Optimization of a Snap Through Spring for a Hydraulic Valve With Hysteresis Response Behavior

2019 ◽  
Author(s):  
Matthias Scherrer ◽  
Rudolf Scheidl ◽  
Bernhard Manhartsgruber
Keyword(s):  
Ritz Method ◽  
High Strength ◽  
Axial Direction ◽  
Approximate Solutions ◽  
Element Model ◽  
Lateral Force ◽  
Spring Steel ◽  
Nonlinear Buckling ◽  
Buckling Beam ◽  
Compact Design

Abstract The hydraulic binary counter requires switching valves with a hysteretic response. In this paper an elastic snap through element is studied as means for that. The concept is based on a buckling beam which is elastically supported in axial direction in order to adjust its buckling properties with moderate manufacturing precision and to assure a well defined snap through behavior. The elastic support is provided by a cantilever beam. A rigorous optimization is performed heading for a most compact and fatigue durable design which exhibits the required lateral force displacement characteristics. A genetic algorithm is used to find the global design optimum. The stress/displacement properties of each design variant are computed by a compact model of the snap through system. It is derived by a Ritz method to obtain approximate solutions of the nonlinear buckling beam behavior. Its validity is checked by a Finite Element model. A compact design is possible if high strength spring steel is used for the elastic elements.

scholarly journals The Stability of a Movable High-Strength Inverted-Triangular Steel Bridge

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Lei Gao ◽  
Linyue Bai ◽  
Kebin Jiang ◽  
Qiang Wang ◽  
Xiaohui He
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Performance Test ◽  
High Strength ◽  
Element Model ◽  
Elastic Stability ◽  
Load Test ◽  
Truss Structure ◽  
Steel Bridge ◽  
Nonlinear Buckling

The overall stability of a movable high-strength inverted-triangular steel bridge is worth studying because of its new truss structure. In this study, an approach was proposed based on the stiffness equivalence principle in which the inverted-triangle truss structure was modeled as a thin-walled triangular beam. On this basis, the calculation of the critical load of elastic stability of a movable high-strength inverted-triangular steel bridge with variable rigidity at both ends and locally uniformly distributed load was carried out based on the energy theory, which was in good agreement with existing theories. A material performance test at BS700 was carried out to establish the material properties, and then a finite element model of the bridge was established, the results of which were compared with those of the experimental load test, in order to verify the accuracy of the finite element model. Considering material nonlinearity and geometric nonlinearity, nonlinear buckling analysis of the bridge was conducted and the factors influencing the bridge’s ultimate bearing capacity were analyzed.

INLAND DURASPRING

Alloy Digest ◽  
1998 ◽  
Vol 47 (5) ◽  
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Tensile Properties ◽  
High Stress ◽  
High Strength ◽  
Spring Steel ◽  
Fatigue Properties ◽  
Light Truck ◽  
Suspension Systems ◽  
Spring Steels

Abstract Inland DuraSpring is a high-strength microalloyed spring steel for use in high stress coil springs for automobile and light truck suspension systems. This bar product offers significant improvements in tensile strength, fatigue properties, and fracture toughness compared to conventional spring steels. This datasheet provides information on composition, hardness, and tensile properties as well asfracture toughness and fatigue. Filing Code: SA-496. Producer or source: Ispat Inland Inc.

scholarly journals Internal Force on and Deformation of Steel Assembled Supporting Structure of Foundation Pit under Thermal Stress

2021 ◽  
Vol 11 (5) ◽  
pp. 2225
Author(s):  
Fu Wang ◽  
Guijun Shi ◽  
Wenbo Zhai ◽  
Bin Li ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Bending Moment ◽  
High Strength ◽  
Element Model ◽  
Internal Force ◽  
Foundation Pit ◽  
Dimensional Finite Element ◽  
Influence Of Temperature On ◽  
Scale Experiment ◽  
Three Dimensional Finite Element

The steel assembled support structure of a foundation pit can be assembled easily with high strength and recycling value. Steel’s performance is significantly affected by the surrounding temperature due to its temperature sensitivity. Here, a full-scale experiment was conducted to study the influence of temperature on the internal force and deformation of supporting structures, and a three-dimensional finite element model was established for comparative analysis. The test results showed that under the temperature effect, the deformation of the central retaining pile was composed of rigid rotation and flexural deformation, while the adjacent pile of central retaining pile only experienced flexural deformation. The stress on the retaining pile crown changed little, while more stress accumulated at the bottom. Compared with the crown beam and waist beam 2, the stress on waist beam 1 was significantly affected by the temperature and increased by about 0.70 MPa/°C. Meanwhile, the stress of the rigid panel was greatly affected by the temperature, increasing 78% and 82% when the temperature increased by 15 °C on rigid panel 1 and rigid panel 2, respectively. The comparative simulation results indicated that the bending moment and shear strength of pile 1 were markedly affected by the temperature, but pile 2 and pile 3 were basically stable. Lastly, as the temperature varied, waist beam 2 had the largest change in the deflection, followed by waist beam 1; the crown beam experienced the smallest change in the deflection.

scholarly journals Experimental and Numerical Investigation on the Perforation Resistance of Double-Layered Metal Shield under High-Velocity Impact of Armor-Piercing Projectiles

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 626
Author(s):  
Riccardo Scazzosi ◽  
Marco Giglio ◽  
Andrea Manes
Keyword(s):  
High Strength Steel ◽  
Steel Plate ◽  
Experimental Studies ◽  
Practical Interest ◽  
High Strength ◽  
Experimental Tests ◽  
Element Model ◽  
Transportation Systems ◽  
Metal Shield ◽  
Softening Parameter

In the case of protection of transportation systems, the optimization of the shield is of practical interest to reduce the weight of such components and thus increase the payload or reduce the fuel consumption. As far as metal shields are concerned, some investigations based on numerical simulations showed that a multi-layered configuration made of layers of different metals could be a promising solution to reduce the weight of the shield. However, only a few experimental studies on this subject are available. The aim of this study is therefore to discuss whether or not a monolithic shield can be substituted by a double-layered configuration manufactured from two different metals and if such a configuration can guarantee the same perforation resistance at a lower weight. In order to answer this question, the performance of a ballistic shield constituted of a layer of high-strength steel and a layer of an aluminum alloy impacted by an armor piercing projectile was investigated in experimental tests. Furthermore, an axisymmetric finite element model was developed. The effect of the strain rate hardening parameter C and the thermal softening parameter m of the Johnson–Cook constitutive model was investigated. The numerical model was used to understand the perforation process and the energy dissipation mechanism inside the target. It was found that if the high-strength steel plate is used as a front layer, the specific ballistic energy increases by 54% with respect to the monolithic high-strength steel plate. On the other hand, the specific ballistic energy decreases if the aluminum plate is used as the front layer.

scholarly journals Variational Methods for Glacier Mechanics Problems

1981 ◽  
Vol 27 (95) ◽  
pp. 19-24 ◽  
Author(s):  
Robert G. Oakberg
Keyword(s):  
Finite Element ◽  
Melting Point ◽  
Variational Principle ◽  
Finite Element Model ◽  
Related Problem ◽  
Cylindrical Channel ◽  
Direct Methods ◽  
Approximate Solutions ◽  
Element Model ◽  
Coordinate Functions

AbstractThe object of the research is to determine whether direct methods from the calculus of variations can provide convenient approximate solutions of complex problems in glacier mechanics. The Ritz technique is used to minimize an appropriate functional. Coordinate functions obtained from a finite-element model are combined with a coordinate function that is the solution of a related problem. The finite-element coordinate functions make localized adjustments to the related solution. Solutions of two sample problems are presented. An analysis of the closure of an intergranular vein in ice at the melting point is based upon a variational principle for velocities. An analysis of the flow of ice in a cylindrical channel is based upon a variational principle for stresses.

Free Vibrations of Thick, Complete Conical Shells of Revolution From a Three-Dimensional Theory

2005 ◽  
Vol 72 (5) ◽  
pp. 797-800 ◽  
Author(s):  
Jae-Hoon Kang ◽  
Arthur W. Leissa
Keyword(s):  
Ritz Method ◽  
Three Dimensional ◽  
Axial Direction ◽  
Free Vibrations ◽  
Mode Shapes ◽  
Vibration Frequencies ◽  
Shells Of Revolution ◽  
Dimensional Theory ◽  
Conical Shells ◽  
Cylindrical Coordinate

A three-dimensional (3D) method of analysis is presented for determining the free vibration frequencies and mode shapes of thick, complete (not truncated) conical shells of revolution in which the bottom edges are normal to the midsurface of the shells based upon the circular cylindrical coordinate system using the Ritz method. Comparisons are made between the frequencies and the corresponding mode shapes of the conical shells from the authors' former analysis with bottom edges parallel to the axial direction and the present analysis with the edges normal to shell midsurfaces.

Contrastive Study on Finite Element Models of High-Strength Pipelines Crossing Active Faults

2016 ◽  
Vol 850 ◽  
pp. 957-964
Author(s):  
Wei Zheng ◽  
Hong Zhang ◽  
Xiao Ben Liu ◽  
Le Cai Liang ◽  
Yin Shan Han
Keyword(s):  
Finite Element ◽  
Design Method ◽  
Active Faults ◽  
Shell Element ◽  
High Strength ◽  
Element Model ◽  
Beam Element ◽  
Finite Element Models ◽  
Fixed Boundary ◽  
Equivalent Boundary

There is a potential for major damage to the pipelines crossing faults, therefore the strain-based design method is essential for the design of buried pipelines. Finite element models based on soil springs which are able to accurately predict pipelines’ responses to such faulting are recommended by some international guidelines. In this paper, a comparative analysis was carried out among four widely used models (beam element model; shell element model with fixed boundary; shell element model with beam coupled; shell element model with equivalent boundary) in two aspects: differences of results and the efficiency of calculation. The results show that the maximum and minimum strains of models coincided with each other under allowable strain and the calculation efficiency of beam element model was the highest. Besides, the shell element model with beam coupled or equivalent boundary provided the reasonable results and the calculation efficiency of them were higher than the one with fixed boundary. In addition, shell element model with beam coupled had a broader applicability.

Numerical Research on High-Strength Rectangular Section Steel Tube in Rotary-Draw Bending

2014 ◽  
Vol 620 ◽  
pp. 417-423 ◽  
Author(s):  
Zhong Wen Xing ◽  
Zhi Wei Xu ◽  
Hong Liang Yang ◽  
Cheng Xi Lei
Keyword(s):  
High Strength ◽  
Element Model ◽  
Steel Tube ◽  
Rotary Draw Bending ◽  
Rectangular Section ◽  
Control Variate ◽  
Fillet Radius ◽  
Bending Process ◽  
Bending Radius ◽  
Draw Bending

A finite element model of high-strength rectangular section steel tube in rotary-draw bending is established to study the stress and strain in the bending process. Based on control variate method, this paper analyzes the influence laws of three geometric parameters on rotary-draw bending. The results show that bending radius is the most important factor, forming property increases significantly with the increase of bending radius, the trends of cracking and wrinkling are all decreased. The thickness of wall has influence on the strain of inwall, thinner tube may cause crack and wrinkle. Fillet radius has no effect on ektexine, the strain of inwall decreases slightly with the increase of fillet radius.

Use of DNVGL-RP-C203 for Determining the Fatigue Capacity of Connectors

2021 ◽  
Author(s):  
Anthony Muff ◽  
Anders Wormsen ◽  
Torfinn Hørte ◽  
Arne Fjeldstad ◽  
Per Osen ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Testing ◽  
Experimental Testing ◽  
High Strength ◽  
Element Model ◽  
Fatigue Analysis ◽  
Full Scale ◽  
The Finite Element Model

Abstract Guidance for determining a S-N based fatigue capacity (safe life design) for preloaded connectors is included in Section 5.4 of the 2019 edition of DNVGL-RP-C203 (C203-2019). This section includes guidance on the finite element model representation, finite element based fatigue analysis and determination of the connector design fatigue capacity by use of one of the following methods: Method 1 by FEA based fatigue analysis, Method 2 by FEA based fatigue analysis and experimental testing and Method 3 by full-scale connector fatigue testing. The FEA based fatigue analysis makes use of Appendix D.2 in C203-2019 (“S-N curves for high strength steel applications for subsea”). Practical use of Section 5.4 is illustrated with a case study of a fatigue tested wellhead profile connector segment test. Further developments of Section 5.4 of C203-2019 are proposed. This included acceptance criteria for use of a segment test to validate the FEA based fatigue analysis of a full-scale preloaded connector.

Vibration of Rectangular Plates by the Ritz Method

1950 ◽  
Vol 17 (4) ◽  
pp. 448-453 ◽  
Author(s):  
Dana Young
Keyword(s):  
Ritz Method ◽  
Normal Modes ◽  
Approximate Solutions ◽  
The Other ◽  
Rectangular Plates ◽  
Elastic Plates ◽  
Modes Of Vibration ◽  
Ritz’S Method ◽  
Square Plate ◽  
Set Up

Abstract Ritz’s method is one of several possible procedures for obtaining approximate solutions for the frequencies and modes of vibration of thin elastic plates. The accuracy of the results and the practicability of the computations depend to a great extent upon the set of functions that is chosen to represent the plate deflection. In this investigation, use is made of the functions which define the normal modes of vibration of a uniform beam. Tables of values of these functions have been computed as well as values of different integrals of the functions and their derivatives. With the aid of these data, the necessary equations can be set up and solved with reasonable effort. Solutions are obtained for three specific plate problems, namely, (a) square plate clamped at all four edges, (b) square plate clamped along two adjacent edges and free along the other two edges, and (c) square plate clamped along one edge and free along the other three edges.

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