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Image correlation is becoming a popular full field optical experimental technique in wide range of applications because it is cheap, fast and easy. It performs equally well at the micro and the macro scales and requires minimal surface preparation. In this work the 2D image correlation technique was used to measure the in-plane displacement fields near the crack tip. Commercial image correlation software DaVis 6.0 by LaVision was employed.

Failure of blades of a turbo-compressor occurred during operation. Three different typical failure geometries were observed repeatedly. One mode was clearly identifiable as the first bending mode. The other two (Figs. 1–2) could not be directly identified.

The method of caustics introduced by Manogg [ 1 ] and developed further by Theocaris [ 2 ] is nowadays considered as a very useful and flexible tool for the investigation of the stress concentration and the stress intensity factors for the case of structures with geometrical discontinuities. However, a number of questions regarding the range of validity of the method remain unanswered, in spite of the intensive research carried out. The most crucial points are related to the influence of the plastic zones developed in the immediate vicinity of the singular points [ 3 ], to the triaxiality [ 4 , 5 ] and to the size of the discontinuities especially in the case of holes [ 6 ].

Fracture toughness testing of ductile materials can be difficult in situations where it is not possible to measure crack extension during the test, such as under high rate loading or in aggressive environments. In these situations, an alternative method of inferring crack extension must be used to generate the tearing resistance curve, and thereby determine ductile crack initiation. ASTM test method E1820-01 uses the Normalization method to generate the plasticity function for the specimen, which can then be used to calculate crack extension. This method relies heavily on accurate measurement of the load, displacement and crack length at the end of test. These measurements are used to generate a point on the normalized load-displacement plot, known as the “anchor point”. If a test ends with unstable crack extension, the anchor point cannot be determined and the method cannot be applied. If there is a large amount of crack extension in a test, the uncertainty in the derived plasticity function increases, which can lead to non-conservative J-R curves. An alternative approach that can be used to reduce the dependency on the anchor point is the Compliance Ratio (CR) method. This method uses a quasi-static test with unloading compliance to generate a load-displacement record with no crack extension, or “key curve”. Once this key curve is obtained, it can be scaled to account for the effect of loading rate. The specimen compliance at any point in a dynamic test record is determined by comparing the key curve with the actual load at the same displacement, and from this the crack extension can be determined. There are problems with this approach when the quasi-static key curve does not match the dynamic test record early in the test where blunting transitions to ductile tearing.

An experimental study is presented here related to the behaviour of U-notched prismatic Dionysos marble specimens subjected to either three- or four-point bending or to direct tension, in an effort to investigate the variation of the Crack Opening Displacement (COD) versus the externally applied load. The purpose of the study is the determination of an-easy-to-use and reliable tool that could serve as fracture criterion in the hands of engineers working for the restoration projects of various ancient monuments as well as in every day’s practical applications.

Due to environmental and healthy concern, the allowable usage of lead will be decreased. The search of new lead-free solders with equivalent mechanical properties and microstructural stability to eutectic tin-lead (Sn-Pb) solder is an ongoing task. Solder joints in electronic products play not only a role to interconnect the electronic components but also to ensure the structural reliability of the electronic packages. As service temperatures for electronic assemblies are usually located in the high homologous temperature ranges (> 0.5T_m) of solder alloys, creep damage may take place. Therefore, a thorough understanding of the creep behavior of the newly developed lead-free solders is of extreme importance to the designers of electronic assemblies.

Contrary to the quasi-static case, where adjustable rollers used as supports reduce effect of friction significantly, the fixed supports are usually used in dynamic tests. Thus, there is always some friction in the specimen/support contact zones during an impact test. In the literature related to the numerical modelling of an impact fracture test, the problem of friction between a specimen and anvil has not attracted much attention. From the very beginning of the impact test modelling it was clear that friction affects results of a test considerably (see Saxon et al. [ 1 ]). However, detailed quantitative analysis of friction caused changes in time variation of contact forces and dynamic stress intensity factor (DSIF) is still unavailable. In this work, some results of the finite element (FE) modelling of an impact test for a wide range of specimen configurations and values of coefficient of friction are presented.

Impact charateristics of simply-supported circular thin plates made of PC/ABS (50/50) blends having 10 wt% content of rubber with a rubber particle diameter of 270 nm called PA-1 and of 150–170 nm called PA-2 tested at room temperature by use of a drop weight impact apparatus under different speeds: 2, 3, and 4 m/sec has been studied. Features of the target were viewed to describe definite alteration of the plates induced by a hemispherical tip-ended cylindrical striker due to effect of rubber particle size distributed in the blends.

This paper deals with results of high-speed tensile tests on glass-fibre reinforced thermoplastic materials. Starting point of the investigations is the fact, that requirements for a modern material have been steadily increased. One reason here is the increasing use of computer-aided design over the past years. Especially for the automotive industry, not only the mechanical properties as results of quasi-static tests are of interest. According to EuroNCAP crash tests, strain rates up to 200 s^−1 can be observed in the region of crash boxes at 64 km/h initial speed (Fig. 1a) [ 1 , 2 ]. Therefore, it is necessary to perform dynamic tests with strain rates up to maximum values of 10^4–10^6 s^−1 [ 3 , 4 ]. For example, with commercially available servo-hydraulic testing machines strain rates between 10^−3 to 10^3 s^−1 can be realized (Fig. 1b).

Cracking of concrete due to corrosion is a very common pathology that can be observed on various structures. Corrosion is initiated by the penetration of chlorides or by the reactive transport of carbon dioxide in most cases. The consequences of corrosions are (i) the reduction of the resistive section of reinforcements (ii) the creation of expansive products (commonly denoted rust) (iii) the fragilization of steel and finally (iv) the cracking of concrete [ 1 – 4 ].