This study presents two alternative methods to determine the cohesive law of bovine cortical bone under mode II loading, employing the End Notched Flexure (ENF) test. The direct method results from the combination of the progress of the mode II strain energy release rate with the crack tip shear displacement, obtained by digital image correlation. The resulting cohesive law is determined by differentiation of this relation relatively to the crack shear displacement. The inverse method employs finite element analyses with cohesive zone modelling, in association with an optimization procedure. The resulting strategy enables determining the cohesive law without establishing a pre-defined shape. The significant conclusion that comes out of this work is that both methods offer consistent results regarding the estimation of the cohesive law in bone. Given that the inverse method dispenses the use of sophisticated equipment to obtain the cohesive law in bone, it can be used as a more convenient procedure to accomplish efficient studies in the context of bone fracture characterization under mode II loading.

The prediction of the fracture behaviour through reliable and practical criteria in the design of structural timber elements and connections has become of great importance and demands a proper fracture characterization of the material. Eucalyptus globulus Labill is envisioned as a hardwood species with great potential for high performance structural purposes because of its major mechanical and durability properties, being so far mainly used in paper industry. Experimental research on the identification of the resistance curves to derive the critical strain energy release rate in Eucalyptus globulus L. under pure mode I and RL crack propagation system is performed by means of Double Cantilever Beam tests. Three different data reduction schemes are compared: the Modified Experimental Compliance Method; and two approaches of the Compliance Based Beam Method. These methods take into account the non negligible damage mechanisms at the fracture process zone and have the advantage of being based exclusively on the specimen compliance following an equivalent crack concept, for which crack length monitoring during testing is not required. The Compliance Based Beam Method turns out to be the most appropriate data reduction scheme to obtain the critical energy release rate in eucalyptus because of its simplicity. Concerning this, a high average value of 720�J/m2 was obtained confirming Eucalyptus globulus L. as a promising hardwood species for timber structural design.

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Fruits may be exposed to several unfavorable mechanical, climatic, and biological factors during ripening. Harvest and storage also challenge fruit integrity before fruits reach the consumer. In order to preserve fruit properties/characteristics it is essential that the structural and chemical integrity of the cuticle is maintained throughout fruit development and expansion. In addition, cuticles serve as protection against multiple biotic and abiotic stress factors and primarily act as a barrier to prevent water loss. Despite the important functions attributed to the cuticle, little is known about fruit cuticle biosynthesis and assembly, which is highly relevant when coping with adverse conditions. Presently, drought and heat pose severe constraints to the fruit industry via penalties in yield and fruit quality. Available climate change models suggest a scenario in which the impact of these environmental factors will negatively affect the fruit industry. A comprehensive understanding of the physiological and biochemical effects of limited water availability on fruit traits is a prerequisite for implementing breeding and knowledge-based strategies that enhance fruit crop tolerance to limited water availability. To address some of these questions, this chapter aimed to revise the existing information on cuticle physiology, composition, structure, and properties, also considering its impact on fruit under abiotic stresses, with an emphasis on water deficit. We also address the recent molecular progress in cuticle biosynthesis pathways and highlight some of the major research questions that will have to be dealt with in the future.

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The non-linear shear behaviour of bovine cortical bone is measured by coupling the Arcan test with digital image correlation. The experimental study is carried out on specimens taken from bovine femur and oriented along the longitudinal-tangential material plane. An ad hoc Arcan fixture is built to transfer the cross-head displacement of the testing machine into a shear loading at the centre of the V-notched section. A validation of predominant shear behaviour at the gauge section is shown from full-field deformation measurements. Moreover, direct evaluation of the shear modulus is obtained by integrating the shear strain component along the V-notches, avoiding numerical correction factors required in the classical data reduction scheme. The shear modulus of bovine cortical bone is found in good agreement with references from literature. Moreover, the shear stress at maximum load is understood as a suitable estimation of the shear strength. Furthermore, the Ramberg�Osgood model is found to provide an accurate description of the non-linear shear behaviour of bone tissue.

Earthquakes, soil settlements, traffic vibrations, and air pollution are some of the actions that can affect historic old buildings. Besides these, the lack of continuous maintenance puts a large part of this heritage in risk due to structural problems that reduce their own safety and that of their users. The preservation and risk mitigation of built cultural heritage require the use of reliable tools in order to assess its state of conservation and to identify and prevent potential vulnerabilities. Having this in mind, it is not possible to carry out destructive tests in most historic old buildings, so it is preferable to opt for nondestructive tests (NDT) or alternative methodologies that allow the physical and mechanical characterization of materials and structure. In this chapter, a general view of NDT methods used in historic buildings to obtain the geometrical information, the damage mapping, the mechanical and physical characterization, and the petrographic analysis of stones is presented. An alternative methodology to physically and mechanically characterize the stone of historic buildings using NDT tests is also proposed. The chapter ends with a case study carried out in the St. Leonard’s Church, a Portuguese monument built in Atouguia da Baleia village in the 13th century, where the alternative methodology here presented was applied. The final results of this study show that the methodology proposed allows the obtention of stress-strain curves in a completely nondestructive way, based on the water absorption coefficient at low pressure.

This work addresses the reconstruction of strain gradient fields at the wood growth ring scale from full-field deformation measurements provided by digital image correlation. Moreover, the spatial distribution of the earlywood and latewood radial modulus of elasticity is assessed. Meso-scale tensile tests are carried out on Pinus pinaster Ait. wooden specimens oriented in the radial–tangential plane under quasi-static loading conditions. A parametric analysis of the two-dimensional digital image correlation extrinsic and intrinsic setting parameters is performed, in a balance between spatial resolution and resolution. It is shown that the parametric module is an effective way to quantitatively support the choice of digital image correlation parameters in the presence of the high deformation gradient fields generated by the structure–property relationships at the scale of observation. Under the assumption of a uniaxial tensile stress state, the spatial distribution of the radial elastic modulus across the growth rings is obtained. It is observed that the ratio of the radial modulus of elasticity between latewood and earlywood tissues can vary significantly as a function of the digital image correlation parameters. It is pointed out, however, that a convergence value can be systematically established. Effectively, earlywood and latewood stress–strain curves are obtained and elastic properties are determined assuming the converged digital image correlation setting parameters.