The 4‐node assumed strain elements are among the best elements available today but the bending moments at their full integration points oscillate severely. This paper presents a…
Abstract
The 4‐node assumed strain elements are among the best elements available today but the bending moments at their full integration points oscillate severely. This paper presents a one point integrated version of the 4‐node assumed strain plate element of Bathe‐Dvorkin. A Taylor series expansion approach is used to accommodate the linear variation of strains/stresses within the element and hence to stabilize the spurious zero energy modes. An extensive number of benchmark results are presented and compared.
Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the…
Abstract
Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore aims to give the reader an encyclopaedic view on the subject. The bibliography at the end of the paper contains 2,025 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1992‐1995.
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Mohammad Rezaiee-Pajand, Nima Gharaei-Moghaddam and Mohammadreza Ramezani
This paper aims to propose a new robust membrane finite element for the analysis of plane problems. The suggested element has triangular geometry. Four nodes and 11 degrees of…
Abstract
Purpose
This paper aims to propose a new robust membrane finite element for the analysis of plane problems. The suggested element has triangular geometry. Four nodes and 11 degrees of freedom (DOF) are considered for the element. Each of the three vertex nodes has three DOF, two displacements and one drilling. The fourth node that is located inside the element has only two translational DOF.
Design/methodology/approach
The suggested formulation is based on the assumed strain method and satisfies both compatibility and equilibrium conditions within each element. This establishment results in higher insensitivity to the mesh distortion. Enforcement of the equilibrium condition to the assumed strain field leads to considerably high accuracy of the developed formulation.
Findings
To show the merits of the suggested plane element, its different properties, including insensitivity to mesh distortion, particularly under transverse shear forces, immunities to the various locking phenomena and convergence of the element are studied. The obtained results demonstrate the superiority of the suggested element compared with many of the available robust membrane elements.
Originality/value
According to the attained results, the proposed element performs better than the well-known displacement-based elements such as linear strain triangular element, Q4 and Q8 and even is comparable with robust modified membrane elements.
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J. Sorić, U. Montag and W.B. Krätzig
Presents a robust and unconditionally stable return‐mapping algorithm based on the discrete counterpart of the principle of maximum plastic dissipation. Develops the explicit…
Abstract
Presents a robust and unconditionally stable return‐mapping algorithm based on the discrete counterpart of the principle of maximum plastic dissipation. Develops the explicit expression for the consistent elasto‐plastic tangent modulus. All expressions are derived via tensor formulation showing the advantage over the classical matrix notation. The integration algorithm is implemented in the formulation of the four‐node isoparametric assumed‐strain finite‐rotation shell element employing the Mindlin‐Reissner‐type shell model. By applying the layered model, plastic zones can be displayed through the shell thickness. Material non‐linearity described by the von Mises yield criterion and isotropic hardening is combined with a geometrically non‐linear response assuming finite rotations. Numerical examples illustrate the efficiency of the present formulation in conjunction with the standard Newton iteration approach, in which no line search procedures are required. Demonstrates the excellent performance of the algorithm for large time respective load steps.
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The purpose of this article is to attempt to highlight various approaches for enhancing the viability of probiotics, with special emphasis on micro‐encapsulation.
Abstract
Purpose
The purpose of this article is to attempt to highlight various approaches for enhancing the viability of probiotics, with special emphasis on micro‐encapsulation.
Design/methodology/approach
Various techniques, such as selection of acid and bile resistant strains, use of oxygen impermeable packaging materials, two‐step fermentation, stress adaptation, inclusion of micro‐nutrient, sonication of bacteria and micro‐encapsulation, which could be employed for maintaining or enhancing probiotic viability are discussed, with special emphasis on micro‐encapsulation.
Findings
Probiotics lose their viability during gastro‐intestinal transit due to unfavorable intestinal environment. Amongst diverse techniques micro‐encapsulation could confer protection to the probiotics both in the product as well as in the gastro‐intestinal environment.
Originality/value
The paper shows that micro‐encapsulation of probiotics renders them stable both in the product as well as in the intestinal environment and application of encapsulated probiotics would result in a product with greater prophylactic activities.
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Probiotics are known to extend health benefits and therefore may be included during yoghurt manufacture to enhance its prophylactic properties. Different probiotic strains may…
Abstract
Purpose
Probiotics are known to extend health benefits and therefore may be included during yoghurt manufacture to enhance its prophylactic properties. Different probiotic strains may exhibit diverse biotechnological behaviour in association with yoghurt cultures, therefore interactive behaviour amongst probiotic and yoghurt cultures must be evaluated prior to their commercial application. This paper aims to assess the effect of inclusion of different probiotic cultures on various biotechnological (technological, dietetic and prophylactic) characteristics of yoghurt cultures.
Design/methodology/approach
Yoghurt was assessed for technological characteristics based on acidification and flavour production, dietetic characteristics based on proteolytic activity, vitamin synthesis and L (+) lactic acid production and prophylactic characteristics based on β‐galactosidase activity, antibacterial spectrum, viability in product as well as during gastro‐intestinal transit, intestinal colonization, immunomodulation, anti‐carcinogenicity and hypocholesterolemic effect.
Findings
Different probiotic cultures exhibited diverse technological, dietetic and prophylactic behaviour in association with yoghurt cultures. Functional properties of traditional yoghurt could be enhanced with the combined introduction of probiotic cultures such as Bifidobacterium bifidum, Bifidobacterium infantis and Lactobacillus acidophilus and the resultant product may be recommended for consumption as a dietary adjunct.
Originality/value
The paper shows that combined introduction of probiotic cultures such as B. bifidum, B. infantis and L. acidophilus, as microbial additives during the manufacture of yoghurt would result in a product with enhanced functional properties.