Mechanical complications in implant-supported fixed dental prostheses are often related to implant and prosthetic design. Although the current ISO 14801 provides a framework for the evaluation of dental implant mechanical reliability, strict adherence to it may be difficult to achieve due to the large number of test specimens which it requires as well as the fact that it does not offer any probabilistic reference for determining the endurance limit. In order to address these issues, a new software program called ProFatigue is presented as a potentially powerful tool to optimize fatigue testing of implant-supported prostheses. The present work provides a brief description of some concepts such as load, fatigue and stress-number of cycles to failure curves (S-N curves), before subsequently describing the current regulatory situation. After analyzing the two most recent versions of the ISO recommendation (from 2008 and 2016), some limitations inherent to the experimental methods which they propose are highlighted. Finally, the main advantages and instructions for the correct implementation of the ProFatigue free software are given. This software will contribute to improving the performance of fatigue testing in a more accurate and optimized way, helping researchers to gain a better understanding of the behavior of dental implants in this type of mechanical test.

The use of Rectangular Hollow Sections (RHS) as columns in steel construction includes important advantages like higher mechanical strength and fire resistance. However, the practical demountable bolted joints between beams and columns are not easy to execute, due to impossibility of access to the inner part of the tube. The use of threaded studs welded to the face of the tube and bolted to the beam by means of angle cleats is one of the cheaper and most efficient solutions to obtain beam–column joints with a semi-rigid behavior, as is usually sought in building structures. Nevertheless, it is important to point out that the stud-diameter and the stud-class selection may affect the mechanical properties of the welded parts of the joint. In this paper, 8MnSi7 (with a commercial designation K800) and 4.8 threaded studs were welded to RHS steel tubes and mechanical properties on the weld, the Heat Affected Zones (HAZ), and the base metal were obtained in two different ways: through a correlation with the Vickers hardness and by means of the Small Punch Test (SPT). A study of the microstructure and tensile tests on the threaded studs and in the columns was also carried out. The research involved different types of stud qualities, tube wall thicknesses, and stud diameters. The work presented in this paper proved that in most cases, the welded joint between these studs and the RHS steel tubes present a reasonable static behavior that fulfils the requirements for the beam–column joints under static loading.

The determination of plywood bonding quality by shear testing is one of the most commonly used and informative tests, alongside bending strength, to characterise this compound material. Two types of birch plywood were studied: indoor use (class 1), thickness 18 mm, urea-formaldehyde glue; and exposed outdoor use (class 3), thickness 15 mm, phenolic formaldehyde glue. The corresponding pre-treatments indicated in standards UNE-EN 314-1 and -2 were applied to each type. To test the suitability of the method, the technique of digital image correlation (DIC) was used to obtain information about the complex modes of fracture present in compound materials such as plywood. Assessing the results based on the statistical extreme value theory provided more reliable and robust information about the failure strength values for low failure probabilities. The results confirm that DIC can be used to determine the true distribution of the deformations during the fracture process and, therefore, it provides greater knowledge of the details of the failure process. Statistical evaluation of the experimental data obtained with DIC indicates that test results exceeding the time limit of 30 ± 10 s should be evaluated, contrary to the operating procedure in standard UNE-EN 314-1, which states that they are invalid.