Search results for " Structural"

A cohesive interface model for the structural mechanics of block masonry

1997

Analysis of stress concentration during tension of round pultruded composite rods

2008

The stress state in a solid round transversely isotropic rod loaded with balanced shear stresses on a part of its lateral surface is considered. The change in gripping conditions is simulated by varying the distribution of statically equivalent shear stresses. The solution for the stress state was obtained using exact equations of linear theory of elasticity of anisotropic body. An analysis of the distribution of longitudinal and hoop stresses showed that at the grip edges a very high stress concentration is possible, which depends on the radius of the tensioned rod and the distribution of shear stresses on the gripped surface. At the grip edges, the longitudinal and hoop stresses tend to i…

Effects of natural fibres reinforcement in lime plasters (kenaf and sisal vs. Polypropylene)

2014

Nowadays the tendency to realize environment-friendly products is becoming more widespread to ensure sustainable and smart development. The synthetic fibres, frequently used, are harmful to the environment because they are non-degradable and non-renewable. Their use has resulted in an increase of oil consumption. Therefore, the possibility of replacing them with natural fibres becomes increasingly concrete confirmed by the researches and investigations carried out. In this work three lime based plasters were prepared and analysed to evaluate the influence on their performance of different fibres used as reinforcement. In particular each plaster was realised by adding to the mortar the same …

Modeling of ITER TF cooling system through 2D thermal analyses and enthalpy balance

2017

Abstract The winding pack of the ITER Toroidal Field (TF) coils is composed of 134 turns of Nb3Sn Cable in Conduit Conductor (CICCs) wound in 7 double pancakes and cooled by supercritical helium (He) at cryogenic temperature. The cooling of the Stainless Steel (SS) case supporting the winding pack is guaranteed by He circulation in 74 parallel channels. A 2D approach to compute the temperature distribution in the ITER TF winding pack is here proposed. The TF is divided in 32 poloidal segments, for each segment the corresponding 2D model is built and a thermal analysis is performed applying the corresponding nuclear heating computed with MCNP code considering the latest design updates, such …

Stress field model for strengthening of shear-flexure critical RC beams

2017

A model for the design of shear-flexure critical reinforced concrete elements strengthened with fiber-reinforced polymer (FRP) sheets and plates is presented. The model is based on the stress field approach and the equilibrium method and accounts for the different failure modes of FRP, focusing on the debonding of the FRP from the concrete surface. The efficiency of the model in the strength assessment of beams reinforced with FRP by the prediction of the shear-flexure capacity is checked by corroborating the results of several experimental tests found in the literature. Moreover, the presented model's capacity to reproduce experimental behavior is compared with the formulations suggested b…

Behaviour of tritium in breeding materials

2005

Abstract The tritium release from ceramic materials of the HCPB under real DEMO operating conditions will depend not only on temperature and neutron flux but also on an intense magnetic field (MF) of 7–9 T. The delay in the tritium release induced by the MF is proportional to the grain size of the ceramics, the squared MF intensity and the abundance ratio of charged tritium forms (T + , T − ) in the grain volume of the ceramics. The effect of MFs of different intensity on the tritium release from the Li 4 SiO 4 pebbles irradiated in the EXOTIC-8 experiment (neutron fluence 2.4 × 10 25  n m −2 , irradiation temperature up to 700 K) was investigated in this study. As a result of the irradiati…

Influence of chemisorption products of carbon dioxide and water vapour on radiolysis of tritium breeder

2014

Abstract Lithium orthosilicate pebbles with 2.5 wt% excess of silica are the reference tritium breeding material for the European solid breeder test blanket modules. On the surface of the pebbles chemisorption products of carbon dioxide and water vapour (lithium carbonate and hydroxide) may accumulate during the fabrication process. In this study the influence of the chemisorption products on radiolysis of the pebbles was investigated. Using nanosized lithium orthosilicate powders, factors, which can influence the formation and radiolysis of the chemisorption products, were determined and described as well. The formation of radiation-induced defects and radiolysis products was studied with …

Physicochemical processes in blanket ceramic materials

2003

Abstract Effect of external magnetic field (MF) on important physicochemical processes in ceramic blanket materials, the Li4SiO4 (FZK) and Li2TiO3 (CEA) ceramic pebbles, was studied. Stoichiometric amounts of the radiation-induced defects (RD) of the electron and hole type form at radiolysis of the ceramic materials. Colloid lithium forms only in Li4SiO4 under irradiation at the temperature 423–473 K and the dose 10–20 MGy. The magnetic field increases the radiolysis efficiency by 20–25% in both materials. The efficiency of formation of RD decreases with the increasing temperature of irradiation. Complete recombination of RD takes place at 873 K. The magnetic field retards the tritium relea…

Magneto-Electro-Elastic Bimorph Analysis by the Boundary Element Method

2008

The influence of the magnetic configuration on the behavior of magneto-electro-elastic bimorph beams is analyzed by using a boundary element approach. The problem is formulated by using the generalized displacements and generalized tractions. The boundary integral equation formulation is obtained by extending the reciprocity theorem to magneto-electro-elastic problems; it is numerically implemented by using the boundary element method multidomain technique to address problems involving nonhomogeneous configurations. Results under different magnetic configurations are compared highlighting the characteristic features of magnetopiezoelectric behavior particularly focusing on the link between …

Shear Capacity Model with Variable Orientation of Concrete Stress Field for RC Beams Strengthened by FRP with Different Inclinations

2021

A design-oriented analytical model able to evaluate the shear capacity of reinforced concrete (RC) beams strengthened with fiber-reinforced polymer (FRP) sheets or strips oriented in any direction is proposed. The formulation of the model is based on the variable-inclination stress-field approach, aiming to extend the provisions of current European standards to beams strengthened in shear using FRP. The main novelty of the model lies in taking into account the possible different inclination of steel stirrup and FRP reinforcement in determining the orientation of a compressed concrete stress field, and in shear strength evaluation, overcoming the approximation of the known models with variab…