Web Width Research Articles

Reconstruction finger web with dorsal two wing-shaped advancement flap for the treatment of congenital syndactyly

To discuss the effectiveness of using dorsal two wing-shaped advancement flap to reconstruct finger web for treatment of congenital syndactyly. Between August 2014 and August 2017, 30 cases of congenital syndactyly were treated, including 18 males and 12 females with an average age of 2.5 years (range, 1.5-5 years). Eight cases were of bilateral hands syndactyly and 22 cases of single hand syndactyly. There were 39 webs of syndactyly (including 1 case of syndactyly of middle finger, ring finger, and little finger). Among them, 11 webs were complete and 28 webs were incomplete. At the dorsum, a flap with V-shaped tip and two wing-shaped pedicle was designed and was just sewed up with an anchor-shaped incision at the palm. Distal end of fingers were separated by serrated flap and were sutured after removal of fatty tissue. In 11 cases with tight skin connection, the defect area at lateral and distal end of fingers was repaired by small pieces of full-thickness skin graft. All the flaps survived completely after operation, and no flap necrosis occurred. The skin grafts on the distal side of the finger survived and the wound healed by first intension. All 30 cases were followed up 6-12 months, with an average of 9 months. Postoperative flexion and extension function of fingers were good, and the web depth and width were normal. At last follow-up, according to the Swanson et al. standard, 20 fingers were graded as excellent, 8 as good, and 2 as fair, with an excellent and good rate of 93.3%. The effectiveness of using dorsal two wing-shaped advancement flap to reconstruction finger web for treatment of congenital syndactyly is satisfactory.

Optimizing Shearer Web Width in Underground Mining of Gently Dipping Methane-Bearing Coal Seams

Optimizing Shearer Web Width in Underground Mining of Gently Dipping Methane-Bearing Coal Seams

Experimental analysis of one-way composite steel deck slabs voided by circular paper tubes: Shear strength and moment–shear interaction

In order to improve structural efficiency, environmental performance, and constructability, a new type of one-way composite voided slab system (TUBEDECK) has been recently proposed which combines profiled steel decks with cast-in-situ RC slabs. Because eliminating concrete volume to optimize flexural strength can significantly reduce the shear strength of nonprestressed concrete or composite slabs without shear reinforcement, a clarification of the shear resistance capacity is required. In this study, shear tests on a total of 12 specimens were conducted with slab thickness, the presence or absence of voids and/or steel decks, and tension reinforcement ratio as variables. The results show that combined flexure and shear dominated the behavior of both voided (V) slabs and TUBEDECK (TD) slabs, and web-shear cracking did not affect strength. Predicted shear strength based on the minimum web width was too conservative. Conversely, the shear strength prediction equations, which were proposed on the basis of the real cross-sectional area of concrete, predicted the capacity of both V slabs and TD slabs from a reasonably conservative perspective. A discussion on the influence of moment–shear interaction is also included, and an interaction design model is proposed in a further investigation.

Effect of forming parameters on edge wrinkling in cold roll forming of wide profiles

The cold roll forming is a continuous metal forming process to produce a large variety of profiles. A major product of the cold roll forming is wide profiles whose application is expanding in the construction of houses, bridges, airports, sports arenas, etc. The edge wrinkling is one of the common defects in the cold roll forming of the wide profiles. The edge wrinkling leads to several problems, such as decrease of dimensional tolerances, abrasion of forming rolls due to contact with the wrinkled edge, non-uniform distribution of forming through the production line, and unsuitable energy consumption. In this paper, the mechanics of edge wrinkling in the cold roll forming of the wide profile is investigated, and the effect of the most important forming parameters on this defect is determined by means of experimental tests and numerical simulations. This research work is performed in St12 steel sheets, and the results show that wrinkling increases with the increase of the outer flange width and inner flange width, while it decreases with the increase of the strip thickness and the distance between the roll stands. Results also show that web width does not have a noticeable effect on the wrinkling.

Innovative use of steel plates to strengthen flange openings in reinforced concrete T-beams

This study suggests using steel plates to strengthen large and small circular, rectangular and square reinforced concrete (RC) T-beam flange openings. Steel plates have been used to compensate for the flange concrete that is removed due to the construction of the openings. The used steel plates were mainly under compressive stresses; therefore, their buckling controlled their strength. Thirteen full-scale T-beams divided into five groups were constructed and tested under two concentrated loads until failure. Three groups dealt with single large openings and two groups dealt with four small openings. All beams had the same reinforcement amount and dimensions of 2500 mm in length, an overall depth of 300 mm, an effective flange width of 390 mm and a 130 mm web width. The results showed that, the presence of unstrengthened single large circular, rectangular and square openings in the flange reduced the T-beam capacity by about 42%, 40% and 34% and increased the midspan deflection by about 25%, 13% and 8%, respectively, when compared with the reference solid beam. After strengthening these large openings using 6 mm steel plates, the ultimate capacity increased by about 34%, 24% and 44%, while the midspan deflection increased by about 24%, 18% and 19% for circular, rectangular and square openings, respectively. On the other hand, the presence of four unstrengthened small circular and rectangular flange openings led to a reduction in the T-beam strength capacity by about 15% and 21%, in addition to increasing the midspan deflection by about 7% and 34%, respectively, when compared with the reference solid beam. Strengthening those small openings using 2 mm steel plates increased the ultimate capacity by about 12% and 16%, as well as increasing the deflection by about 36% and 22% for circular and rectangular openings, respectively.

An analytical-finite-element method for calculating mesh stiffness of spur gear pairs with complicated foundation and crack

Abstract Gear weight optimization is mainly through thin-web and hole in gear foundation. In this paper, an analytical-finite-element model for calculating time-varying mesh stiffness of spur gear pairs with complicated foundation (thin-web and holes) and crack is developed. The pinion and gear foundations are simulated as cylinders and modeled by three-dimensional finite element. The tooth pair is equivalent to a spring and mesh stiffness of a tooth pair is obtained by potential energy method. The spring is rigidly coupled with the pinion and gear foundations. Then, three type examples are presented to verify the model. The first type example is three spur gear pairs with solid foundation. The second type example is gear pairs with thin-web and web holes. And the third example is a gear pair with the cracked foundation. The analysis results show that the model proposed in this paper is applicable and efficient for spur gears with complicated foundation and crack. Finally, the time-varying mesh stiffness is also studied to reveal the effects of web widths, web hole radii and crack lengths.

Embodied Energy Optimization of Prestressed Concrete Slab Bridge Decks

This paper presents one approach to the analysis and design of post-tensioned cast-in-place concrete slab bridge decks. A Simulated Annealing algorithm is applied to two objective functions: (i) the economic cost; and (ii) the embodied energy at different stages of production materials, transport, and construction. The problem involved 33 discrete design variables: five geometrical ones dealing with the thickness of the slab, the inner and exterior web width, and two flange thicknesses; concrete type; prestressing cables, and 26 variables for the reinforcement set-up. The comparison of the results obtained shows two different optimum families, which indicates that the traditional criteria of economic optimization leads to inefficient designs considering the embodied energy. The results indicate that the objectives are not competing functions, and that optimum energy designs are close to the optimum cost designs. The analysis also showed that the savings of each kW h of energy consumed carries an extra cost of 0.49€. The best cost solution presents 5.3% more embodied energy. The best energy solution is 9.7% more expensive than that of minor cost. In addition, the results have showed that the best cost solutions are not the best energy solutions.

Torsional behavior of T- shaped reinforced concrete beams with large web openings

This paper presents the results of an experimental investigation on the behavior of T- shaped RC beams with rectangular web opening under pure torsion. Seven beam specimens were tested in order to study the influence of geometrical parameters on the torsional strength. The investigated parameters were: (1) the flange width, (2) the flange thickness, and (3) the opening height. All specimens had the same span, same depth, same web width and same opening length. All beams were loaded till failure. Cracking patterns were monitored and systematic measurements were taken to draw the torque-angle of rotation curves. The results are analyzed to study the effects of the studied parameters on the cracking torque, the ultimate torque, the angle of rotation at cracking, the angle of rotation at ultimate, and failure modes. The analysis of testing results highlights several key aspects to provide a set of recommendations for such beams. The experimental results show that the geometrical parameters (flange width, flange height, and opening height) have a profound effect on the behavior of T-shaped RC beams under pure torsion. A new analytical model based on softened truss model has been used for predicting the torsional behavior of the tested beams. The softened truss model has been successively used for torsion, which is extended to T-shaped RC beams with large web opening under pure torsion. The analytical torque-rotation curves were compared with the experimental ones and observations were noted.

Investigation of torsional behavior and capacity of reactive powder concrete (RPC) of hollow T-beam

A hollow reinforced concrete T-beams were investigated under the effect of pure tension experimentally, which are made of reactive powder concrete (RPC). This concrete was produced with adding steel fiber and silica fume in different dosages. The present work aims at studying the effect of the steel fiber volumetric ratio (Vf) and silica fume content (Sf) on the behavior of hollow T-beam under pure torsion and so, on its torsional capacity. For this purpose T-beams were simply supported with 1400mm length, 100mm web width, flange width 220mm and 160mm height were tested. It was found that the addition of 2% steel fibers to concrete mix increased the cracking and ultimate torque of the RPC hollow T-beam. An increase of 184% in cracking torque and 66% in ultimate torque for hollow section was achieved while the other properties kept constant.

Development of High-Material-Usage Manufacturing Process for Precision Components by Lateral Forming with Tablet-Shaped Blank Material

Fine blanking (FB) is well known as a method for obtaining a clean-cut edge in the manufacture of a plate-like part having a sliding portion and/or a fitting portion on the side face of the part. However, FB in general is disadvantageous for good usage of precious steel material because of the unavoidable large web width. Accordingly, to manufacture precision plate-like parts with high material usage, first, a strip material having a thickness corresponding to the thickness of the finished product was cut from the coil material. Then, forming was carried out from the side of the plate surface with a punch and a knock -out punch in which the shape close to the final product was divided into approximately half. Thereafter, the forged product, which includes the defects from cutting, was blanked into the final product shape while being restrained by part of the side wall of the die. The method resulted not only in precious stainless-steel components,such as small arms used in large number in an automobile turbocharger, each having a clean-cut edge without fracture along the sheet thickness, but also in drastically improved material usage.

Experimental and Numerical Investigation of Octagonal Partially Encased Composite Columns Subject to Axial and Torsion Moment Loading

This paper includes experimental and numerical study of the octagonal partially encased composite (PEC) columns specimens under axial and torsion loading. The major difference between them was the concrete reinforcement details. The parameters investigated in the experimental and numerical study were the type of reinforcement details, the failure mode, width-to-thickness ratio of flange, transverse links spacing and diameter. The results were presented as load-deformation curves. Numerical model was validated using finite element method and the results indicated acceptable accuracy with tests results in the form of capacity and ductility. In the analytical phase, the experimental results in the compressive loading were compared with those obtained from CSA S16-14 and EN 1994-1-1 equations. Also, the new concrete confinement factor in proportion to the web width to thickness ratio was presented to octagonal PEC columns under pure compressive load. Furthermore, different types of retrofit of cross-shaped steel column including concrete encasement, use of stiffener plates and transverse links were investigated in this research. Results revealed that concrete confinement and use of transverse links had respectively the most and the least effect on increasing torsional capacity of the specimens.

Elastic buckling analysis of webs transported through rollers with misalignment

Emerging flexible electronics industries, such as solar cells and RFID tags manufactures, adopt the roll-to-roll (R2R) technology to improve their production efficiency. However, the flexible webs used in these fields wrinkle easily due to their tiny thickness and complex structure. Moreover, the webs are easily buckled if the rollers are misaligned. Therefore, it is desired to introduce an efficient method which can help to determine the critical buckling conditions of the webs when there is misalignment of rolls during their production. The current research presents a model based on the Kirchhoff plates buckling theory to determine the critical buckling misalignment and tension for webs transported through misaligned rollers. Webs are modeled as tensioned Timoshenko beams to obtain their stress distributions. The critical buckling conditions are calculated using the Galerkin method in the current research. Results indicate that the calculated critical conditions are close to the practical ones considering the parabolic variation of shear stress and the linear variation of bending stress. The results also indicate that the critical misalignment increases with the increase of the span ratio and tension, and critical misalignment decreases with the increase of the elastic modulus and web width. Moreover, the critical tension increases as the thickness and elastic modulus increases. The presented model provides a useful method to design and maintain R2R equipment.

Investigation of forming parameters on springback for ultra high strength steel considering Young’s modulus variation in cold roll forming

Ultra High-Strength steels (UHSS) is increasingly used in automotive industry to reduce weight and improve consumers’ safety. However, prediction of springback in cold roll forming is one of the crucial problems to be solved for ensuring dimensional tolerances. The variation of Young's modulus is a significant challenge to accurate springback prediction. In this work, two mechanically-measured tests, such as uniaxial and loading unloading loading cycle test, were performed to determine the Young’s modulus variation with the increase of plastic strain. One mathematical model that considers Young’s modulus variation was proposed and applied in 3D Finite Element Analyses (FEA) to simulate the cold roll forming process. Roll forming tests of hat-shaped section and the relational springback analyses were implemented to compare with FEA simulation results. The calculated accuracy of springback used nonlinear elastic modulus considerably improved by 18% to Swift’s material model. The springback prediction was significantly improved if the Young’s modulus variation was taken into the FEA simulations. The developed model is applied for comparing the effects of different forming parameters on the product springback, showing that springback increases with increasing flange width, sidewall height, roll gap and the distance, decreases with increasing the strip thickness and the web width. The findings are hoped to help roll forming designers predict springback tendency before the roller design is applied in practical production.

Fabrication of Large Area Broadband and Omnidirectional Antireflective Transparent Foils by Roll‐to‐Roll Extrusion Coating

This study investigates the fabrication and performance of broadband and omnidirectional antireflective polymer foils, in the visible spectrum (400–800 nm), consisting of subwavelength inverted moth‐eye structures. The foils are fabricated by a high throughput roll‐to‐roll extrusion coating process allowing structuring on both sides at a rate of 60 m min−1, with web width 45 cm. The highest average transmittance obtained in the visible spectrum is (98 ± 1) %; compared with (92 ± 1) % for the unstructured foil. The antireflective foil shows no significant difference in transmittance between normal incidence and incidence up to at least 60°. The foil performance is also investigated for different depths (Dp) and shapes of structures. The transmittance initially increases with Dp and reaches a maximum at Dp ≈ 120 nm. For process parameters yielding greater depths, other shape factors also play a critical role in the foil's antireflective properties. image

SHEAR BEHAVIOR OF TRAPEZOIDAL BEAMS

Extensive research has been carried out on the behavior and shear strength of reinforced concrete beams. The available literature is voluminous and the state of the art review is given elsewhere. Numerous tests on beams have been conducted and reported in the literature. Many theories for predicting the shear strength have been advanced. The shear strength is based on an average shear stress on full effective cross section (b*d), where b = section width and d = section depth. For calculating shear resistance for Trapezoidal beams with variable width there is many methods and provisions in different codes to calculate the effective width of the section as shown below: -E C: minimum Web width. -ACI 318: average web width. -AASHTO: the minimum of average width and 1.2 min width. -LRFD: Minimum web width. -BS 8110: average web width. Results obtained by experimental work indicated that the shear behavior of the trapezoidal beams depend on the average width of the section.

Experimental and FE analysis of stiffened steel I-column with slender sections

Abstract This paper presents an experimental and a FE analysis of the compressive behavior of slender section columns with and without stiffeners. A series of tests was performed on specimens with different overall heights and different number of stiffeners. A nonlinear three-dimensional FE model was developed using ANSYS program. The efficiency of the nonlinear FE model was verified and a parametric analysis was performed considering variation of number of stiffeners, values of web depth-to-thickness ratio, flange-to-thickness ratio, and slenderness ratio. The load carrying capacity of steel columns with large web-to-thickness ratio is noticeably enhanced up to 34% by increasing number of web stiffeners. Initial imperfection during fabrication should be well controlled and should be carefully considered in the FE modelling. Post local buckling strength of the sections is more sensitive to web width–thickness ratio than flange width–thickness ratio.

Photoconductive zinc oxide-composite paper by pilot paper machine manufacturing

Smart materials can be used for a wide variety of applications, including sensing and energy harvesting. Implementation of smart materials in large area devices requires scalable manufacturing. The use of paper-making techniques would offer an enormous production capacity, allowing for low-cost and large-scale manufacturing. In this work we present a successful pilot scale paper machine manufacturing of functional composite papers (100 m min−1 with a web width of 30 cm) based on cellulose fibres and commercial tetrapodal zinc oxide microwhiskers (ZnO-Ts). Carbon electrodes could successfully be printed on the paper to form complete electronic devices where the paper itself is the active material. This enabled development of a ZnO-composite paper photosensor, where we characterized its stability, sensitivity and speed. The devices show excellent photosensing properties over a wide range of light irradiances (0.01–1 Sun), including short response times (∼10 s) and long-term stability. Under simulated sunlight and a bias voltage of 1 V, small (0.5 cm2) two-probe interdigitated photosensor devices provided 12 μA photocurrent. Under the same conditions, four-probe measurements of the composite paper showed a sheet resistance of 6.9 · 107 Ω/sq. Four-probe measurements also demonstrated that the paper conductivity varies linearly with light irradiance. To the best of our knowledge, this is the first example of pilot paper machine production of an optoelectronic paper, demonstrating the potential for large-scale paper manufacturing of active smart paper from low-cost industrial bulk materials.

Torsional behavior of a new dumbbell-shaped concrete-filled steel tubes

This paper presents the first study of its kind on the torsional moment behavior of a new dumbbell-shape concrete-filled steel tube (DCFST) system. Experiments were conducted to investigate the effect of the dimensions of the web connecting the two circular CFSTs, in terms of its width-to-diameter (b/D) and its minimum depth-to-diameter (h/D) ratios, on torsional strength (Tu). Torsion tests were also conducted on circular CFSTs (CCFSTs), on hollow tubes and on plain concrete, as control specimens. It was shown that Tu of DCFSTs ranged from 1.3 to 2.2 that of the CCFST, depending on (b/D) and (h/D) ratios. Increasing (b/D) from 0.31 to 0.54 resulted in only 7% increase in Tu. However, a further increase from 0.54 to 1.0 resulted in an additional 31% increase in Tu. The effect of (h/D) on Tu was more pronounced at higher (b/D) ratios. In general, increasing the web width appears to be more effective than web height. A rigorous nonlinear finite element model was developed and a simple mechanics-based design equation have been proposed to predict Tu of CCFSTs and DCFSTs and resulted in an average predicted-to-experimental Tu of 0.98.

Web crippling study of rivet fastened rectangular hollow flange channel beams with flanges fastened to supports

Thin-walled steel hollow flange channel beams are commonly used as joists and bearers in various flooring systems in buildings. A new rivet fastened rectangular hollow flange channel beam was proposed using an intermittently rivet fastening process as an alternative to welded beams. This flexible fastening process allows rectangular hollow flange channel beams to have greater section optimisation, by configuring web and flange widths and thicknesses. In the industrial applications of rectangular hollow flange channel beams as flooring, roofing or modular building systems, their flanges will be fastened to supports, which will provide increased capacities. However, no research has been conducted to investigate the web crippling capacities of rectangular hollow flange channel beams with flanges fastened to supports under two-flange load cases. Therefore, an experimental study was conducted to investigate the web crippling behaviour and capacities of rectangular hollow flange channel beams based on the new American Iron and Steel Institute S909 standard test method. The web crippling capacities were compared with the predictions from the design equations in Australia/New Zealand Standard 4600 and American Iron and Steel Institute S100 to determine their accuracy in predicting the web crippling capacities of rectangular hollow flange channel beams. Test results showed that these design equations are considerably conservative for the end two-flange load case while being unconservative for the interior two-flange load case. New equations are proposed to determine the web crippling capacities of rectangular hollow flange channel beams with flanges fastened to supports. Test results showed that web crippling capacities increased by 78% and 65% on average for the end two-flange and interior two-flange load cases when flanges were fastened to supports. This article presents the details of this web crippling experimental study of rectangular hollow flange channel beam sections and the results.

Residual Winding Stresses Due to Spatial Web Thickness Variation

At the end of roll-to-roll (R2R) manufacturing process machines, the web substrate must be wound into rolls. Winding is the only means known to store and protect vast lengths of very thin webs for subsequent processing. Web thickness variation in wound rolls is a root cause of large manufacturing loss due to residual stress-related defects. Minute thickness variations down the length and across the web width can induce large residual stress variations and defects within the roll. Winding models allow the exploration of winding residual stresses whose variation has been affected by web thickness or coating imperfections. Knowledge of these stresses is used to mitigate manufacturing defects. Spot web thickness sensors are employed in R2R process lines that scan over the web width while the web is moving downstream through the process machine. Spatially, this provides a measure of web thickness in a zig-zag pattern. During manufacturing, the thickness variation is used as a control feedback parameter to manipulate a forming or coating die lip to reduce the web or coated web thickness variation. The thickness variation acceptable in process may be very different than that which is acceptable based on the residual stresses in the wound roll. It will be determined whether the thickness test data captured spatially for process feedback are sufficient to characterize the residual stresses in the wound roll. A winding model will be developed and verified that is used to characterize these residual stresses.