Showing papers on "Portal frame published in 2017"

Nonlinear piezoelectric vibration energy harvesting from a portal frame with two-to-one internal resonance

Abstract: In the few decades, the study of electro-mechanical systems which are capable to extract energy from an operating system in the environment has been of most importance. In this work, we present the extraction of energy from a simple portal frame structure excited by a harmonic force, where the energy harvesting is computed by using of a nonlinear piezoelectric material. The dynamical response of the system is examined, when there is 2:1 internal resonance between the symmetric and the sway mode, resulting the saturation phenomenon and vibration energy transfer between the symmetric (vertical) mode and the horizontal (sway) mode. An evaluation of the energy available for harvesting, in each of the considered modes, is computed.

Vibration Analysis and Development of an Ultrasonic Elliptical Vibration Tool Based on a Portal Frame Structure

Abstract: An ultrasonic elliptical vibration tool utilizing the coupled resonant vibration modes is the key component in the elliptical vibration cutting/texturing process, which has been successfully applied to ultra-precision machining and surface texturing. In this paper, an analytical approach is proposed to analyze the resonant frequency and mode shapes of the ultrasonic elliptical vibration tool. A new design of ultrasonic elliptical vibration tool based on a portal frame structure is presented and analyzed using the proposed model. The model assumes Euler-Bernoulli beams and utilizes the transfer matrix technique to reduce the order of the system to only six variables. The model can be utilized to provide a systematic approach for an optimal design and be extended to dynamic analysis of the tool for study of machine-tool dynamics. Finite element simulation results as well as experimental data based on the prototype design are presented to verify the model. An application of the proposed tool is also demonstrated in machining micro/nano-structured surfaces for structural coloration.

Structural Dynamic Investigation of Frame Structure with Bolted Joints

Abstract: Frame structure is widely used in many engineering structures. Besides, vibrational problem is one of the main challenges in industry. Bolted joints are commonly used in industry to connect two or more mechanical parts and it plays a significant role in the dynamics characteristic of the structure. This study aims to perform a model updating procedure on a portal frame structure which consists of bolted joints. Modal parameters such as the natural frequencies, mode shapes and damping ratios are gathered through finite element analysis (FEA) and experimental modal analysis (EMA). Frame structure is set to be fixed-free boundary condition and equivalence of nodes is performed at the area of bolted joints. Correlation between these two sets of data is carried out. With the selected parameters identified to perform model updating on the structure by using sensitivity analysis, the discrepancies in natural frequencies were reduced between FEA and EMA.

Experimental–numerical investigation on the seismic behaviour of moment-resisting timber frames with densified veneer woodreinforced timber joints and expanded tube fasteners

Abstract: Summary This paper investigates the seismic behaviour of moment-resisting timber frames with beam-column joints fastened with expanded tubes and reinforced with densified veneer wood. Laboratory experiments are carried out on single joints to investigate the cyclic behaviour and, more specifically, the impairment of strength, the ductility ratio and the equivalent viscous damping ratio. A phenomenological numerical model is proposed, where the beams and columns are schematized using linear-elastic beam elements, and the joints with non-linear hysteretic spring calibrated on the results of the experimental tests. The model is used to analyse some representative moment-transmitting structures characterised by different number of bays and storeys. After an estimation of the lateral load-carrying capacity using a pushover analysis, the numerical model is used to estimate the behaviour factor. An incremental dynamic analysis is performed using a set of accelerograms spectrum consistent with a chosen design spectrum. The analyses lead to an estimation of the behaviour factor of 3 and 6 for a portal frame and a five-storey, three-bay frame, respectively, which confirms the highly dissipative behaviour of this kind of moment connection. Copyright © 2017 John Wiley & Sons, Ltd.

Experimental Tests on a Dowel-Type Timber Connection and Validation of Numerical Models

Abstract: This paper examines the dynamic behaviour of timber framed buildings under wind and dynamic loads, focusing on the role of connections being experimentally tested. The main aim of this manuscript is to analyze the in-service dynamic behaviour of a semi-rigid moment-resisting dowel-type connection between timber beam and column. For this purpose, two laboratory tests have been performed, the first on a connection and another one on a portal frame. The results are used to validate a numerical model of the simple portal frame, analyzed in OpenSees. The obtained relationships are also discussed and compared with Eurocode rules. The main result is that the joint stiffness is calculated through the Eurocode (EC) formulation underestimates the experimental one. A mutual agreement is obtained between the numerical model, validated from the experimental stiffness value for the connections, and the experimental results on the portal frame.

Cyclic tests of steel plate shear walls using box‐shape vertical boundary elements with or without infill concrete

Abstract: Summary The steel plate shear wall (SPSW) is an effective lateral force resisting system in which unstiffened steel infill plates are connected to the horizontal and vertical boundary elements (VBEs) on all sides of the plates. The boundary elements must be designed to resist the tension field force of the infill panels. When the VBEs are made from a steel box section, the flange of each box VBE connected with the infill panels can be pulled out-of-plane by significant panel forces, called pull-out action. This study investigates capacity design methods for box VBEs in SPSWs. Simplified fixed beam and portal frame models aim to estimate the pull-out responses of the flange of the box sections with and without infill concrete, respectively. In this study, cyclic tests of three full-scale two-story SPSWs using box VBEs with or without the infill concrete are conducted. Inelastic pushover analyses of the finite element models are conducted. The tests and analytical results confirm that the proposed design methods, which aimed to prevent the full yield of the flange under the pull-out action, are applicable. Furthermore, the test and analytical results suggest that the initial yielding of the flange of box VBEs under the collective effects of the pull-out action on the flange, the gravity load, and the sway action on the SPSW represents a local yielding. A strict prohibition of the initial yielding on the flange under the aforementioned collective effects is not recommended for pursuing a cost-effective design. Copyright © 2017 John Wiley & Sons, Ltd.

Seismic Performance of Steel Frames with Semirigid Connections

Abstract: The nonlinear stiffness matrix method was incorporated to investigate the structural performance of steel portal frames with semirigid connections. A portal frame with unstiffened extended end-plate connection was designed to demonstrate the adequacy of the proposed method. Besides, the seismic performance of steel portal frames with semirigid connections was investigated through time history analysis where kinematic hysteresis model was assigned to semirigid connections to account for energy dissipation and unloading stiffness. Based on the results of the study, it was found that generally semirigid connections influenced the force distribution which resulted in the decrease in base shear and lighter frame compared to the rigid one. The results also indicated that there was no direct relationship between maximum displacement at the top and connection stiffness in high-rise frames.

Optimum design of cold-formed steel portal frame buildings including joint effects and secondary members

Abstract: In steel portal frames, cold-formed steel channel sections are increasingly used as the primary framing components, in addition to the secondary members e.g. purlins and side rails. For such framing systems, the stiffness of the joints at the eaves and apex affects the bending moment distribution, as well as the frame deflections. This paper investigates the influence of two joint configurations having full rigidity and semi-rigidity, respectively, on the optimum design of cold-formed steel portal frames. A real-coded genetic algorithm is used to search for the most cost-effective design. It is shown that through incorporating joint effects explicitly into the design process, a more appropriate balance between the joints and the member properties can be obtained, thus optimizing material use. The study then investigates the effect of secondary members on the optimum design. It is shown that incorporating the secondary members is important for portal frames having spans shorter than 12 m. For example, for a frame spacing less than 6 m, the material cost of the primary members can be reduced by up to 15%.

Servosyn of numerical control sawing machine feeds imperial portal frame device

Abstract: The utility model provides a servosyn of numerical control sawing machine feeds imperial portal frame device belongs to the equipment that saw cuts technical field. Present sawing machine inefficiency, the low scheduling problem of precision have been solved to it. This imperial portal frame device includes the portal frame and sets up the unit head on the portal frame, the both sides of sawing machine lathe bed all are provided with linear guide, two of portal frame is erect respectively on corresponding linear guide and can be followed linear guide back and forth movement, linear guide's the outside still all corresponds and is provided with the rack, rack and linear guide all set up along the work piece direction of feed, two of portal frame all is provided with and corresponds the power drive mechanism that side linear guide and rack correspond, this power drive mechanism includes the gear, feed speed reducer and vertical servo motor. Two sets of servo synchro -driven about this portal frame adopts, each unit head can realize respectively to there being solitary servo that the accuracy of X axle, Y axle is fed and is fixed a position, guarantees the stepless speed regulation and the high accuracy size location of feed.

The Effect of Element Types on Force Analogy Method Analysis

Abstract: In this study, the seismic performance of a 2D portal frame subjected to the recorded seismic ground motions of the Northridge 1994 earthquake was evaluated by the force analogy method (FAM) with different element types. To increase the accuracy of FAM, Timoshenko (TS) elements were employed instead of the classical Euler Bernoulli (EB) elements, to revert the shear deformations that are neglected in EB elements. To perform evaluation, the same material and section properties were considered and the same portal frame was analyzed with different element lengths, from 0.5 to 7.0 m in 0.5 m steps.

Strength and stiffness of cold-formed steel portal frame joints using quasi-static finite element analysis

Abstract: This paper describes a quasi-static finite element analysis, which uses the explicit integration method, of the apex joint of a cold-formed steel portal frame. Such cold-formed steel joints are semi-rigid as a result of bolt-hole elongation. Furthermore, the channel-sections that are being connected have a reduced moment capacity as a result of a bimoment. In the finite element model described, the bolt-holes and bolt shanks are all physically modelled, with contact defined between them. The force-displacement curves obtained from the quasi-static analysis are shown to be similar to those of the experimental test results, both in terms of stiffness as well as failure load. It is demonstrated that quasi-static finite element analysis can be used to predict the behavior of cold-formed steel portal frame joints and overcome convergence issues experienced in static finite element analysis.

Duplex position laser beam machining device

Abstract: The utility model discloses a duplex position laser beam machining device, including the base, the laser cutting head is fixed in the portal frame on the base, in the crossbeam of portal frame set up side by side down in first workstation and second workstation on the base for the first workstation of separately -driven and second workstation be along a Y axle subassembly and the 2nd Y axle subassembly of the motion of Y axle orientation, is used for driving laser cutting head along the Z axle subassembly of Z axle orientation motion, and set up in be used for driving the X axle subassembly of Z axle subassembly along the motion of X axle direction on the crossbeam of portal frame. Through adopting the double workbench mode of processing in turn, realized carrying on in succession laser cutting, improved production efficiency, workstation linear motion's mode has improved positioning accuracy and machining precision through adopting the portal frame to fix.

Vehicle gabarit size detection appearance

Abstract: The utility model discloses a vehicle gabarit size detection appearance, the utility model relates to measure technical field, indicate the used vehicle gabarit size detection equipment of department such as a policeman vehicle administrative institute, vehicle test station especially. Including portal frame, laser scanner group, photoelectric sensor, electrical apparatus case, dot -matrix display screen and system computer. The portal frame includes preceding portal frame and back portal frame. Laser scanner group comprises left scanner, right scanner and preceding scanner. Wherein left and right scanner is installed in the crossbeam both ends of preceding portal frame, the scanning plane coincidence to it is perpendicular with the vehicle travel direction, preceding scanner is installed in the crossbeam middle section of back portal frame, and scanning plane is parallel with the vehicle travel direction. The utility model discloses realizing measuring process automation and going on, the measuring speed is fast, it is few influenced by external light, the good reliability, and structural design is succinct, simple to operate.

Plank cutting all -in -one that punches

Abstract: The utility model discloses a plank cutting all -in -one that punches, including be equipped with the workstation the frame, locate positioning mechanism, drill bit, the cutterbar on the workstation and stride the portal frame of locating in the frame, on two portal frames are located to drill bit and cutterbar branch, still including the driving gantry frame along the Y axle running gear of the vertical walking of frame, along the X axle running gear of the horizontal walking of frame and locate X axle running gear and go up the Z axle running gear who walks perpendicularly. Compared with the prior art, the beneficial effects of the utility model are that: the location is accomplished promptly in proper order to pan feeding, measures the location when having eliminated manual operation and time of changing the work piece, and the location uses right side baffle and back side shield for the location benchmark, through the cylinder left side push plate of the drive location that side push plate accomplished the plank before and, the utility model discloses realize an equipment, accomplish two kinds of functions of drilling and cutting panel simultaneously to can carry out corresponding adjustment according to actual board material size.

Automatic rivet stapling machine

Abstract: The utility model provides an automatic rivet stapling machine, includes the punch press, installs the stamping die on the punch press, lies in the workstation in punch press the place ahead, installs the portal frame on the workstation, sets up the rivet pick -and -place subassembly on the portal frame, installs on the workstation and lie in Y axle conveying mechanism and symmetry between two landing legs of portal frame to set up and supply defeated mechanisms in Y axle conveying mechanism both sides and two rivets lieing in portal frame the place ahead, the utility model relates to an ability automatic feed has improved production efficiency, has reduced riveting workman's intensity of labour.

Bifurcation Analysis and Chaos Control of a Fractional Order Portal Frame with Nonideal Loading Using Adaptive Sliding Mode Control

Abstract: We investigate the chaotic oscillations in a fractional order model of a portal frame with nonideal loading. The bifurcation of the fractional order portal frame system for parameters and fractional orders are investigated. Bicoherence analysis shows the existence of quadratic nonlinearities. Fractional order adaptive sliding mode controllers are designed to suppress the chaotic oscillations with uncertain parameters. Power efficiency analysis of the FPGA implemented control scheme shows the maximum power utilization in the fractional order showing the largest Lyapunov exponent.

Optical fiber laser cutter

Abstract: The utility model discloses an optical fiber laser cutter, including main frame, the auxiliary rack who sets up at the main frame front end, install the portal frame on the main frame and the head is penetrated in the cutting of installing on the portal frame, still includes two workstations, portal frame slidable mounting is equipped with longmen slide rail in the both sides upper end of main frame on the main frame, drive the portal frame through longmen gear motor driving gantry slide track seat and slide on the slide rail of longmen, the protrusion is equipped with a plurality of rail brackets and time rail brackets of going up on the relative both sides wall in main frame and auxiliary rack, last, install on the rail brackets down, a lower guide rail, last, a lower guide rail, slidable mounting is last for two workstations difference, on the lower guideway, carry out staggered floor automatic switching through two workstations, two workstation automatic switching, one one is advanced to get the material in the circulation, the effectual simplex of having solved is made bench material to get material down time long, the problem that rate of equipment utilization with high costs is low, improving equipment utilization rates, which saves cost

Modular steel structure house

Abstract: A modular steel structure house comprises a plurality of module units which are spliced with one another. Each module unit comprises a steel structure framework, an outer wall, an inner wall, a floor slab, an electrical system and a water supply and drainage system, wherein the steel structure framework comprises a bottom framework, a top framework and a plurality of portal frames arranged in parallel. Each portal frame comprises portal frame stand columns and a portal frame cross beam, wherein the two ends of the portal frame cross beam are welded to the upper ends of the two portal frame stand columns; the lower ends of the portal frame stand columns are welded to bottom framework side beams; and an upper mounting base is arranged on the top of each portal frame stand column, a butt joint area is formed in the middle of each upper mounting base, and mounting lugs are formed on the two sides of each upper mounting base. A top framework side beam is arranged between the upper ends of every two adjacent portal frame stand columns on the same side. The two ends of each top framework side beam are connected with the corresponding upper mounting bases through bolts. The top framework side beams and the portal frame cross beams form the top frameworks. Each outer wall comprises an outer wallboard and a suspension part, and the outer wall is fixed to the corresponding steel structure framework through the suspension part. According to the modular steel structure house, lightweight design is achieved, the structural strength is high, house splicing can be achieved, and construction is convenient.

Unloading pile up neatly system

Abstract: The utility model relates to an unloading pile up neatly system in automatic control field, including fixing the portal frame on ground, set up roller conveyor and material pallet in the portal frame below, be provided with the manipulator on the portal frame, mechanical handbag draws together the support and fixes the sucking disc device in the support below, install transverse feeding mechanism and longitudinal feed mechanism on the support, cooperation transverse feeding mechanism installs rack no. 1 on the portal frame, and be provided with rack two, transverse feeding mechanism to cooperation longitudinal feed mechanism and longitudinal feed mechanism is driven by actuating mechanism respectively on the support, the utility model discloses a can be extensive be applied to during the current production makes is carried out the multiple spot to panel and is snatched, realizes the automation of unloading pile up neatly, improves work efficiency, reduces intensity of labour, easily operation, has reduced manufacturing cost.

Stone material board perforating device

Abstract: The utility model relates to a stone material preparation technical field especially relates to a stone material board perforating device, including portal frame, cylinder, workstation, dust removal motor, dust removal box and have the motor of drill bit, the cylinder is fixed on the motor frame, the motor with vertical guide rail sliding fit on the motor frame, the piston rod of cylinder with the lateral wall of motor is connected, the motor frame is in with the setting the slide rail sliding fit on portal frame upper portion, have the lead screw cover on the motor frame, the lead screw cover is in with the setting lead screw cooperation on the portal frame, the one end of lead screw has the hand wheel, the workstation sets up the portal frame lower part, have a plurality of through -hole on the workstation, the dust removal box sets up the lower part of workstation, the inside packing of dust removal case had the filter pulp, dust removal motor installs on the dust removal box. This device simple structure, the precision of driling has been guaranteed to the effectual clear waste material that produces.

Optimal fire design of steel tapered portal frames

Abstract: The development of new and valuable conceptual design concepts based on structural optimization results is the global aim of the presented research in order to assist the industry in economical fire design of steel tapered portal frames. In order to find optimal configurations regarding the life cycle of the structure, a complex, reliability based structural optimization framework has been developed for tapered portal frame structures. Due to the high nonlinearity and discrete nature of the optimality problem, Genetic Algorithm is invoked to find optimal solutions according to the objective function in with the probability of failure is evaluated using First Order Reliability Method. The applied heuristic algorithm ensures that a number of possible alternatives are analysed during the design process. Based on evaluation of the results of a parametric study, new conceptual design concepts and recommendations are developed and presented for steel tapered portal frames used as storage hall related to optimal structural safety, common design practice and optimal structural fire design.

Hydraulic portal crane

Abstract: A hydraulic portal crane comprises a portal frame structure. A cart walking device is arranged at the bottom of the portal frame structure. A cab is arranged in the middle of the portal frame structure. Oil cylinder jacking mechanisms are arranged on the two sides of the portal frame structure. A lifting appliance translation frame, a lifting appliance rotating frame and a lifting appliance turnover frame are arranged at the top of each oil cylinder jacking mechanism. Each lifting appliance turnover frame is hinged to the top of the corresponding oil cylinder jacking mechanism. The tops of the two lifting appliance turnover frames are connected through a sliding cross beam. The translation frames are arranged on the sliding cross beam. Each lifting appliance rotating frame is arranged below the corresponding lifting appliance translation frame and provided with a lock device. According to the hydraulic portal crane, all operation tasks of containers in a train freight transport yard can be completed, and for example, the containers can be unloaded from a train, can be mounted on a vehicle and can be placed on the ground to be stacked; the containers can be turned over by a certain angle, and loading and unloading of bulk materials are completed; and the hydraulic portal crane is small in size and small in weight.

The optimisation of web-tapered portal frame buildings

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