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In this study, a novel method for determining stresses in the torsion problems of laminated composite trimetallic and bimetallic bars was developed and evaluated via experimental and numerical analyses. The objective of this method is to transform a real transversal section of a model for a laminated composite bar into a hypothetical virtual section that is homogenous and isotropic. An analogy with the transformed-section method for solving composite beams under flexion was conducted. The shear stresses (maximum on external surfaces and interfaces) in laminated composite bars were undergoing torsion. Isotropic symmetric and asymmetric laminated composite bars were examined analytically, and the results of their respective experimental and numerical tests were analyzed. The proposed method exhibits differences between 2 % and 12 % compared with the experimental results and between 2 % and 10 % compared with the results obtained using the finite element method.

Cuando un elemento estructural es fabricado con un material compuesto laminado (MCL) y se somete a cambios de temperatura, se generan esfuerzos termicos intralaminares. Los esfuerzos termicos intralaminares se presentan debido a las diferencias en los coeficientes de expansion termica y a las propiedades elasticas de las capas que componen al MCL. Es posible que una combinacion de esfuerzos intralaminares y esfuerzos mecanicos puedan producir fallas por separacion en las capas de los MCL (delaminacion). En este articulo se presenta un modelo analitico con el cual se calculan esfuerzos termicos globales e intralaminares producidos por cambios de temperatura inducidos en MCL metalicos, simetricos y sin restricciones en las fronteras. El modelo es alimentado por datos de deformacion obtenidos por galgas extensometricas colocadas en la frontera del MCL. El modelo puede ser utilizado en la determinacion de esfuerzos intralaminares y globales considerando restricciones o cargas en la frontera, solo si el problema es de esfuerzos planos. El modelo fue desarrollado haciendo una analogia al modelo analitico desarrollado en [1], el cual consiste en calcular esfuerzos intralaminares y globales que se generan por la diferencia entre las constantes elasticas de los materiales que componen un MCL sometido a tension simple. El modelo propuesto se fundamenta en la teoria de la elasticidad lineal, en la teoria clasica de laminas y en el principio de superposicion. Con el modelo y mediante un arreglo de pruebas experimentales, se pueden calcular los coeficientes de expansion termica (CET) de cada una de las capas. Finalmente, se realizaron pruebas experimentales de validacion las cuales mostraron que el modelo propuesto es confiable y consistente. Palabras clave: Esfuerzo Termico, Esfuerzo Intralaminar, Coeficiente de Expansion Termica, Materiales Compuestos.

This paper presents Acosta’s (Acosta et al., 2016) constitutive analytical model, which is used for the mechanical analysis of intralaminar and global stresses in symmetrical laminated composite materials subject to axial load. The model is composed of both a laminated constitutive model and a constitutive model for each layer. The model and its method of analysis were used to obtain the elastic properties of the core of a symmetric metal sandwich plate and the properties of a non-symmetric bimetallic material. The model is fed with information from strain gages, which register deformations at the boundary of the compounds analyzed under axial load. The results obtained showed that the proposed method is simple and reliable. Keywords: Elastic properties, Laminated compounds, Sandwich material, Intralaminar stress

Background and Purpose: The challenges imposed by today’s societies, which demand products and services of quality and of greater technological complexity, require the formation of highly trained human resources, which confront the various problems that arise in industries. Reverse engineering and the direct design are applied to solve problems in companies and universities. These methods, in combination with active methodologies, provide tools that potentiate the teaching of engineering. This article presents a proposal for the definition of reverse engineering and its application, together with the direct design method, in the development of novel procedures oriented toward the teaching of engineering.

In the present chapter, we have developed mathematical modeling and analysis by finite element (FEA) process of turning with chip detachment; the study incorporated the dynamic and structural cutting orthogonal and oblique mathematical models in three dimensions (3D) and with incorporating thermal mesh structural static fluid for your simulation in FEA software. Validation is performed on an experimental basis by record temperatures and mediated the release of chip in the process of turning with octagonal and oblique cut. With the simulation are determined variables important to optimize; these are orthogonal and oblique cutting: cutting speed, cutting depth, and angle cutting, presenting a variation of 4–8% with respect to the experimental values. In this process, it was determined that cutting temperature presents a value means of 132 °C and a maximum of 147 °C and a minimum of 115–14 °C cutting angle and a forward speed of a 0.1466 speed m/s temperature-optimized cutting. In the process of chip detachment are decisive values for temperature, speed, depth, and angle of cut according to a previous simulation incorporating the models mentioned above.