scholarly journals The Resistance of Welded Joints of Galvanized RHS Trusses with Different Vent Hole Geometries

2019 ◽  
Vol 9 (8) ◽  
pp. 1553 ◽  
Author(s):  
Miguel A. Serrano ◽  
Carlos López-Colina ◽  
Fernando L. Gayarre ◽  
Tim Wilkinson ◽  
Jesús Suárez
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Cross Section ◽  
Welded Joints ◽  
Element Model ◽  
Design Codes ◽  
Zinc Bath ◽  
Joint Resistance ◽  
Valid Solution ◽  
Hollow Structural Sections

A worldwide-accepted technique to protect steel lattice girders with welded hollow sections against corrosion is the hot-dip galvanizing process. In this process, vent holes are required in braces to fill the inner part protecting them from corrosion, to allow the immersion of the structure in the zinc bath and to recover the excess fluid after the bath. The cross-section reduction due to the vent hole could lead to a decrease in the effective brace resistance; this is not easily quantified, because there are neither prescriptions nor recommendations in the design codes to assess this effect. Therefore, the hollow structural sections could be underutilized due to doubts regarding the safety of this type of joint. This research was conducted in order to categorize different geometries and positions of vent holes in order to determine the best in terms of joint efficiency. A validated finite element model considering welds on lattice girders joints was extended to take into account different vent hole shapes. This research concludes that the presence of ventilation holes such as the ones considered in this study does not significantly affect the joint resistance, and that all the analyzed hole shapes could be proposed as a valid solution for machining vent holes. The conclusions drawn up from this work could be useful for structural steel designers, providing them with valuable design recommendations.

Support-Condition Analyses of Rotating Beams Under Distributed Imbalance Loading

2011 ◽  
Author(s):  
Kai Jokinen ◽  
Erno Keskinen ◽  
Marko Jorkama ◽  
Wolfgang Seemann
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Cross Section ◽  
Cross Sections ◽  
Natural Frequencies ◽  
Element Model ◽  
Mode Shapes ◽  
Constant Cross Section ◽  
Support Condition ◽  
Beam Elements

In roll balancing the behaviour of the roll can be studied either experimentally with trial weights or, if the roll dimensions are known, analytically by forming a model of the roll to solve response to imbalance. Essential focus in roll balancing is to find the correct amount and placing for the balancing mass or masses. If this selection is done analytically the roll model used in calculations has significant effect to the balancing result. In this paper three different analytic methods are compared. In first method the mode shapes of the roll are defined piece wisely. The roll is divided in to five parts having different cross sections, two shafts, two roll ends and a shell tube of the roll. Two boundary conditions are found for both supports of the roll and four combining equations are written to the interfaces of different roll parts. Totally 20 equations are established to solve the natural frequencies and to form the mode shapes of the non-uniform roll. In second model the flexibility of shafts and the stiffness of the roll ends are added to the support stiffness as serial springs and the roll is modelled as a one flexibly supported beam having constant cross section. Finally the responses to imbalance of previous models are compared to finite element model using beam elements. Benefits and limitations of each three model are then discussed.

Shock-Resistance Research of Ship Structural Subjected to Underwater Explosion

2014 ◽  
Vol 945-949 ◽  
pp. 1180-1184
Author(s):  
Yao Guo Xie
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Cross Section ◽  
Critical Radius ◽  
Underwater Explosion ◽  
Element Model ◽  
Current Standard ◽  
Envelope Analysis ◽  
Shock Resistance ◽  
Selection Of

A finite element model ships, for example design test condition of the underwater explosion, selection of explosive package quantity is 1000KG TNT, the explosive location along the direction of the ship with the bow, midship and stern, the angle of attack in three exploded cross section have 90 degrees, 60 degrees, 45 degrees, 30 degrees and 0 degrees. According to the current standard to calculate the ship damage radius, critical radius and safety radius of specific values under the effect of underwater explosion, interpolation calculation and draw the envelope. Analysis shows that the vitality of ships and shock-resistance is not only related to the explosive distance, also related to the attack position.

Multi-Objective Structural Optimization of Vehicle Wheels

2021 ◽  
Author(s):  
P. Stabile ◽  
F. Ballo ◽  
M. Gobbi ◽  
G. Previati
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Cross Section ◽  
Element Model ◽  
Computational Effort ◽  
Optimized Design ◽  
Support Design ◽  
Design Constraints ◽  
Multi Objective ◽  
Simplified Finite Element Model

Abstract This work focuses on the development of an innovative design methodology for lightweight wheels of road vehicles. In particular, the activity is carried out for the specific case of a wheel designed for an ultra-efficient vehicle for Shell Eco-marathon competition, with the aim of finding preliminary design solutions. A simplified finite element model of the tire structure is employed for an accurate modelling of the forces acting at the tire/rim interface. The material properties of the tire structure are identified by means of experimental tests. The computed tire/rim force distribution is applied to the rim exploiting a simplified finite element model of the wheel rim. A multi-objective optimization problem is formulated, based on mass and compliance minimization. Several wheel design layouts are investigated, which differ in terms of number of spokes (i.e. 3, 5 and 7), spokes layout (i.e. straight and Y-shape) and spokes cross section (i.e. rectangular, C and I). Geometric quantities related to the cross section dimensions of the spokes and to the rim thickness are optimized. Design constraints related to structural stiffness and elastic stability (both global and local buckling) are taken into account. The developed finite-element based model of the wheel is used to train a set of neural networks to approximate the objective functions and the design constraints to reduce the computational effort. A multi-objective genetic algorithm is adopted to obtain the Pareto-optimal solutions. The implemented method has proved to be a valuable tool to support design engineers in taking critical decisions in the early stages of the design process.

Numerical and experimental study on rotary draw bending of aluminium alloy tubes

2011 ◽  
Vol 2 (1) ◽  
pp. 33-38 ◽  
Author(s):  
L. Lăzărescu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Aluminium Alloy ◽  
Cross Section ◽  
Angular Position ◽  
Element Model ◽  
Quality Parameters ◽  
Wall Thinning ◽  
Bending Process ◽  
Bending Radius

Abstract In this paper a 3D finite element model of the bending process for circular aluminium alloy tube has been built using the explicit code eta/Dynaform and validated by comparing the experiments. The experiments were carried out by using a hand bender with the same bending principle as a rotary draw numerical controlled (NC) bender. The relationship between quality parameters of bent tubes, in terms of cross-section distortion and wall thinning, and the angular position along the bent tube is discussed experimentally in combination with FE simulation. Then, the effects of bending radius (R) are investigated using simulation of the bending process based on the finite element model. The results show that with the increase of bending radius, the cross-section degradation factor (Ψ) and wall thinning degree (ξ) decreases rapidly.

A Concise Finite Element Model for the Analysis of Simple Wire Strand with a Broken Helical Wire

2012 ◽  
Vol 446-449 ◽  
pp. 745-750 ◽  
Author(s):  
Wen Guang Jiang ◽  
Li Juan Yan
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Finite Element Model ◽  
Cross Section ◽  
Axial Load ◽  
Three Dimensional ◽  
Element Model ◽  
Analysis Model ◽  
Symmetric Boundary Condition ◽  
Wire Strand

A concise finite element model for the analysis of simple wire strand with a broken helical wire under axial load is presented in this paper. Due to the implementation of accurate helically symmetric boundary condition, the analysis model can be established based only on a small slice of the wire strand cross-section consisting of all of the remaining intact wires excluding the broken helical wire. Full three-dimensional solid elements were used for structural discretization. The finite element results showed that the sharing of loads among the remaining helical wires is highly non-uniform. The two helical wires adjacent to the broken helical wire bear higher loads. The helical wire opposite to the broken wire bears least load.

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