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A new titanium alloy improving the operation of implants additively manufactured and including laterally closed lattice structures is proposed. The new alloy possesses an increased affinity to the bone. The measured bone–interface implant (BII) of less than 10 mm and bone–implant contact (BIC) of 95% demonstrated an excellent osseointegration. Furthermore, since additive manufacturing naturally leads to a high-roughness surface finish, the wettability of the implant is increased. The combination of these factors is pushing ossification beyond its natural limits. In addition, the quality and speed of the ossification and osseointegration in/around laterally closed lattice implants open the possibility of bone spline key of prostheses. This enables the stabilization of the implant into the bone while keeping the possibility of punctual hooks allowing the implant to be removed more easily if required.
We discuss the non-linear stress–strain behavior of microcracked polycrystalline ceramics under uniaxial tension and compression (displacement control).
Micromechanics explanation and modeling of its basic features, such as non-linearity and hysteresis in stress–strain curves, are developed, with stable microcrack propagation and “roughness” of intergranular cracks playing critical roles in tension and crack sliding playing a critical role in compression. Experiments involving complex loading histories are explained, and themodel is shown to reproduce the basic features of the observed stress–strain curves.
Although concrete itself is not a combustible material, concrete mixtures with high density, such has high-performance concretes (HPCs), are susceptible to significant damage during fires due to explosive spalling. Past research has shown that the inclusion ofpolymer fibres in high density concrete can significantly mitigate this fire damage. The exact mechanisms causing this increased spalling resistance are not yet fully understood, but it is thought that the fibres facilitate moisture transport during fire exposure, which in turn contributes to relief of internal stresses in the spalling-susceptible region. In this study, X-ray Computed Tomography (CT) was applied to observe the interaction between polymer fibres and cracking during thermal exposure. For this purpose, two concrete samples containing different polymer fibre types were subjected to incremental application of a defined thermal exposure. CT images were acquired before and after each thermal exposure and powerful image processing tools were used to segment the various material components. This enabled a detailed analysis of crack formation and propagation as well as the visualization and quantification of polymer fibre characteristics within the concrete. The results demonstrated that the orientation of both fibres and cracks in polymerfibre reinforced concrete tend to be anisotropic. The results also indicated that crack geometry characteristics may be correlated with fibre orientation, with cracks tending to run parallel to fibre beds. Clear quantitative relationships were also observed between heating and increasing cracking levels, expressed in terms of both crack surface area and crack volume.
Although concrete itself is not a combustible material, concrete mixtures with high density, such has high-performance concretes (HPCs), are susceptible to significant damage during fires due to explosive spalling. Past research has shown that the inclusion of polymer fibres in high density concrete can significantly mitigate this fire damage. The exact mechanisms causing this increased spalling resistance are not yet fully under-stood, but it is thought that the fibres facilitate moisture transport during fire exposure, which in turn contributes to relief of internal stresses in the spalling-susceptible region. In this study, X-ray Computed Tomography (CT) was applied to observe the interaction between polymer fibres and cracking during thermal exposure. For this purpose, two concrete samples containing different polymer fibre types were subjected to incremental application of a defined thermal exposure. CT images were acquired before and after each thermal exposure and powerful image processing tools were used to segment the various material components. This enabled a detailed analysis of crack formation and propagation as well as the visualization and quantification of polymer fibre characteristics within the concrete. The results demonstrated that the orientation of both fibres and cracks in polymer-fibre reinforced concrete tend to be anisotropic. The results also indicated that crack geometry characteristics may be correlated with fibre orientation, with cracks tending to run parallel to fibre beds. Clear quantitative relationships were also observed between heating and increasing cracking levels, expressed in terms of both crack surface area and crack volume.