Use Of Fillets Research Articles

Cohesive failure analysis of carbon-fiber composite patch repair in perforated steel tubular elements

The use of composite materials to repair corroded steel structural components has expanded in the offshore oil and gas sector. The effective use of composites requires a meticulous process for choosing appropriate constituent elements. In this regard, numerical modeling is an efficient tool to better understand the impact of associated variables and enables the identification of failure causes and simulation of failure propagation. This study aims to assess the mechanical behavior of the adhesive layer at the steel - composite material interface in the repair of perforated tubular structures under bending, compression, and bending-compression. A numerical model is developed simplifying the examination and characterization of the cohesive failure mechanisms and modes occurring between the laminate patch repair and the perforated steel tubular element. The stress distribution and cohesive failure at the interface are then thoroughly investigated. The impacts of the inclusion of fillets at the patch repair ends to smoothen the transition between the composite material and the tube and the repair length are also evaluated. A Python subroutine is developed to identify the failure mode mechanisms to characterize the adhesive areas subjected to peel, shear, or mixed modes. Results suggest that pure shear mode is predominant in most of the repair locations across the three types of loading. For bending loads, the cohesive failure close to the cutout shows prominent shear mode. In the other loading conditions, the adhesive nearly fails in the vicinity of the cutouts (i.e., damage values are close to 1) in a predominant near pure shear failure mechanism. The use of fillets displaces the failure location for bending load, hence increasing the failure load level. Repairs were more extensive under Bending Moment load conditions compared to other load types. The mode ratio analysis and methodology presented in this work offer valuable tools for understanding the causes of failure modes.

Structural study of a polymeric aortic valve prosthesis. Analysis for a hyperelastic material

This work presents a structural computational simulation of a polymeric aortic valve prosthesis, made with a hyperelastic material (Styrene-Ethylene/Propylene-Styrene). The valve has a suture ring, three pillars placed at 120° and three leaflets. The analysis is based on a modification over previous designs consisting in a fillet concave surface to avoid stress concentration at the junctions between leaflets and pillars. Three shapes were simulated. The first one was used to validate the computational method by comparison of the results with a recent paper. The second shape was designed to show that a fillet or “rounding” can be beneficial to the stress leaflet reduction. The third shape was also designed to show that the reduction of leaflet thickness and intercommissural distance between leaflets at the pillar junctions improves the valve opening and closure. The use of fillet with a 0.5 mm radius, reduced 26.5% the maximum Von Mises stresses for the second shape and 33.9% for the third shape. Additionally, for the latter, the opening area was not affected for the high stiffness due to fillet. The results -mainly for the third shape-are promising and give rise to future studies: further shape optimization, analysis for other materials and valve simulation under pathological loads.

Технология ремонта бетонных облицовок каналов битумно-полимерной мастикой

Purpose: development of technology for repairing canal linings concrete with bitumen-polymer mastic using one- and two-component latex emulsion to reduce water loss through defects in the concrete lining. Materials and methods: the technology of repairing the damaged canal lining concrete coating includes: preparation of the base for the protective coating; preparation of bitumen-polymer mastic for its application (manually) or spraying (mechanized) over the entire repaired area; preparation of equipment, mechanisms and necessary inventory; preparation for the use of material components (reagent (component A) and hardener (component B)) for mechanized application; the process of applying bitumen-polymer mastic to the repaired area. Results: according to the results of a scientific research, when repairing the internal junctions of the bottom and slopes of canal concrete linings, it is necessary to arrange fillets that have a triangle with sides 10–50 mm long in their cross-section. The use of fillets when joining concrete linings will avoid excessive consumption of repair material. The application of a one-component material is carried out manually using a spatula to repair minor damage and reduce losses through them, and the application of a two-component mastic will allow mechanized repair of the largest (areal) damage. Conclusions: the application of one- and two-component cold-curing bitumen-polymer mastic for repairing concrete lining of irrigation canals to various damages on their surface (cracks, shears, concrete scaling, destroyed seams, etc.) is considered. Technological operations for the repair and restoration of canal concrete linings (a technological map for the concrete surfaces repair with a mechanized polymer composite material has been developed), including five stages of work are presented.

Rational Use of Fillet Welds and Butt-fillet Welds in Welded Constructions

The study contains quantitative conditions and limitations of the use of butt, fillet and butt-fillet welds in modern welded constructions. Examples of improper use are given. Calculated loss of material and capacity structures associated with the use of fillet welds with a convex face, their asymmetry, as well as the benefits of in-depth penetration obtained by hybrid or other, leading to the achievement of butt welds and butt-fillet welds with high-efficiency welding technologies. A list of the requirements for the correct use of fillet welds and features differing from butt, butt-fillet and fillet welds is given.

Ripening of salted anchovy (Engraulis anchoita): development of lipid oxidation, colour and other sensorial characteristics

Changes in lipids are in general associated with quality deterioration, though earlier studies in anchovy indicate that the volatile compounds of importance to the characteristic flavour could be generated by lipid oxidation. The aim of the present paper was to study the changes in the fatty acid composition and the lipid oxidation of Engraulis anchoita during ripening and their relationship with the development of the typical sensorial characteristics. As a result of ripening, polyunsaturated fatty acids decrease from 4.27 to 2.42 and 2.00 g kg(-1) fatty acids in gutted fish and fillet, respectively. The most affected class of fatty acids was the n-3 fatty acids, especially docosahexaenoic acid. Moreover, saturated fatty acids were the most stable to the process. 2-Thiobarbituric acid reactive substances (TBARS) increased throughout ripening, and the use of fillets instead of gutted fish reduced this value. The a value was the parameter most modified, showing a marked increase which correlates with the acquisition of a uniform pink colour. Sensory analysis did not show development of off-odour or undesirable changes in colour during ripening. As a result of ripening, the fatty acid profile was modified and an increment of TBARS was observed. However, these changes did not lead to deterioration in the quality of the product.

Complex Reconstruction of a Massive Shoulder and Chest Wall Defect: De-Bone Appétit Flap

We report the use of a fillet of upper arm pedicled flap, which has not been previously reported in the literature. The fillet of upper arm flap follows the principle of “spare parts” surgery, and can provide vascularized soft tissue coverage for defects of the shoulder and the chest wall when the upper extremity cannot otherwise be salvaged, such as in cases of radical tumor excision.The fillet of upper arm pedicled flap was used to successfully cover a large shoulder and chest wall defect measuring 25 cm x 15 cm. This “spare parts” reconstructive technique has several advantages over the previously reported forearm free flap, including minimal need for microsurgery and the ability for expansion to cover larger defects. This case demonstrates effective use of fillet of upper arm flaps in reconstruction of large defects of the shoulder and chest wall.

Computational Modelling of the Residual Strength of Repaired Composite Laminates Using a Cohesive Damage Model

This work reports on a three-dimensional numerical analysis to assess the residual strength of single and double-strap repaired CFRP composite laminates, under tensile, compressive and bending loads. Interface finite elements including a triangular cohesive mixed-mode damage model are used in order to simulate damage onset and growth. The influences of several geometric changes on damage onset as well as growth and on the repair residual strength are addressed. The geometric changes include chamfering the outer and inner patch faces, filling the drilled hole with adhesive (plug filling), use of fillets of different shapes and dimensions at the outer edge of the overlap, chamfering the outer and inner parent laminate faces and combinations thereof. This work showed that with the correct repair geometry, a significant strength improvement could be achieved for all the loads considered and for both single and double-strap geometries. © Koninklijke Brill NV, Leiden, 2008

Effect of a rotor's aspect ratio and casing inlet/outlet geometry on the efficiency of a rotor-casing assembly

Computational fluid dynamics (CFD) simulation was used to study the effect of modifying the inlet and outlet of an elliptical rotor-casing assembly at two different rotor aspect ratios. The simulations were carried at different inlet velocities and rotor angular speeds. The flow field results were used to ascertain the changes in the efficiency of the rotor-casing assembly. The focus was on inlet pressure, maximum velocity, and maximum turbulence values. Entropy calculations were also used to evaluate the impact of the different configurations on the overall thermodynamic efficiency of the rotor-casing assembly. The results show the use of fillets has several advantages, especially when using high aspect-ratio rotors at high rpm values.

Effect of a rotor's aspect ratio and casing inlet/outlet geometry on the efficiency of a rotor-casing assembly

Computational fluid dynamics (CFD) simulation was used to study the effect of modifying the inlet and outlet of an elliptical rotor-casing assembly at two different rotor aspect ratios. The simulations were carried at different inlet velocities and rotor angular speeds. The flow field results were used to ascertain the changes in the efficiency of the rotor-casing assembly. The focus was on inlet pressure, maximum velocity, and maximum turbulence values. Entropy calculations were also used to evaluate the impact of the different configurations on the overall thermodynamic efficiency of the rotor-casing assembly. The results show the use of fillets has several advantages, especially when using high aspect-ratio rotors at high rpm values.

Estimating the quantitative essential amino acid requirements of striped bass Morone saxatilis , using fillet A/E ratios

In order to determine the essential amino acid requirements (EAA) of striped bass Morone saxatilis, fillets were analysed to ascertain the relative amino acid concentrations for determining A/E ratios ((EAA/total EAA) × 1000)). Analysis of the striped bass fillets yielded the following concentrations of essential amino acids (g kg–1) and A/E ratios, respectively: arginine, 12.5, 115; histidine, 5.1, 47; isoleucine, 8.0, 74; leucine, 17.1, 157; lysine, 20.2, 186; methionine + cysteine, 9.2, 85; phenylalanine + tyrosine, 16.0, 147; threonine, 9.8, 90; tryptophan, 1.9, 18; and valine, 9.1, 84. In two experiments, diets with graded levels of EAA were fed to striped bass weighing 111 ± 3 g and 790 ± 122 g per fish, respectively. In both experiments, the dietary A/E ratios were maintained in the same relative concentrations as determined in the striped bass fillets. Statistical analysis of weight gains, feed conversions and nitrogen balance indicated significant differences (P < 0.05) between treatments. Non-linear regression analysis of the response criteria pooled from both experiments yielded the following estimates of dietary EAA requirements (g kg–1 dry diet) when digestible energy equalled 13.39 MJ kg–1 diet: arginine, 14; histidine, 6; isoleucine, 9; leucine, 19; lysine, 22; methionine + cysteine, 10; phenylalanine + tyrosine, 17; threonine, 11; tryptophan, 3; and valine, 10. The use of fillet A/E ratios allows for the rapid estimation of quantitative EAA requirements and the development of species specific diets for new aquaculture species. The data presented here are the first to simultaneously describe all the dietary EAA requirements for M. saxatilis.

Reflections on the mechanical structure of the base of the skull and of the face. Part 2: Discussion, current concepts and theories.

Using thick sections of the base of the skull and face their mechanical structure is viewed from the engineering aspect and the anatomic solutions evolved are compared with those selected by Aerospatiale engineers for the concept and development of the Airbus. It is concluded that the anterior and middle cranial fossae, together with the face, constitute an inseparable mechanical assembly each of whose component units participate in the rigidity of the others. Since this mechanical assembly must provide maximal rigidity for minimal weight, this suggests that aeronautical solutions should throw much light on the detail of construction of the skull and face. Indeed, the rigidity and lightness of the latter are obtained by means of solutions familiar in aeronautics: the reliance on thin-shelled beams with a honeycomb filling, the diploe analogous to a preconstrained composite or sandwich structure, a system of frames, struts and stiffeners, and the use of fillets at the sites of junction of struts.

Reflections on the mechanical structure of the base of the skull and on the face

Using thick sections of the base of the skull and face their mechanical structure is viewed from the engineering aspect and the anatomic solutions evolved are compared with those selected by Aerospatiale engineers for the concept and development of the Airbus. It is concluded that the anterior and middle cranial fossae, together with the face, constitute an inseparable mechanical assembly each of whose component units participate in the rigidity of the others. Since this mechanical assembly must provide maximal rigidity for minimal weight, this suggests that aeronautical solutions should throw much light on the detail of construction of the skull and face. Indeed, the rigidity and lightness of the latter are obtained by means of solutions familiar in aeronautics: the reliance on thin-shelled beams with a honeycomb filling, the diploe analogous to a preconstrained composite or sandwich structure, a system of frames, struts and stiffeners, and the use of fillets at the sites of junction of struts.