Reduction of Die Wear and Structural Defects of Railway Screw Spike Heads Estimated by FEM

Railway spike screws are manufactured by hot forging on a massive scale, due to each kilometer of railway track needing 8600 spike screws. These components have a low market value, so the head must be formed in a single die stroke. The service life of the dies is directly related to the amount of energy required to form a single screw. The existing standard for spike screws specifies only the required tolerances for the head dimensions, particularly the angle of the hub faces and the radius of agreement of the hub with the cap. Both geometrical variables of the head and process conditions (as-received material diameter and flash thickness) are critical parameters in spike production. This work focuses on minimizing the energy required for forming the head of a railway spike screw by computational simulation. The variables with the highest degree of incidence on the energy, forging load, and filling of the die are ordered statistically. The results show that flash thickness is the variable with the most significant influence on forming energy and forming load, as well as on die filling. Specifically, the minimum forming energy was obtained for combining of a hub wall angle of 1.3° an as-received material diameter of 23.54 mm and a flash thickness of 2.25 mm. Flash thickness generates a lack of filling at the top vertices of the hub, although this defect does not affect the functionality of the part or its serviceability. Finally, the wear is mainly concentrated on the die splice radii, where the highest contact pressure is concentrated according to the computational simulation results.This work is supported by the Serra Húnter program (Generalitat de Catalunya) reference number (UPC-LE-304 (2018)) and by the Aeronautics Advanced Manufacturing Center (CFAA). Thanks also are given to special agreement INTI-Faculty of engineering of Bilbao and to university group grant IT 1337-19

Reduction of die wear and structural defects of railway screw spike head estimated by FEM

Railway spike screws are manufactured by hot forging on a massive scale, due to each kilometer of railway track needing 8600 spike screws. These components have a low market value, so the head must be formed in a single die stroke. The service life of the dies is directly related to the amount of energy required to form a single screw. The existing standard for spike screws specifies only the required tolerances for the head dimensions, particularly the angle of the hub faces and the radius of agreement of the hub with the cap. Both geometrical variables of the head and process conditions (as-received material diameter and flash thickness) are critical parameters in spike production. This work focuses on minimizing the energy required for forming the head of a railway spike screw by computational simulation. The variables with the highest degree of incidence on the energy, forging load, and filling of the die are ordered statistically. The results show that flash thickness is the variable with the most significant influence on forming energy and forming load, as well as on die filling. Specifically, the minimum forming energy was obtained for combining of a hub wall angle of 1.3¿an as-received material diameter of 23.54 mm and a flash thickness of 2.25 mm. Flash thickness generates a lack of filling at the top vertices of the hub, although this defect does not affect the functionality of the part or its serviceability. Finally, the wear is mainly concentrated on the die splice radii, where the highest contact pressure is concentrated according to the computational simulation results.Peer ReviewedPostprint (published version

Reduction of Die Wear and Structural Defects of Railway Screw Spike Heads Estimated by FEM

Railway spike screws are manufactured by hot forging on a massive scale, due to each kilometer of railway track needing 8600 spike screws. These components have a low market value, so the head must be formed in a single die stroke. The service life of the dies is directly related to the amount of energy required to form a single screw. The existing standard for spike screws specifies only the required tolerances for the head dimensions, particularly the angle of the hub faces and the radius of agreement of the hub with the cap. Both geometrical variables of the head and process conditions (as-received material diameter and flash thickness) are critical parameters in spike production. This work focuses on minimizing the energy required for forming the head of a railway spike screw by computational simulation. The variables with the highest degree of incidence on the energy, forging load, and filling of the die are ordered statistically. The results show that flash thickness is the variable with the most significant influence on forming energy and forming load, as well as on die filling. Specifically, the minimum forming energy was obtained for combining of a hub wall angle of 1.3° an as-received material diameter of 23.54 mm and a flash thickness of 2.25 mm. Flash thickness generates a lack of filling at the top vertices of the hub, although this defect does not affect the functionality of the part or its serviceability. Finally, the wear is mainly concentrated on the die splice radii, where the highest contact pressure is concentrated according to the computational simulation results

Dossier 1st EdTech Winter School “Emerging trends and new horizons in the study of education and technology”

There is a need to raise the professional standards of those who promote, implement and monitor innovation in public digital education. That means to increase (both nationally and regionally) technical capacities as well as to diversify the opportunities for collaboration and exchange within those communities that can generate better learning conditions (Caprile, Palmén, Sanz, Dente, 2015).These are some of the main concerns that led to the creation of the Center for Research Fundación Ceibal, which in partnership with the National Research and Innovation Agency (Agencia Nacional de Investigación e Innovación [ANII]) and with the support of all the universities in the country, organized a global summit between academics and policymakers in Uruguay (also known as Winter School). The goal of this international meeting, which took place in Punta del Este in 2017, was to analyze and discuss cross-cutting topics at the intersection of educational, ICT research and policy with leading international experts in the field.One of the outcomes of this multi-national collaboration was the publication of this special edition, which addresses some of the critical topics to be considered when designing, implementing and evaluating the quality and cost-effectiveness of different education and technology programs. This research was conducted by academics and experts from universities and partner institutions from Australia, Mexico, Argentina, Chile, Spain, Israel, and Uruguay. Adopting different perspectives and approaches, the authors successfully explored how these digital education policies can have a positive impact on the learning processes. Other questions they posed were: how can technological interventions with a real positive impact be designed and implemented? How can the region learn from failures? What lessons can we learn from successful experiences and good practices from other countries? What role does the social and cultural context play in the technology and education equation? Which new languages and pedagogies are worth considering? What are the opportunities and challenges to be considered?As Megan Erikson argues, 'education is not a design problem with a technical solution', so the fundamental questions of what works, and under what circumstances are more relevant than ever. These, among others, are critical questions to better understand the affordances and constraints of technology in the world of education. Highly grateful for the global collaboration which supported the elaboration of all these articles you shall find here, we invite you to enjoy a good read and pose new questions that help us rethink learning and equity in a society that is changing and becoming globalized at an unprecedented (and sometimes disturbing) speed.Fundación Ceibal - Universidad Católica del Urugua