used to correlate the experimental data. Several aspects of the fatigue process, such as failure mode and the effects of R ratio (minimum strain) on fatigue life, are also discussed. It is shown that a small positive R ratio can have a significant beneficial effect on fatigue life and crack growth rate, particularly at low strain range. [source]

    Influence of anisotropy on a limit load of weld strength overmatched middle cracked tension specimens

    FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 5 2003
    S. ALEXANDROV
    ABSTRACT A plane-strain upper bound limit load solution for weld strength overmatched middle cracked tension specimens (M(T) specimens), is found. It is assumed that the weld material is isotropic, but the base material is orthotropic and its axes of orthotropy are straight and parallel to the axes of symmetry of the specimen. A quadratic orthotropic yield criterion is adopted. The solution is based on a simple discontinuous kinematically admissible velocity field and is an extension of the corresponding solution for the specimen made of isotropic materials. These two solutions are compared to demonstrate the influence of anisotropy on the magnitude of the limit load. [source]

    Evaluating the linear normalization technique for deriving J -resistance curves

    FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 2 2003
    J. R. TARPANI
    ABSTRACT In this paper, results from the linear normalization (LN) technique of Reese and Schwalbe for deriving J- crack resistance (J,R) curves have been compared, related to J,,a (J -integral,ductile crack growth) data points, to those obtained from traditional elastic compliance technique. Research results regarding a nuclear grade steel exhibiting a wide range of elastic,plastic fracture resistance agree quite well for both techniques until a certain level of toughness of the material. Below this critical level, LN produces inconsistent results for the sub-sized compact tension specimens (0.4T C[T]). The evidence suggests that the loss of applicability of the LN technique can be determined on the basis of the , plastic factor (,pl) for the best linear correlation achieved for ,PN,,a (normalised load gradient,ductile crack growth) data. [source]

    Ductile fracture of commercial purity titanium at room temperature

    FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 10 2000
    G. Shatil
    An experimental and numerical program was carried out to examine and assess the deformation and fracture behaviour of alloys of commercial purity (CP) titanium. The material rate-dependent deformation under constant displacement rates and under sustained loads was directly simulated in finite element analyses using an implemented unified material model. The simulations predicted the fracture of compact tension specimens subjected to J,R tests and sustained load tests employing a dimensional analysis and strain-hardening approach. Differences between two batches with different oxygen contents were examined and the limitation of the material model was investigated. [source]

    Subcritical Crack Growth in Lead Zirconate Titanate

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2004
    William S. Oates
    Subcritical crack growth in terms of velocity,stress intensity factor (v,K) curves in lead zirconate titanate (PZT) were experimentally characterized on poled and unpoled compact tension specimens. The poled specimens were tested under open- and short-circuit electrical boundary conditions, which resulted in an increase in fracture toughness by 0.2 MPa·m1/2 for the accessible velocity range (v= 10,9 to 10,4 m/s) in the open-circuit case. Subcritical crack growth of unpoled specimens was obtained under ambient (relative humidity = 35%) and dry (relative humidity , 0.02%) conditions over a regime in stress intensity factor of 0.5 MPa·m1/2. [source]

    Combined effect of temperature and thickness on work of fracture parameters of unplasticized PVC film

    POLYMER ENGINEERING & SCIENCE, Issue 3 2002
    A. Arkhireyeva
    The combined effect of temperature and thickness on the essential work of fracture (EWF) parameters for an unplasticized poly(vinyl chloride) (uPVC) film was investigated using double edge notched tension specimens. It was found that for the range of temperatures (23°C to 60°C) and thicknesses (0.15 mm to 0.40 mm) studied here, specific essential work of fracture (we) was independent of temperature at each thickness but increased with thickness at each temperature. It was found that at each temperature, we and its yielding (we,y) and necking/tearing components (we,nt), all increased linearly with increasing thickness. However, whilet we showed no significant variation with respect to temperature, its yielding component (we,y) decreased and its necking/tearing component increased (we,nt) with increasing temperature. It was found that estimated values of we and its components we,y and we,nt via crack opening displacement values were by and large unsatisfactory, being either much higher or lower than the directly measured values. [source]