Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Pure and applied geophysics 143 (1994), S. 483-510 
    ISSN: 1420-9136
    Keywords: Temperature ; strength ; thermo-plasticity ; brittle-plastic transition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Mechanical properties of rocks change under the influence of, temperature. Stress at the onset of yielding, ultimate strength, dilatancy, strain hardening and softening, and the confining pressure at brittle-ductile transition are all reduced by the increasing temperature. This study presents a framework of constitutive modeling of thermo-brittle-plastic behavior of rocks which encompasses these changes. The constitutive law is based on a thermo-plasticity theory first proposed for metals byPrager (1958). Two phenomenological mechanisms have been identified as central for the modeling: temperature dependence of the yield locus (thermal softening), and temperature dependence of the strain-hardening function (thermally enhanced ductility). Material parameters for two rocks, Carrara marble and Westerly granite, were determined on the basis of additional hypotheses. These parameters are used in numerical simulations of triaxial tests at different temperatures. The obtained stress-strain curves compare well to the experimental results. The changes with temperature in the stress at the onset of yielding are more accurately reproduced that the evolution of hardening or softening. Suggestions for possible improvements and future research directions are indicated.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Meccanica 11 (1976), S. 42-47 
    ISSN: 1572-9648
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Summary In the vicinity of structural discontinuities such as cut-outs, stiffeners and support attachments high order polynomials approximate the peak stresses occurring there better than conventional low order ones, provided only the minimal continuity requirements are enforced. When transverse shear energy is neglected, C 1 continuity (continuity of both functional values and normal derivatives along interelemental boundaries) and no more than C 1 continuity has to be enforced. In particular continuity of second derivatives at vertices must be avoided. Here a family of C 1 triangular elements with arbitrary order of polynomial interpolation is created. The algorithm has been devised in such a way that convergence to the correct solution can be seeked by increasing the polynomial degree instead of decreasing the element size. This process becomes now as inexpensive as possible and particularly suited for automation.
    Notes: Sommario Nei pressi di discontinuità strutturali (aperture, intagli, nervature, ecc.) polinomi di grado elevato approssimano le concentrazioni di sforzo meglio degli usuali polinomi di basso grado, purchè la continuità interelementare non ecceda i requisiti variazionali. Perciò nella teoria di Kirchoff solo la continuità C 1 (continuità della funzione e delle sue derivate prime) deve essere soddisfatta. In particolare la continuità delle derivate seconde ai vertici deve essere evitata. Nella nota si crea una famiglia di elementi triangolari di continuità C 1 e con arbitrario grado dei polinomi interpolanti. L'algoritmo consente il calcolo sul medesimo reticolo di una sequenza di soluzioni di crescente accuratezza aumentando il grado dei polinomi approssimanti. La ricerca della convergenza diventa molto meno onerosa ed è suscettibile di automatizzazione.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 14 (1979), S. 1273-1291 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Finite element interpolations of arbitrary polynomial degree which are exactly and minimally C1 continuous across interelement boundaries are studied. A perspective view of the techniques proposed by other authors is presented and some new possibilities are considered. The problem is discussed with reference to the plate and shell finite element approximations, based on the principle of minimum potential energy. The approach also permits identification of sufficient conditions for guaranteeing full rank of stiffness matrices based on modified principles of potential energy. The results of this analysis can be used to investigate the linear dependencies among nodal variables which also occur in the formulation of other fourth-order problems.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 14 (1979), S. 1872-1874 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 18 (1982), S. 311-313 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Communications in Applied Numerical Methods 3 (1987), S. 97-101 
    ISSN: 0748-8025
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Simple formulae are provided in order to detect distorted shapes of solid elements which actually correspond to inadmissible overlapping at vertices. As pathological situations still pass the zero-order patch test, factors controlling the behaviour of extremely distorted or overlapped elements are discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...