Vertical Flanges Research Articles

A new hold-down device for seismic applications in CLT buildings: Design, testing, analytical and numerical assessment

An hold-down device was designed and tested experimentally for seismic applications (Seismic Hold-Down, SHD). The magnitude of axial strength as well as the up-lift displacement capacity is mainly oriented to cross-laminated-timber (CLT) buildings with medium-to-high ductility. There is consensus in the design practice of hold-down devices for promoting, as dissipative mechanism, flexural yielding of the dowel-type connectors (e.g. nails, screws) combined to timber’s embedment. Few are the applications aiming at hold-down’s optimization as it emerges from up-to-date literature review. In this framework, SHD was conceived such that tension break-out of steel was promoted at a reduced segment (fuse) of the vertical flange. In the context of capacity design, a convenient overstrength was assumed for other failure mechanisms, e.g. anchor’s pullout, laterally-loaded steel-to-timber connection, shear-plug of timber. The mechanical response under axial load was consistently predicted by an application of the component method, i.e. global stiffness and strength were analytically-derived using simplified series of non-linear mechanical springs. Three-dimensional finite elements model was employed to investigate buckling of the fuse which might occur, during cycles, when up-lift displacement is recovering. In practical circumstances, it is recommend to design SHD devices of a CLT wall similarly to diagonal elements of steel bracings, i.e. neglecting the contribution of the compressed element. Finally, SHD is compared to traditionally-designed hold-down, which mostly dissipates (and fails) at steel-to-timber connection. Overall hysteretic response is somehow similar, although the inelastic mechanisms involved are different. For example, both the devices show pinching during cycles which for SHD is mainly caused by buckling of the fuse while, for traditional hold-down, is dominated by timber’s embedment.

A parametric analysis of the performance of a horizontal axis tidal current turbine for improving flow-converging effect

This paper proposed a research method for secondary design and parametric analysis of the contraction section of the shroud to improve the flow-gathering effect of horizontal axis tidal current turbines. By comparing the velocity ratio, drag coefficient, and flow field stability of the nine different shroud profile types, a conclusion was drawn that the hydrodynamic performance of the exponential (Type-A) shroud is best. On this basis, the primary parametric analysis of the A profile type shroud is carried out by changing the contraction ratio of the shroud's contraction section to divide the profile into three parts. The results show that the vertical flange inhibits the flow-gathering effect of the shroud, so the secondary parametric analysis is proceeded by removing the flange and changing the flange inclination angle, respectively. At the contraction ratio of 6/8, the flow-gathering effect of each shroud is best, among which the hydrodynamic performance of Type-ABL-6-85° shroud with the flange inclination angle of 85° is best. The maximum power coefficient (Cpmax) is 43.20%, which is 31.59% higher than that with Type-A shroud when the tip speed ratio is 1.5. Therefore, it can be considered that the combined profile type of the shroud contraction section has a better flow-gathering effect than the single profile type.

Experimental studies on incremental hole flanging of steel sheets

ABSTRACTIncremental Hole-Flanging (IHF) process has various applications in rapid prototyping and low volume production of conical and vertical flanges in sheet metal parts. Therefore, understanding mechanics and failure strategies in IHF is very important for successful forming without cracks. In this paper, Deep Drawing (DD) steel blanks with pre-cut hole of 40 and 70 mm diameter are used for multistage conical hole flanging. Conical hole flanges are formed on CNC milling machine with starting angle 60° to final angle 90° with an increment of 10°. The experimental results showed a crack at 80° flange angle with the blank of 40 mm pre-cut hole. The blank with 70 mm-pre-cut hole has no such crack behaviour even at 90° flange angle. The paper also discusses the variation of flange height, surface roughness and forming forces in IHF of DD steel sheets.

Determination of an adequate geometry of the flanged hole to perform formed threads

In this work, the flanged hole is adopted as a potential solution to increase the number of formed threads in the case of sheet metal part. To achieve an adequate initial tap hole for tapping process, the final shape of the flanged hole was analyzed by 2D finite element (FE) simulations. An adequate range of the clearance j between the die and the punch of the hole-flanging process was identified for which formed threads are performed on a vertical flange with more substantial and uniform thickness as well as an important height. To ensure that the selected flange is free from fracture, 3D FE model was developed using Gurson-Tvergaard-Needleman coupled approach. Experiments were carried out in order to validate the numerical results and to analyze the geometry of formed threads performed on the selected flanged hole and the drilled hole.

매입된 석션앵커의 인발력에 대한 분석적 매개변수의 연구

The Embedded Suction Anchor (ESA) is a type of permanent offshore foundation that is installed by a suction pile. To increase the loading capacity against pullout, three wings (vertical flanges) are attached along the circumference at 120 degrees apart. Analytical parametric study using the proposed analytical solution method has been conducted to identify the effects of several parameters that are thought to influence the behavior of ESAs. The analysis results show that the pullout capacity increases as the anchor depth and the soil strength increase, and decreases as the load inclination angle increases. The anchor having square projectional area and being pulled horizontally at the middle of its length provides the highest pullout capacity.

Effect of vertical flange stiffener on ductility of slotted web exclusive connection on (I)-shape profiles through experimental investigation

The separation of flange from beam web at slotted web connection improves many weaknesses of connection. Increasing ductility and elimination of the shear force present in beam flanges are benefits of this connection. In this article, the seismic behavior of this connection on IPE cross-sections is investigated with analytical methods and experimental testing, while considering effective factors in design. Using vertical flange stiffener on this connection is strongly impressive in improvement behavior of this connection. Considering design measures, results show no strength reduction in this part, compared to its non-slotted counterpart, and indicate lower strain gradient in beam flange welds. Performance comparisons on experimental study are made based on the total rotation, maximum resistance and energy dissipation of the specimens. Suitable ductility at this connection show that this connection stands in special moment connection class. More participation of panel zone in earthquake energy absorption reduces the total ductility of this connection and its maximum resistance.

Flexural capacity of plate girders with very slender corrugated webs

Corrugated web beams in industrial buildings commonly have a very slender web, which can induce a brittle vertical flange buckling. Full-scale corrugated web beams were tested, in order to verify the flexural capacity and the limit state of the vertical flange buckling of corrugated web beams with very slender webs. Flexural behavior and the effect of the residual stress were explored. All specimens failed due to vertical flange buckling after flange yielding at the mid-span of specimens. Corrugated web beams in the test had the flexural strength 6~17% larger than the flexural capacities from DASt-Ri 015. Based on the test results, a modified slenderness ratio limit, modified to 1.5 times that of the conventional value, was suggested. Numerical analysis with various parameters was performed to verify the accuracy of the modified slenderness ratio limit.

Effect of Initial Thickness to Cut End Deformation of Hat Shape Channel Steel by Roll Forming

A hat channel, also called a furring channel, is a channel with a bottom horizontal web and two vertical flanges, as well as an outward lip that is fabricated by roll forming. When the channel is cut off at a specified length, the edge of the product will change due to the release of residual stress, and this change is generally called cut end deformation. The cut end deformation of channel steel was investigated via experiment and three-dimensional finite-element simulation. The effect of initial thickness on the cut end deformation of hat channel steel was studied. For hat channel steel, the deformations at the front end and back end increase when the sheet metal thickness increases. However, the influence of initial thickness on the cut end deformation of hat-shape channel steel is small.

Bending Strength of a Horizontally Curved Composite I-Girder Bridge

AbstractHorizontally curved I-girders are subjected to combined vertical bending and torsion under gravity loads alone. The torsional behavior of open I-shaped girders is commonly and conveniently transformed to self-equilibrating lateral bending of flanges. The interaction of vertical bending and lateral flange bending reduces the vertical moment–carrying capacity of the section. The interaction equations for predicting the nominal bending strength of horizontally curved I-girders of compact-flange sections subjected to vertical moment and torsion have been derived. Singly symmetric composite and noncomposite I-shaped cross sections in the positive and negative moment zones, respectively, are considered. These strength criteria are based purely on the static equilibrium of the cross section with no secondary amplification considered. The limitations and applicability of the derived equations toward the design use are demonstrated and analyzed.

The skull of the Upper Cretaceous snake Dinilysia patagonica Smith-Woodward, 1901, and its phylogenetic position revisited

The cranial anatomy of Dinilysia patagonica, a terrestrial snake from the Upper Cretaceous of Argentina, is redescribed and illustrated, based on high-resolution X-ray computed tomography and better preparations made on previously known specimens, including the holotype. Previously unreported characters reinforce the intriguing mosaic nature of the skull of Dinilysia, with a suite of plesiomorphic and apomorphic characters with respect to extant snakes. Newly recognized plesiomorphies are the absence of the medial vertical flange of the nasal, lateral position of the prefrontal, lizard-like contact between vomer and palatine, floor of the recessus scalae tympani formed by the basioccipital, posterolateral corners of the basisphenoid strongly ventrolaterally projected, and absence of a medial parietal pillar separating the telencephalon and mesencephalon, amongst others. We also reinterpreted the structures forming the otic region of Dinilysia, confirming the presence of a crista circumfenestralis, which represents an important derived ophidian synapomorphy. Both plesiomorphic and apomorphic traits of Dinilysia are treated in detail and illustrated accordingly. Results of a phylogenetic analysis support a basal position of Dinilysia, as the sister-taxon to all extant snakes. The fossil taxa Yurlunggur, Haasiophis, Eupodophis, Pachyrhachis, and Wonambi appear as derived snakes nested within the extant clade Alethinophidia, as stem-taxa to the crown-clade Macrostomata. The hypothesis of a sister-group relationship between Dinilysia and Najash rionegrina, as suggested by some authors, is rejected by the results of our analysis.

Kinematics Simulation of Vertical Flange Lathe with Double Machining Tools Based on Virtual Prototype Technology

To study the kinematic characteristics of a new designed flange vertical lathe with double machining tools, a virtual prototype model was developed in ADAMS with the help of PRO/E and MechPro, a seamless interface program between both mentioned software. And kinematic and dynamic simulations were carried out. The results of the simulations are consistent with the reality which states that the model was created correctly and the simulations were reliable.

A Study on Flange Lathe of Double-Tool Holder Based on Optimization Design Method of FE

With the optimization design method of FE,the FE model of vertical flange lathe beam of double-tool holder was established,the sensitivity analysis of dynamic performance for the machine tool was performed based on presented modal analysis and probability analysis.The influence rules of the first four natural frequencies affected by the design parameters of the lathe beam were confirmed and the weaknesses of it were indicated as well.Then, the structure of the lathe beam was optimized.As a result ,the dynamic performances of the lathe beam are improved and it offers the basis for the optimization design of the other lathe parts.

Embedded Suction Anchors for Mooring of a Floating Breakwater

A floating breakwater was built in Southern Korea. Four separate floating breakwater units were moored to ten deeply buried embedded suction anchors. The embedded suction anchor is a type of permanent offshore foundation installed by a suction pile. The cross section of the embedded suction anchor is circular, with its diameter being equal to that of the suction pile that is used to drive it into the seafloor. Vertical flanges are typically added along the circumference to increase its resistance. Determination of the loading capacity and the dimensions of embedded suction anchors are described. Details of the construction and installation of embedded suction anchors, as well as the field proof test results are also discussed. A total of ten steel embedded suction anchors were manufactured and installed successfully. Installation of embedded suction anchors was accomplished with a suction pile attached to its top. Subsequent proof tests validated the design loading capacity of embedded suction anchors. A floating breakwater consisted of four separate units was constructed. Initially, embedded deadweight concrete blocks were considered to moor the floating breakwater units. Later, however, embedded suction anchors replaced the concrete block anchors due to numerous environmental constraints. Each floating unit was anchored with four embedded suction anchors. Field proof tests indicate that the embedded suction anchors can provide necessary resistance against the anticipated wind and wave forces.

Development of a Mechanism of Pipe-Surface Inspection Robot

Inspection of industrial piping is a well-known and highly practical application of robotic technology. The present study examines a mechanism that allows a pipe inspection robot to move along the outside of a pipe. Robots especially designed to inspect the surface of piping have recently been realized by some companies, and are in practical use as mechanical piping inspection devices in various plants. These robots are equipped with ultrasonic diagnostic equipment that can measure the thickness of the pipe along its surface. However, they are able to move by manual operation only. Such robots cannot be applied to pipes with flanges and valves, etc. In this paper, we have designed a mechanism that enables robots to traverse flanges, rise along vertical flanges, and move along the underside of the piping. The proposed robots are composed of three connected units. Our robots move by means of magnetic elements (magnetic wheels or electromagnets).

비틀림 변형 최소화를 위한 전자레인지 도어 프레임의 형상 최적설계

When one opens the door of a microwave oven during its operation, twisting deformation of the door occurs, which may cause leakage of microwave through the gap between the door and the front plate. A numerical optimization is implemented to minimize the gap by maximizing twisting stiffness of the door of the oven. Design variables are defined, which describe the shape of the bead in the horizontal and vertical flanges of the door frame. To minimize the twisting deformation, Two optimal design problems to find shapes of the bead in the flange are established. The problems are solved by a numerical optimization technique, their results being evaluated.

523 配管表面検査ロボットの開発 : 垂直配管移動と水平配管底部におけるフランジ越えの自律制御(学生賞IV)

523 配管表面検査ロボットの開発 : 垂直配管移動と水平配管底部におけるフランジ越えの自律制御(学生賞IV)

A new taxon of helodermatid-like lizard from the Albian–Cenomanian of Utah

ABSTRACT A new platynotan lizard, Primaderma nessovi, gen. et sp. nov., from the Mussentuchit Local Fauna, Cedar Mountain Formation (Albian–Cenomanian) of Utah is unique in having a premaxillary process of the maxilla that forms a vertical flange and fine serrations on anterior and posterior edges of the maxillary teeth. Primaderma is the oldest-known terrestrial platynotan and phylogenetic analysis indicates that it is a member of Monstersauria, a clade of helodermatid-like platynotans. The teeth of Primaderma show several derived platynotan characteristics, but do not possess venom grooves. The distribution of this trait in fossil taxa is reassessed. Although a North American origin of helodermatid-like platynotans is likely, it is possible that Primaderma represents another example of an Asian influence on the North American Cretaceous fauna. As with similar taxa, Primaderma was likely highly predaceous, presumably taking vertebrate prey and it appears that helodermatid-like lizards have changed very little since the Albian–Cenomanian.

船用仕切弁の三次元応力解析

The geometrical features of marine gate valves have been specified in JIS-F. Recently, they are going to be modified based on the International Standard (ISO) . The distances between two flange faces of the gate valves is shortened in the ISO Standards which may cause to reduce its structural rigidity.This paper presents the deformation characteristics of the marine gate valves in ISO standards which are analyzed by the three - dimensional finite element method. The analysis draws to, the following results:(1) Based on the deformation characteristics, the structure of the marine gate valve can be modelled by the composite structure consisting of the cylindrical and rectangular shells with flanges at each edge.(2) The bonnet flange considerably reduces the deformation of the valve body.(3) The performance for shutting off fluid flow, defined by Eq. (1) in this paper, of ISO valves is sperior to other gate valves, which are in the market in Japan and U.S.A., with size 2-24B(4) The ribs connecting the bonnet and vertical flanges effectively increase their structural rigidity.

Month in the Patent Office

To maintain liquid‐tightness in an integral wing fuel tank at the junction of the stringers 12, 13 and the bulkhead 10 forming the end wall of the tank, each stringer is divided into inner and outer portions 12, 13 respectively, the webs of the two portions being in alignment and bolted to a cylindrical connector 14 passing through a hole in the bulkhead, the stringer webs being disposed in vertical longitudinal slots 25, 29 in the connector which grips the bulkhead between a collar 24 and nut 22. Scaling washers 20, 21 bear against the bulkhead and the vertical flange 18 of an angle‐section member supporting the bulkhead. The stringer dangers are riveted to the wing skin 11 and ribs 16. During assembly the web of the outer stringer section 13 is first inserted in the slot 25 and bolted to the connector 14, and the latter with the ring 21 in pisition is then passed through the hole in the bulkhead and the nut 22 and ring 20 screwed into position, after which the inner stringer section 12 is inserted in the slot 29 and bolted to the connector 14.