1,721,106 research outputs found
Un nuovo modello analitico per il comportamento elasto - plastico di giunzioni saldate per punti
No full textA new analytical model for the elastic-plastic behaviour of spot welded joints subjected to orthogonal load
No full textAn analytical procedure for the evaluation of the elastic-plastic stiffness behaviour of spot welded joints is presented. The procedure is based on a new model of spot weld region: a circular plate having variable thickness with a central rigid nugget, which is resolved using an original analytical method. The closed-form solution allows to describe the displacement of a rigid nugget when an axial orthogonal load is applied on the plate while plasticity and large deflections are present. The goal is to reach a reliable spot weld region model which can be used as the basis to develop a spot weld element in FE analysis even when plasticity and large deflections are in effect. The procedure is as completely original as no other can be found in the technical literature, and it has been applied to some examples of plates usually employed for spot weld analysis. The analytical results obtained by using the new general relations precisely match those obtained modelling spot weld area by FEA. (c) 2008 Elsevier Ltd. All rights reserved
Analytical characterization of plastic flow in spot welded joints
No full textAn analytical procedure for the evaluation of the elastic-plastic behaviour of spot welded joints, in terms of global stiffness is presented in this paper. The analytical procedure is based on a new reference theoretical model of the sheet region close to spot welded joint able to follow the evolution of plastic flow close to the joint. The new closed-form solutions allow to define the deflection of spot joint when an axial load is applied and plasticization occurred. The reference theoretical model is based on theory of elasticity and consists in a circular plate having two annular portions with different variable thickness and having a central rigid core representing the spot weld. This model allows to correctly simulate the actual plasticization radius when load increases and the global stiffness of the actual joint. The analytical procedure presented is new and lead to the definition of a spot weld finite element, able to precisely evaluate both local and overall stiffness of spot joints, also in elastic plastic field. This spot weld element lead to accurate simulation of multi spot welded structures with a very low computational effort
Influenza delle Condizioni di Vincolo sul Modello Analitico del Comportamento Elasto-Plastico di Strutture Saldate a Punti
No full textCaratterizzazione analitica del fronte di plasticizzazione in strutture saldate per punti
No full textCaratterizzazione numerica e sperimentale di friction stir spot welds in alluminio 6082-T6
No full textAnalysis of multi-bolt composite joints with a user-defined finite element for the evaluation of load distribution and secondary bending
No full textThe present paper aims to demonstrate the capabilities of the Composite Bolted Joint Element (CBJE) methodology in the framework of single-lap multi-bolt joints analysis. This FE modeling approach exploits the CBJE, a user-defined finite element. It is founded on the complete elastic characterization of the bolted region through analytical models. The elastic behavior of a circular portion of the laminates enclosing the bolt is determined in the context of thick composite plate mechanics; a set of radial beam elements is made structurally equivalent through the custom definition of their stiffness matrix. The interaction between the bolt and the plates is modeled as a beam on elastic foundation. The stiffness contributions of the bolt and the specific properties of the joint, such as preload, bolt-hole clearance, contact stiffness, and friction effects are simulated utilizing an assembly of beam and spring elements. In this way, it is created a FE model from the theoretical solution of the bolted region featuring high fidelity and computational efficiency, as it requires a low amount of degrees of freedom. Experimental data are used to validate the FE model with CBJE of the single-lap three-bolt composite joint. Specimens with varying lay-up, radial clearances, bolts preload and bolt number are also analyzed to evaluate the bolt load distribution and out-of-plane behavior. The CBJE results are successfully compared with those of reference solid models
FE analysis of single-bolt composite bolted joint by means of a simplified modeling technique
No full textThe new Composite Bolted Joint Element (CBJE) is applied to the FE analysis of a single-lap, single-bolt composite bolted joint, allowing for important reductions of the computational burden while maintaining remarkable accuracy of results. The CBJE is a user-defined finite element representative of the elastic behavior of the region comprising the bolted joint and a portion of the surrounding composite plates. This modeling approach exploits radially disposed beam-shaped elements whose stiffness matrix is defined according to the analytical solution of the theoretical reference model of composite bolted joints, previously attained by the authors. This allows establishing the structural equivalence between the FE model and the theoretical reference model of the joint. A comparative investigation between a full detailed 3D FE model and a shell one featuring the CBJE of the single-lap joint is presented. It demonstrates the capabilities of the CBJE to synthesize low simulation time requirements and outcomes exactness. © 201
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