1,179 research outputs found
Carta a su esposa sobre la traición de Don Ramón Martínez Caro, 1836 septiembre 25
No full textSanta Anna informa a su esposa sobre la traición de Don Ramón Martínez Caro, a quien Don Tomás González le presentó antes de su partida; Santa Anna fue capturado más tarde con Martínez Caro. Descubrió que Martínez Caro le robó uno de los botones de brillantes de su camisa, que estuvo desaparecido durante días. Advierte a su esposa que no crea nada de lo que Martínez Caro pueda decir o hacer, ya que podría intentar aprovecharse de la difícil situación de Santa Anna y registrar su equipaje, así como el del difunto Castrillón, en busca de documentos valiosos. Santa Anna aconseja a su esposa que busque la ayuda del compadre Vásquez para garantizar la custodia segura del botón robado, que vale quinientos pesos. Santa Anna ha solicitado permiso al gobierno para enviar a alguien a informar a su esposa sobre la situación y para enviar su disposición testamentaria en caso de que no sobreviva a su situación actual. Termina la carta instando a su esposa a cuidar de sus hijos y a mantenerse bien, como lo desea su apasionado esposo. —— Santa Anna informs his wife about the betrayal of Don Ramón Martínez Caro, who Don Tomás González presented to him before his departure; Santa Anna and was later captured with Martínez Caro. He discovered that Martínez Caro stole one of his diamond buttons from his shirt, which was missing for days. He warns his wife not to believe anything Martínez Caro might say or do, as he may try to take advantage of Santa Anna's difficult situation and search his luggage, and that of the deceased Castrillón, for valuable documents. Santa Anna advises his wife to seek the help of compadre Vásquez to ensure the safekeeping of the stolen button, worth five hundred pesos. Santa Anna has requested permission from the government to send someone to inform his wife of the situation and to send his testamentary disposition in case he does not survive his current predicament. He ends the letter urging his wife to take care of their children and to remain well, as desired by her passionate husband. 1 f. (2 p.
Monseñor Caro y el apostolado familiar en Tarapacá (1911-1926)
No full textThe article analyzes the familiar apostolate of Jose Maria Caro in the Vicarship of Tarapaca between the years 1911 and 1926. In this analysis the author puts emphasis in José María’s job as a missionary and how through the practical Christianity he is able to design and implement an integral reform in the tarapaqueña family.El presente artículo analiza el apostolado familiar de José María Caro en el Vicariato Apostólico de Tarapacá entre los años 1911 y 1926. En este análisis la autora pone énfasis en su labor misional y cómo a través del cristianismo práctico diseña e implementa una reforma integral de la familia tarapaqueña
Petición pidiendo la aceptación de un testimonio y un vicario que vaya a Tenango para resolver un pleito, 1566 noviembre 12
No full textPetición a funcionarios reales (probablemente la Audiencia de México) pidiéndoles que acepten un testimonio y envíen un vicario. El autor afirma representar a los indígenas de Tenango, un pueblo y cabecera, en un pleito contra los indígenas que viven en Calayuco y otras estancias sujetas por no ir a misa en Tenango. —— Petition to royal officials (likely the Audiencia of Mexico) asking them to accept a testimony and send a vicar. The author claims to represent the Indigenous people of Tenango, a pueblo and regional seat, in a suit against the Indigenous living in Calayuco and other subject settlements for not going to church in Tenango. 1 f. (2 p.
Testing of composite stiffened panels made by resin infusion
No full textComposite sandwich structures often have complicated geometry that limits optical access, which prevents deployment of full field imaging techniques, such as Digital Imaging Correlation (DIC) and Thermoelastic Stress Analysis (TSA). During testing, it is difficult to use traditional inspection approaches to internal regions where debonds may occur in the interfaces between the face sheets and core material. Here, mirrors are utilised to allow optical access to face sheets of sandwich specimens loaded in bending, so that TSA can be employed to characterise interfacial debonding through the face sheets. To separate the surface thermoelastic response, ΔT, from that generated from the interfacial regions, DIC is used to obtain the surface strains. From this, ΔT from the surface in the vicinity of a debond is estimated. The interface ΔT is then obtained by subtracting it from ΔT obtained from TSA.
From this, the interfacial fracture process can be characterised.7227.mp4
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Caracterización de estados singulares de tensión en esquinas multimateriales. Aplicación a uniones adhesivas con materiales compuestos
No full textLa finalidad de la presente Tesis Doctoral es el análisis de las uniones adhesivas a solape entre materiales metálicos y materiales compuestos. De la amplia variedad de tipologías, tipos de adherentes y adhesivos, el presente trabajo se ha centrado en unas uniones que habitualmente se presentan en la fabricación y montaje de componentes del sector aeronáutico: un iones a solape de chapas finas de metal (generalmente aluminio) y laminados de material compuesto (generalmente preimpregnado de fibra de carbono) utilizando adhesivos tipo film (generalmente epoxy) con curado a temperatura. Esta tipología concreta de unión y materiales a unir restringen significativamente los modelos de análisis que pueden ser empleados y los mecanismos de fallos que pueden aparecer, asimismo permiten, como se expondrá más adelante, enfocar el problema utilizando un enfoque de tensiones singulares. Es preciso matizar que esta limitación tipológica no supone un ámbito reducido de aplicación, dado que los adhesivos desarrollan su máximo potencial en uniones de este tipo, no siendo tan ventajoso su uso en otro tipo de uniones, como por ejemplo en uniones a tope
Static and fatigue performance of non-circular rivet joints: Comparison between numerical modelling and preliminary testing
No full text© 2024 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC licenseAlternative non-circular rivet joint geometries are investigated. An optimum non-circular rivet
geometry based on a continuous change in the radius of curvature is proposed to minimise the
stress concentration factor on structural components joined by rivets, which is the first time to be
proposed to the best author’s knowledge. By-pass and bearing load cases are considered for both
numerical analysis and a preliminary experimental programme. For isotropic materials, linear
elastic analyses (for the stress concentration factors) and fully elastoplastic analyses are carried
out in the numerical simulations. The experimental programme includes static tests (for both by-
pass and bearing load cases) and fatigue tests (by-pass loading) for isotropic materials, whereas
only static tests (for both by-pass and bearing load cases) are considered for orthotropic com-
posites. The correlation of experimental and numerical results indicates that the reduction of the
stress concentration factor plays an important role in improving fatigue behaviour and has almost
no influence under static loading. Hence, the life of structural riveted components may increase,
improving the life cycle of the entire structure in service
Tensile and shear strength of bimaterial interfaces within composite materials
No full textThe determination of the tensile and shear strengths of homogeneous materials can be easily performed by standard tensile and shear (e.g. Iosipescu) tests. Nevertheless, when the determination of these strengths involves a bimaterial interface, the standard samples present bimaterial corner configurations at their free-edges which generate singular stress fields. In the presence of these singular stress fields, the tensile and shear stress distributions are strongly non-uniform at these edges, where failure initiates and propagates along the bimaterial interface. The apparent strength obtained from these tests is not representative of the regularized strength of the bimaterial interface. To eliminate the stress singularities, a small notch is made on one of the materials along the interface perimeter, in this study. This idea, originally proposed by Lauke and Barroso (Compos. Interface, 18:661-669, 2011) for ascertaining tensile strength, is now adapted to ascertain shear strength, using a modified geometry of the Iosipescu sample, and it has also been generalized to configurations involving composite materials. Both proposals, for the tensile and shear tests, are performed using the bimaterial configuration of a composite and an adhesive; a bimaterial interface which typically appears in adhesive joints with composites. The local notch geometry is defined using semi-analytical tools developed by the authors and numerically verified by Finite Element models. The modified bimaterial geometries, tested under tension, demonstrated a higher tensile strength. However, the modified bimaterial geometries tested in shear did not show any clear influence over the failure load with or without the notch in the particular bimaterial configuration tested in this study. © 2016 Elsevier Ltd
Notched-butt test for the determination of adhesion strength at bimaterial interfaces
No full textFor the experimental determination of adhesion strength between materials it is desirable to have a uniform stress distribution within the interface of the specimen. The common butt-test with a flat interface between two adhering materials produces stress singularities at the edges of the specimen but shows uniform stress distribution along the interface within the material. To avoid a premature failure at the edge due to the presence of the singular stress field, a notch can be machined at the interface within one of the materials. For isotropic materials, the notch geometry depends on the Dundurs parameters of the bimaterial system. This notch produces a certain local material angle and eliminates stress singularities at the specimen edges. Analytical and finite-element calculations provide the notch geometry appropriate for uniform stress distribution along the whole interface. The applicability of the test is proven by the determination of adhesion strength between polycarbonate and thermoplastic polyurethane. © 2012 Koninklijke Brill NV, Leiden
Computational semi-analytic code for stress singularity analysis
No full textProblems of stress singularities in single or multi-material corners have been addressed by many authors over the years. Most of the authors presented closed-form corner-eigenequations for special cases, and often there is no easy way to check if the solution is correct. In this work, we present a general computational tool that can solve many different cases of stress singularity problems for multi-material corners under generalized plane strain. The semi-analytic code is based on the matrix formalism presented in Mantič et al. (1997, 2014); Barroso et al. (2003); Herrera-Garrido et al. (2022) and is developed in MATLAB. The following boundary conditions are implemented: stress-free, fixed, some restricted or allowed direction of displacements (defined either in the reference frame aligned with the cylindrical coordinate system or in an inclined reference frame), or frictional sliding. The following interface condition between two consecutive materials are implemented: perfectly bonded, and frictionless or frictional sliding. The code can analyze both open and closed (periodic) corners, composed of one or multiple materials with isotropic, transversely isotropic or orthotropic (with any orientation) constitutive laws. The code has proven to be a reliable, very accurate, robust and easy-to-use tool, which has been verified by comparing the results computed with those obtained by other authors. A summary of the corner singularity problems solved is presented. The results of the corner singularity analysis obtained by the code can be further used for prediction of crack onset at the corner tip by the Coupled Criterion of Finite Fracture Mechanics and FEM, see García and Leguillon (2012) and references therein
A review on failure theories and simulation models for adhesive joints
No full textIn the framework of the Cost Action CERTBOND (Reliable roadmap for certification of bonded primary structures), a wide group of researchers from 27 European Countries have had the opportunity to work on the topic of certification of bonded joints for primary structural applications from different engineering sectors such as the aerospace, automotive, civil engineering, wind energy and marine sectors. Since virtual testing and optimization are basic tools in the certification process, one of the key objectives of CERTBOND is to critically review some of the available models and failure theories for adhesive joints. The present paper summarizes the outcome of this task. Nine different models/theories are described in detail. Specifically, reviewed are the Classical Analytical Methods, the Process Zone Methods, Linear Elastic Fracture Mechanics (LEFM), the Virtual Crack Closure Technique (VCCT), the Stress Singularity Approach, Finite Fracture Mechanics (FFM), the Cohesive Zone Method (CZM), the Progressive Damage Modeling method and the Probabilistic methods. Also, at the end of the paper, the modeling of temperature effects on adhesive joints have been addressed. For each model/theory, information on the methodology, the required input, the main results, the advantages and disadvantages and the applications are given
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