scholarly journals NUMERICAL SIMULATION OF RIVETING PROCESS USING BLIND RIVET

Aviation ◽  
2006 ◽  
Vol 10 (2) ◽  
pp. 7-12
Author(s):  
Lucjan Witek
Keyword(s):  
Stress Distribution ◽  
Strain Distribution ◽  
Initial Stresses ◽  
Aviation Industry ◽  
The Finite Element Method ◽  
The Core ◽  
Riveting Process ◽  
Nonlinear Computation ◽  
Core Displacement ◽  
Mechanical Phenomena

This paper is concerned with an analysis of the mechanical phenomena occurring in the process of blind riveting. Blind rivets are commonly used in the aviation industry and allow riveting with one‐sided access. To solve this problem, the finite element method was used. In results of the nonlinear computation performed for a joint containing one rivet, the stress distribution in the separate phases of riveting were analyzed. The plots of riveting force in function of rivet core displacement for different friction coefficients between the rivet and the core and the plastic strain distribution also were obtained. The main purpose of this work was to obtain the initial stress distribution occurring in the rivet and sheets after the mandrel was broken. This analysis showed that after finishing the riveting process the initial stresses occurring in the rivet have high values.

scholarly journals Numerical and Experimental Study on TC4-DT Titanium Alloy Structure after Double Cold Expansion

2018 ◽  
Vol 36 (4) ◽  
pp. 701-708
Author(s):  
Lubin Huo ◽  
Zengqiang Cao ◽  
Fan Zhang ◽  
Yuejie Cao
Keyword(s):  
Stress Distribution ◽  
Strain Distribution ◽  
Residual Stress Distribution ◽  
Aviation Industry ◽  
Alloy Structure ◽  
Distance Ratio ◽  
Interference Fit ◽  
Cold Expansion ◽  
Modelling Method ◽  
Good Agreement

Cold Expansion and Interference Fit are two well-known techniques in hole strengthening, having been widely used in aviation industry. Double cold expansion is a new strengthening process which effectively combined with the two techniques. A modelling method based on ABAQUS finite element method is proposed in order to study the effect of double cold expansion, which will include cold expansion, reaming process, interference fit and springback after that, the influence of edge distance ratio (EDR) on the stress-strain distribution has been studied. Proto-LXRD device has been used to measure the residual stress distribution in the surface of the specimens. Simulation and experimental results show that the stress distribution of the simulation is in an higher level than that of experimental, but the trends of the stress distribution are in a good agreement.

Improving Fatigue Life of Riveted Joints by Rivet Hole Sizing

2014 ◽  
Vol 598 ◽  
pp. 141-146
Author(s):  
Adam Lipski ◽  
Zbigniew Lis
Keyword(s):  
Fatigue Life ◽  
Fold Increase ◽  
Fatigue Tests ◽  
Aviation Industry ◽  
Lap Joint ◽  
Riveted Joints ◽  
Riveting Process ◽  
The Difference ◽  
Structural Connection ◽  
The Impact

The aim of this paper is to assess the impact of the rivet hole sizing process on the fatigue life based on the example of the structural connections characteristic for riveted joints used in aviation industry. Test specimens reflected the structural connection consisting in a riveted lap joint of an airplane plating stiffened with a T-bar. Connected plates and the T-bar are made of D16CzATW aluminum alloy. 3 mm diameter oval head solid rivets for aviation-related purposes were made of PA24 aluminum. During fatigue tests, individual specimens with non-sized holes and with sized holes were subjected to uniaxial, one-sided, fixed-amplitude loading (R = 0). It can be concluded from the fatigue life comparison that introduction of an additional operation in the riveting process, i.e. the hole sizing, results in significant, about two-fold increase of the fatigue life of the riveted structural connection, even at slight sizing degree. The difference of the specimen damage nature was observed between specimens with sized and non-sized holes.

The Effect of Thermal Prestress on the Deformation of Micromirror Chip Embedded with Through-Silicon Vias

2011 ◽  
Vol 462-463 ◽  
pp. 563-568 ◽  
Author(s):  
Meng Kao Yeh ◽  
Chun Lin Lu
Keyword(s):  
Stress Distribution ◽  
Room Temperature ◽  
Thermal Loading ◽  
Heat Transfer Analysis ◽  
Processing Temperature ◽  
Temperature Decrease ◽  
Analysis Method ◽  
The Finite Element Method ◽  
Through Silicon Vias ◽  
Silicon Vias

The thermal expansion mismatch problem for a chip due to temperature decrease from processing temperature to room temperature may cause residual stress inside the chip structure. The thermal prestress accumulated and may affect the chip reliability when the chip was subjected to the thermal loading again. In this paper, the effect of thermal prestress on the micromirror chip embedded with copper through-silicon vias (TSVs) was investigated by the finite element method. In analysis, the micromirror chip embedded with TSVs was analyzed first under thermal loading which resulted from temperature decrease between the stress free processing temperature and room temperature. This process produced a thermal prestress in the micromirror chip. The chip was then subjected to a heat source at the bottom while in operation and the heat transfer analysis was used to simulate this situation. Finally, the thermal stress analysis was carried out to obtain the deformation and the stress distribution in the chip. The results show that the thermal prestress had strong effect on the chip reliability and should be reduced as much as possible. This paper proposed a three steps analysis method to obtain the deformation and the stress distribution in the chip, in which the effect of thermal prestress on the chip reliability was evaluated effectively.

Strain Analysis of Composite Frame Joints with Double Side Penetrated Diaphragms

2012 ◽  
Vol 166-169 ◽  
pp. 3277-3281
Author(s):  
Min Tong
Keyword(s):  
Stress Distribution ◽  
Strain Analysis ◽  
Steel Tube ◽  
Core Region ◽  
Steel Beam ◽  
Static Test ◽  
The Core ◽  
Composite Frame ◽  
Joint Connection ◽  
New Type

Abstract. Connection joint with penetrated diaphragm, which is better for the stressing state of the welding connection, is a new type joint for the beam and column connection. Static test and pseudo-static test are put to 17 crossing joints. The stress distribution of the steel beam and the penetrated diaphragm are discussed. The experiment shows that the penetrated diaphragm transfer most tension force of the steel beam’s upper flange to the core region of the joint, which could effectively decrease the stress and strain gradient within the connection area of the steel beam’s upper flange and steel tube column. As the result, the shear force of the core region is decreased. The front weld is avoided being surfing great tension. The ductility of the joint and the energy dissipation capacity of the structure are then increased. The type and the size of the penetrated diaphragm show great affection to the stress distribution of steel beam and penetrated diaphragm. The study achievement enriches the joint connection type of the composite structure with concrete- filled steel tube.

scholarly journals ASSESSMENT OF THE STRENGTH OF A COMPOSITE PACKAGE WITH INTERNAL DEFECTS ACCORDING TO VARIOUS FAILURES CRITERIA UNDER THE INFLUENCE OF UNSTEADY LOAD

2020 ◽  
Vol 17 (35) ◽  
pp. 1218-1230
Author(s):  
Aleksandr L. MEDVEDSKIY ◽  
Mikhail I. MARTIROSOV ◽  
Anton V. KHOMCHENKO ◽  
Darina V. DEDOVA
Keyword(s):  
Polymer Composite ◽  
Longitudinal Direction ◽  
Polymer Composite Material ◽  
Aviation Industry ◽  
Structural Elements ◽  
The Finite Element Method ◽  
Fracture Criteria ◽  
Safety Factors ◽  
Elliptical Shape ◽  
And Behavior

One of the priority tasks of the modern aviation industry is to increase the economic efficiency of aircrafts. In the context of solving this problem, when creating new aircrafts, polymer composite materials (PCM) are increasingly used. Particular attention is paid to structural elements, damage to which can lead to a decrease in the strength of an airframe as a whole. Therefore, an essential task in the design, maintenance, and operation of the test is to study the effect of interlayer defects on the strength and behavior of PCM structures under the influence of unsteady loads. This work is devoted to a numerical analysis of the behavior of a plate made of a polymer composite material (PCM) under unsteady load considering interlayer defects of an elliptical shape, as well as an assessment of the strength of a composite package according to various fracture criteria. The problem is solved by the finite element method using the LS-DYNA software package. Then, using the method of mathematical modeling, the interlayer separation of an elliptical shape was analyzed, which allowed to evaluate the strength of the plate and fiber according to the criteria of Hashin, Puck, Chang-Chang, and LaRC03 and compare the results. It was found in the study, that the failure indices and safety factors, which were obtained using various criteria (Hashin and Chang-Chang), have the same distribution, since the dependence of the implemented fracture mode (fiber compression in the longitudinal direction) is identical. Analysis.

Study on the Steady State Thermal Circuit Model of 10kV Three-Core Cable Based on the Shape Factor Method

2014 ◽  
Vol 1008-1009 ◽  
pp. 593-597
Author(s):  
Wen Xiang Li ◽  
Rui Bo Su ◽  
Gang Liu ◽  
Peng Wang ◽  
Yi Xuan Chen
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Shape Factor ◽  
Field Research ◽  
Circuit Model ◽  
The Finite Element Method ◽  
Heat Transfer Characteristics ◽  
Thermal Circuit ◽  
The Core ◽  
Conductor Temperature

The core of the 10kV three-core cable is in the shape of a trefoil. Not all the radial direction of the actual heat transfer characteristics are the same. The finite element method serve as the three core cable temperature field research method in this text, in order to analyze the internal temperature distribution of three core cable, establish a steady state thermal circuit model in accordance with the characteristics of heat transfer from the cable conductor to the surface in the three-core cable , give the calculation of conductor temperature algorithm, and calculate the various parameters in the model.

FEM Simulation of the Effects of Residual Stress on Deformation of Gyroscope Frame

2010 ◽  
Vol 439-440 ◽  
pp. 838-841
Author(s):  
Jun Zhan ◽  
Gui Min Chen ◽  
Xiao Fang Liu ◽  
Qing Jie Liu ◽  
Qian Zhang
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Tensile Stress ◽  
Large Deformation ◽  
Deformation Process ◽  
Fem Simulation ◽  
Machining Process ◽  
The Core

Gyroscope is the core of an inertia system and made by machining process. Machining process imports large residual stress. The residual stress will be released and induces large deformation of gyroscope frame. In this paper, the effects of residual stress on deformation of gyroscope frame were simulated by finite element method. Different stress distribution leads different deformation. Compressive stress can make sample long and tensile stress make sample short. The stress released in deformation process which reduced about 90%.

Vibro-Acoustic Analysis and Topology Optimization of Anti-Tetra Chiral Auxetic Lattices Driven by Different Colored Noises

2020 ◽  
Vol 20 (11) ◽  
pp. 2050113
Author(s):  
A. Hosseinkhani ◽  
D. Younesian ◽  
M. Ranjbar
Keyword(s):  
Boundary Conditions ◽  
Natural Frequencies ◽  
Acoustic Analysis ◽  
Honeycomb Structure ◽  
Geometrical Parameters ◽  
Acoustic Behavior ◽  
The Finite Element Method ◽  
Load Spectrum ◽  
The Core ◽  
Radiated Sound

In this paper, we study vibro-acoustic behavior of auxetic sandwich panels subjected to different excitations and boundary conditions. The core of this panel has the auxetic feature (with negative Poisson’s ratio or NPR) with anti-tetrachiral honeycomb structure. Mechanical behavior of the core is formulated using theoretical relations presented for this kind of auxetic. Using the Finite Element Method, the modal analysis and spectral analysis of the structure are accomplished. Different random colored noises are applied as the system excitation. First, a parametric study is performed; and some interesting results are observed from investigating the effects of geometric parameters, boundary conditions, and noise color on the vibro-acoustic behavior of the structure. These parameters affect the natural frequencies, level of radiated sound, and mass of the structure. An optimization algorithm is applied to the geometrical parameters in order to simultaneously reduce the level of radiated sound and preserve the amount of total mass. By the use of the Genetic Algorithm (GA), we could achieve a remarkable noise attenuation gain. It is shown that the GA choses different optimized parameters for the structure according to the location of the load and frequency content of the load spectrum.

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