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Doctoral Thesis
DOI
https://doi.org/10.11606/T.18.2016.tde-12022016-105116
Document
Author
Full name
Mariano Eduardo Moreno
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2006
Supervisor
Committee
Lirani, João (President)
Al-Qureshi, Hazim Ali
Button, Sergio Tonini
Massaroppi Junior, Ernesto
Proença, Sergio Persival Baroncini
Title in Portuguese
Determinação numérica da curva limite de estabilidade quanto à flambagem plástica em chapas metálicas
Keywords in Portuguese
Conformação de chapas metálicas
Diagramas limite de estabilidade
Enrugamento
Flambagem plástica
Método dos elementos finitos
Abstract in Portuguese
Dentre os principais problemas que ocorrem na estampagem de chapas metálicas estão a fratura, e estricção (necking) e o enrugamento (wrinkling). Este último pode fazer com que a peça fabricada seja rejeitada por problemas que vão desde motivos estéticos até dificuldades de montagem destas peças e desgaste excessivo da ferramenta. Diversos pesquisadores tem estudado o problema de instabilidade à compressão que origina o fenômeno de enrugamento. Pretende-se estudar os principais métodos para predição do enrugamento, a saber, a teoria da bifurcação, a introdução de uma falha induzida e a aplicação do indicador proposto por Nordlund e Häggblad (coeficiente NH). O método escolhido será implementado junto a um programa de análise por elementos finitos de modo a obter diagramas limite de estabilidade, para então ser aplicado a peças mais genéricas. O procedimento é aplicado a peças de geometria relevante para serem ensaiadas experimentalmente de modo a validar as simulações numéricas propostas.
Title in English
Numerical determination of the stability Iimit curve applied to plastic buckling in sheet metal forming operation
Keywords in English
Finite element method
Plastic buckling
Sheet metal forming
Stability limit diagrams
Wrinkling
Abstract in English
Among the main problems in sheet metal forming processes are the fracture, the necking and the wrinkling behavior of the material. The last one can produce rejected parts due difficulties in the assembly of these parts or excessive wear of the tooling. Many researchers have been studied the problem of the compression instability phenomenon that origins the wrinkling behavior. The objective of this work is the study of the main available methods to the wrinkling prediction, as the bifurcation theory, the induced defect and an indicator proposed by Nordlund and Häggblad (NH coefficient). The more suitable method is implemented into a finite element analysis software in order to obtain the stability limit diagrams that can be used in the design of generic shape parts. Experimental studies will be done in parts subjected to compressive forming loads in order to validate the numerical simulations.
 
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Publishing Date
2016-02-12
 
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