Biocomposites reinforced with natural fibers: 2000–2010

Kenaf fiber reinforced composites: A review

The purpose of this review is to discuss the development and the state of the art in dynamic testing techniques and dynamic mechanical behaviour of rock materials. The review begins by briefly introducing the history of rock dynamics and explaining the significance of studying these issues. Loading techniques commonly used for both intermediate and high strain rate tests and measurement techniques for dynamic stress and deformation are critically assessed in Sects. 2 and 3. In Sect. 4, methods of dynamic testing and estimation to obtain stress–strain curves at high strain rate are summarized, followed by an in-depth description of various dynamic mechanical properties (e.g. uniaxial and triaxial compressive strength, tensile strength, shear strength and fracture toughness) and corresponding fracture behaviour. Some influencing rock structural features (i.e. microstructure, size and shape) and testing conditions (i.e. confining pressure, temperature and water saturation) are considered, ending with some popular semi-empirical rate-dependent equations for the enhancement of dynamic mechanical properties. Section 5 discusses physical mechanisms of strain rate effects. Section 6 describes phenomenological and mechanically based rate-dependent constitutive models established from the knowledge of the stress–strain behaviour and physical mechanisms. Section 7 presents dynamic fracture criteria for quasi-brittle materials. Finally, a brief summary and some aspects of prospective research are presented.

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A Review of Dynamic Experimental Techniques and Mechanical Behaviour of Rock Materials

A review on dynamic mechanical properties of natural fibre reinforced polymer composites

Machine tool spindle units

Free vibration characteristics of rotating Timoshenko beams

Vibration analysis of Timoshenko beam-columns on two-parameter elastic foundations

Vibration analysis of edge-cracked beams using a line-spring model

A novel impact three-point bend test method has been developed for determining the dynamic fracture-initiation toughness,K
Id, over the range of loading rates
 
$$10^5 MPa\sqrt m /s \leqslant K_I \leqslant 10^5 MPa\sqrt m /s$$

 . The split-Hopkinson pressure-bar technique is used to measure dynamic loads applied to a bend specimen with a fatigue precrack. The stress-intensity-factor histories for the bend specimen are evaluated by means of a dynamic finite-element technique and the standard formula (ASTM E 399-83) based on the measured dynamic loads. The time of crack initiation is determined using a strain gage mounted near a crack tip. The results for 7075-T6 aluminum alloy and Ti−6A1−2Sn−4Zr−6Mo alloy indicate that the reliableK
Id data can only be obtained by evaluation procedures which take the inertial effects into account. It is shown that the novel impact bend test method in conjunction with dynamic finite-element analysis provides an effective means of characterizing the dynamic fracture-toughness parameterK
Id.

A novel impact three-point bend test method for determining dynamic fracture-initiation toughness

The tensile strength and energy absorption of adhesive butt joints at high rates of loading are determined with a tensile split Hopkinson bar using a cylindrical specimen. A commercially available single-component cyanoacrylate adhesive (instantaneous adhesive) and two different adherend materials are used in the adhesion tests. The impact tensile strength of the cyanoacrylate adhesive butt joints is determined from the applied tensile stress history at failure initiation. The impact absorbed energy is obtained by numerical integration of dynamic tensile load-adhesive deformation data. Comparative tension tests at low and intermediate rates of loading are performed on an Instron testing machine. An axisymmetric finite element analysis is carried out to investigate the stress distributions in the adhesive layer of the cyanoacrylate adhesive butt joints. The effects of loading rate, adherend material and adhesive layer thickness on the tensile strength and energy absorption of the cyanoacrylate adhesive but...

Takashi Yokoyama

Papers

Free vibration characteristics of rotating Timoshenko beams

Vibration analysis of Timoshenko beam-columns on two-parameter elastic foundations

Vibration analysis of edge-cracked beams using a line-spring model

A novel impact three-point bend test method for determining dynamic fracture-initiation toughness

Experimental determination of impact tensile properties of adhesive butt joints with the split Hopkinson bar