We focus on a variational model of an elastic-plastic beam which is clamped at both endpoints and subject to a transverse L(infinity) load: the mathematical formulation is a 1D free discontinuity problem with second-order energy dependent on gradient-jump integrals but not on the cardinality of gradient-discontinuity set. The related energy is not lower semicontinuous in BH; moreover the relaxed energy is finite also when second derivatives have Cantor part. Nevertheless we show that if a safe load condition is fulfilled, then minimizers exist and they actually belong to SBH, say their second derivative has no Cantor part. If in addition a stronger condition on load is fulfilled, then minimizer is unique and belongs to H(2). Moreover, we can always select one minimizer whose number of plastic hinges does not exceed 2 and is the limit of minimizers of penalized problems. When the load stays in the gap between safe load and regularity condition, then minimizers with hinges are allowed; if in addition the load is symmetric and strictly positive, then there is uniqueness of minimizer, the hinges of such minimizer are exactly two and they are located at the endpoints.
A Variational Principle For Plastic Hinges In A Beam / D. Percivale;F. Tomarelli. - In: MATHEMATICAL MODELS AND METHODS IN APPLIED SCIENCES. - ISSN 0218-2025. - STAMPA. - 19(2009), pp. 2263-2297.
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Titolo: | A Variational Principle For Plastic Hinges In A Beam |
Autori: | |
Data di pubblicazione: | 2009 |
Rivista: | |
Citazione: | A Variational Principle For Plastic Hinges In A Beam / D. Percivale;F. Tomarelli. - In: MATHEMATICAL MODELS AND METHODS IN APPLIED SCIENCES. - ISSN 0218-2025. - STAMPA. - 19(2009), pp. 2263-2297. |
Abstract: | We focus on a variational model of an elastic-plastic beam which is clamped at both endpoints and subject to a transverse L(infinity) load: the mathematical formulation is a 1D free discontinuity problem with second-order energy dependent on gradient-jump integrals but not on the cardinality of gradient-discontinuity set. The related energy is not lower semicontinuous in BH; moreover the relaxed energy is finite also when second derivatives have Cantor part. Nevertheless we show that if a safe load condition is fulfilled, then minimizers exist and they actually belong to SBH, say their second derivative has no Cantor part. If in addition a stronger condition on load is fulfilled, then minimizer is unique and belongs to H(2). Moreover, we can always select one minimizer whose number of plastic hinges does not exceed 2 and is the limit of minimizers of penalized problems. When the load stays in the gap between safe load and regularity condition, then minimizers with hinges are allowed; if in addition the load is symmetric and strictly positive, then there is uniqueness of minimizer, the hinges of such minimizer are exactly two and they are located at the endpoints. |
Handle: | http://hdl.handle.net/11567/424133 |
Appare nelle tipologie: | 01.01 - Articolo su rivista |