Determination of the envelopes for mode-mixity evaluation of adhesively bonded steel

This study is about the effect of the adhesive thickness and adhesive ductility on the mixed mode loading of DoubleCantilever Beam joints.The project is divided into three main tasks. The first task is about the development of a finite element model using acohesive zone model to design an experimental device based on the standard ASTM D6671D.The second task is concerned with the generation of experimental results in mixed mode varying the type of adhesiveand the adhesive thickness. In the third task, the experimental results will be used to develop an adhesive toughnessmodel as a function of the mode mixity.A dual actuator load frame from Virginia Techs Engineering Science & Mechanics Dept. was used to obtain theenvelopes for mode mixity for three different adhesives and thicknesses.A proposal for a data reduction scheme for the determination of the strain energy release rate is presented and validatedin this paper without the need of the experimental measure of the crack length

Mixed-Mode I + II fracture characterization of bonded joints using a novel Multi-Mode Apparatus

The present work presents the experimental test results to assess the toughness of an adhesive joint, using a previouslydefined crack equivalent data reduction scheme applied to a new multi-mode apparatus, inspired in a load jig previouslydeveloped by Fernlund and Spelt. The patented jig allows for easy alteration of the mode-mixity and permits coveringthe full range of mixed-mode I+II combinations. A data reduction scheme based on specimen compliance, beam theoryand crack equivalent concept is used to overcome several difficulties inherent to the test analysis. The method assumesthat the performed test can be viewed as a combination of the double cantilever beam and asymmetrically loaded endnotchedflexure tests, which provide modes I and II fracture characterization, respectively. A numerical analysisincluding a cohesive mixed-mode I+II damage model was performed considering different mixed-mode loadingconditions to validate the proposed data reduction scheme. Issues regarding self-similar crack growth and fractureprocess zone development are discussed. It was verified that the considered in-plane mix mode fracture criterion is wellcaptured using the proposed data reduction scheme

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Feasibility of the extended finite element method for the simulation of composite bonded joints

Adhesive-bonding for the unions in multi-component structures is gaining momentum over welding, riveting and fastening. It is vital for the design of bonded structures the availability of accurate damage models, to minimize design costs and time to market. Cohesive Zone Models (CZM’s) have been used for fracture prediction in structures. The eXtended Finite Element Method (XFEM) is a recent improvement of the Finite Element Method (FEM) that relies on traction-separation laws similar to those of CZM’s but it allows the growth of discontinuities within bulk solids along an arbitrary path, by enriching degrees of freedom. This work proposes and validates a damage law to model crack propagation in a thin layer of a structural epoxy adhesive using the XFEM. The fracture toughness in pure mode I (GIc) and tensile cohesive strength (sn0) were defined by Double-Cantilever Beam (DCB) and bulk tensile tests, respectively, which permitted to build the damage law. The XFEM simulations of the DCB tests accurately matched the experimental load-displacement (P-d) curves, which validated the analysis procedure

Influence of the cohesive law parameters on the strength prediction of adhesively-bonded joints

Adhesive joints are largely employed nowadays as a fast and effective joining process. The respective techniques for strength prediction have also improved over the years. Cohesive Zone Models (CZM’s) coupled to Finite Element Method (FEM) analyses surpass the limitations of stress and fracture criteria and allow modelling damage. CZM’s require the energy release rates in tension (Gn) and shear (Gs) and respective fracture energies in tension (Gnc) and shear (Gsc). Additionally, the cohesive strengths (tn0 for tension and ts0 for shear) must also be defined. In this work, the influence of the CZM parameters of a triangular CZM used to model a thin adhesive layer is studied, to estimate their effect on the predictions. Some conclusions were drawn for the accuracy of the simulation results by variations of each one of these parameters

Projeto conceitual de componentes de um forno industrial por meio da integração entre a engenharia reversa e o DFMA Conceptual design of components of an industrial oven through the integration between the reverse engineering and DFMA

O tema deste artigo é o estudo da integração da engenharia reversa (ER) e o projeto para manufatura e montagem (DFMA) como ferramentas de suporte ao projeto conceitual de produtos. A partir de uma fundamentação teórica sobre esses conceitos, o presente trabalho visa analisar a adequação de um modelo para a utilização integrada do DFMA com a prototipagem rápida em uma abordagem de ER no projeto de um novo sistema de fechadura para forno industrial e recomendar melhorias no projeto conceitual do novo sistema de fechadura. O método de pesquisa empregado foi a pesquisa-ação, uma vez que o pesquisador buscava resolver um problema identificado dentro do objeto de estudo em parceria com a equipe de profissionais da empresa. Os resultados das recomendações para o projeto conceitual apresentam redução, especialmente, no custo, no tempo para fabricação e no tempo para montagem. Conclui-se que o modelo de integração estudado foi adequado para apoiar o processo de projeto do sistema de fechadura proposto por meio da ER.<br>This study focuses on investigating the integration between reverse engineering (RE) and design for manufacture and assembly (DFMA) as tools to support the conceptual design of products. From a literature review of these concepts, this research aims to examine the adequacy of a model for the integrated use of DFMA and rapid prototyping in an ER approach in the design of a new locking system for an industrial oven and recommend improvements in conceptual design of a new lock system. The research method employed was action-research since the aim was to solve a problem identified in the company, object of study, in partnership with the company team. The results of the conceptual design indicate reductions, especially in cost, time to manufacture, and assembly time. It was concluded that the integration model studied was adequate to support the design process of the locking system proposed by the ER approach