scholarly journals Composite Single-Bolted Joint Simulation for Dynamic Strength Prediction

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 512
Author(s):  
Zeliang Yu ◽  
Pu Xue ◽  
Yue Chen
Keyword(s):  
Composite Structures ◽  
Dynamic Properties ◽  
Dynamic Strength ◽  
Structural Deformation ◽  
Engineering Practice ◽  
Three Dimension ◽  
Bolted Joint ◽  
Finite Element Software ◽  
Composite Joint ◽  
Significant Difference

Composite material has been widely used in various fields for its high specific strength and high specific stiffness, so the connectors applicable to composite structures capture many researchers’ attention. With the advantages of higher carrying capacity and repetitive assembling and disassembling, bolted joint becomes one of the most popular connectors in engineering practice. Cutting off the fiber and causing stress concentration are more serious to composite than metal, so it is necessary to predict the strength of the composite joints. Most investigations focus on the response under quasi-static loading, while dynamic effects should be in consideration in increasing impact conditions. The dynamic mechanical properties of composite joint may have a significant impact on the structural deformation and damage modes. For this purpose, this paper conducts dynamic composite single-bolted joint simulations in ABAQUS/Explicit, which used for predicting dynamic strength of the composite joint. T800/X850 laminates were tested to investigate their dynamic properties in our lab. Then the three-dimension progression damage model was established, while the dynamic constitutive model, damage initial criteria and damage evolution law of composite materials were coded in VUMAT of the finite element software ABAQUS/Explicit. The model was validated by quasi-static experiments of composite joint. The simulation results indicate that the yield strength and ultimate strength of the single-bolted composite joint are obviously increasing when consider the strain rate effect and dynamic loading. And the load-displacement curves show significant difference in damage stage. The main damages are sub-layer buckling and fiber breakage caused by extrusion.

Strength of Composite Laminated Bolted Joint Subjected to a Clamping Force

2006 ◽  
Vol 326-328 ◽  
pp. 1777-1780
Author(s):  
Jin Ho Choi ◽  
Young Hwan Lee ◽  
Jin Hwe Kweon ◽  
Woo Seong Che
Keyword(s):  
Composite Structures ◽  
Research Area ◽  
Experimental Results ◽  
Clamping Force ◽  
Bolted Joint ◽  
Important Research ◽  
Index Method ◽  
Area Index ◽  
Composite Joint ◽  
Important Research Area

As these composites have become more popular, composite joint design has become a very important research area, as these joints are often the weakest parts of composite structures. In this paper, the strength of a composite laminated bolted joint being subjected to a clamping force was tested and predicted using the FAI (Failure Area Index) method. The strengths of composite joints subjected to clamping forces on different geometric shapes and dimensions were predicted using the FAI method, and the results were compared with experimental results. From the tests and analyses, the strength of a given composite laminated bolted joint subjected to a clamping force could be predicted within 22.5% via the FAI method.

Nonlinear dynamic properties of the rotor-bearing system involving bolted disk-disk joint

2020 ◽  
pp. 095440622097616
Author(s):  
Zhong Luo ◽  
Yuqi Li ◽  
Lei Li ◽  
Zijia Liu
Keyword(s):  
Critical Speed ◽  
Dynamic Properties ◽  
Rotor System ◽  
Structural Parameter ◽  
Largest Lyapunov Exponent ◽  
Three Dimension ◽  
Bolted Joint ◽  
Response Curves ◽  
Typical Structure ◽  
Joint Element

Bolted joints are major components to connect the multiple stages of disks in the aero-engine, which directly influences the motion state of the rotor system. This paper studies the effect of some typical structure parameters on the time-varying bending stiffness of the bolted disk-disk joint through finite-element simulations. Based on the Lagrange’s equations, a two-node element used to represent the bolted joint is derived, which is called the joint element. Then, a mathematical model of the rotor system with a bolted disk-disk joint supported by ball bearings is established through the Timoshenko beam and the joint element. The dynamic model is numerically solved using the Newmark-β method. The largest Lyapunov exponent, three-dimension spectral plots, and frequency-response curves are employed to reveal the effect of the bending behavior on the rotor dynamics. Comparisons indicate that the structural parameter of the bolted joint has a slight influence on motion stability, critical speed, and amplitude corresponding to the critical speed. Finally, an experimental study is conducted through a bolted-disk joint rotor test rig with an electrical tightening wrench, showing that the increase of pre-tightening torque will lead to a decrease of the amplitude corresponding to critical speed due to the hardening effect. The modeling method proposed in the present work paves a way for modeling and analyzing of the rotor system with a bolted disk-disk joint.

scholarly journals Use of Modal Synthesis for Composite Structures

2014 ◽  
Vol 22 (1) ◽  
pp. 69-74
Author(s):  
Miloš Musil ◽  
Ondrej Chlebo
Keyword(s):  
Service Life ◽  
Computational Model ◽  
Composite Structures ◽  
Dynamic Properties ◽  
Engineering Practice ◽  
Common Occurrence ◽  
Modal Properties ◽  
Current Trends ◽  
Modal Synthesis ◽  
Operational Capacity

AbstractA common occurrence in engineering practice is undesirable levels of vibration in the structures of machinery, which decrease their functionality, safety, reliability and service life. Current trends in the dynamic operation of machinery inherently generate such undesirable effects. That is to say, increasing the operational capacity of a machine (higher speeds, higher loads, more changes in operational regimes, etc...) is financially counterproductive to any desired savings in the material/technological realization of such structures. One possible approach to modify the dynamic properties of the structure is through modal synthesis. This approach combines the modal properties of the real structure obtained through measurements with the modal properties of additional components obtained computationally. This approach is particularly effective if the computational model of the built structure is incorrect.

Study on the Dynamic Performance of Asphalt Concrete under Passive Confined Pressure

2012 ◽  
Vol 226-228 ◽  
pp. 1755-1759
Author(s):  
Hua Zhang ◽  
Fei Li ◽  
Yu Wei Gao
Keyword(s):  
Elastic Modulus ◽  
Asphalt Concrete ◽  
Poisson Ratio ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Dynamic Strength ◽  
Confining Pressure ◽  
Mechanical Behaviors ◽  
One Dimensional ◽  
Stress States

An improved passive confining pressure SHPB method was used to study the dynamic mechanical behaviors of asphalt concrete under quasi-one dimensional strain state. The effect of confining jacket material and its geometrical sizes on the confining pressure were discussed. The dynamic strength, dynamic modulus of elasticity and dynamic Poisson ratio of asphalt concrete were obtained. The influential rules of confining pressure on the dynamic properties were studied by comparing the stress-strain curves of asphalt concrete under different stress states. The study found that passive confining greater impact on the strength of asphalt concrete than elastic modulus and Poisson ratio, but the elastic modulus improved with the increase of confining pressure.

Application of Microwave Heating for Adhesive Joining

1999 ◽  
Author(s):  
Erik T. Thostenson ◽  
Tsu-Wei Chou
Keyword(s):  
Microwave Heating ◽  
Composite Structures ◽  
Material Selection ◽  
Adhesive System ◽  
Conventional Heating ◽  
Joint Interface ◽  
Microwave Curing ◽  
Composite Joint ◽  
High Dielectric ◽  
Microwave Techniques

Abstract In conventional joining of composite materials and sandwich structures, reductions in processing time are limited by inefficient heat transfer. In conventional processing the thermal energy must diffuse through the composite layers to heat the joint interface and cure the thermosetting adhesive, and this outside-in process of heating results in excessive processing times and wasted energy. The purpose of the current work is to examine microwave heating as an alternative to conventional heating for joining of composite structures. Through proper material selection, microwaves are able to penetrate the substrate materials and cure the adhesives in-situ. Selective heating with microwaves is achieved by incorporating interlayer materials that have high dielectric loss properties relative to the substrate materials. In this study, a processing window for elevated temperature curing of an epoxy paste adhesive system (HYSOL EA 9359.3) was developed and composite joint systems were manufactured using conventional and microwave techniques and tested in shear. Microwave curing resulted in both enhanced shear strength and less scatter in experimental data.

Dynamic properties of hybrid composite structures based multiwalled carbon nanotubes

2017 ◽  
Vol 148 ◽  
pp. 70-79 ◽  
Author(s):  
H. Benyahia ◽  
M. Tarfaoui ◽  
V. Datsyuk ◽  
A. El Moumen ◽  
S. Trotsenko ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Hybrid Composite ◽  
Composite Structures ◽  
Dynamic Properties ◽  
Multiwalled Carbon

Dynamic Analysis of the Joined-Wing Configuration in High-Altitude Long-Endurance Aircraft Using Fluid-Structure Interaction Model

2007 ◽  
Author(s):  
Prabu Ganesh Ravindren ◽  
Kirti Ghia ◽  
Urmila Ghia
Keyword(s):  
Finite Element ◽  
High Altitude ◽  
Fluid Structure Interaction ◽  
Structural Deformation ◽  
Time Step ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Finite Element Software ◽  
Joined Wing ◽  
Long Endurance

Recent studies of the joined-wing configuration of the High Altitude Long Endurance (HALE) aircraft have been performed by analyzing the aerodynamic and structural behaviors separately. In the present work, a fluid-structure interaction (FSI) analysis is performed, where the fluid pressure on the wing, and the corresponding non-linear structural deformation, are analyzed simultaneously using a finite-element matrix which couples both fluid and structural solution vectors. An unsteady, viscous flow past the high-aspect ratio wing causes it to undergo large deflections, thus changing the domain shape at each time step. The finite element software ANSYS 11.0 is used for the structural analysis and CFX 11.0 is used for the fluid analysis. The structural mesh of the semi-monocoque joined-wing consists of finite elements to model the skin panel, ribs and spars. Appropriate mass and stress distributions are applied across the joined-wing structure [Kaloyanova et al. (2005)], which has been optimized in order to reduce global and local buckling. The fluid region is meshed with very high mesh density at the fluid-structure interface and where flow separation is predicted across the joint of the wing. The FSI module uses a sequentially-coupled finite element equation, where the main coupling matrix utilizes the direction of the normal vector defined for each pair of coincident fluid and structural element faces at the interface [ANSYS 11.0 Documentation]. The k-omega turbulence model captures the fine-scale turbulence effects in the flow. An angle of attack of 12°, at a Mach number of 0.6 [Rangarajan et al. (2003)], is used in the simulation. A 1-way FSI analysis has been performed to verify the proper transfer of loads across the fluid-structure interface. The CFX pressure results on the wing were transferred across the comparatively coarser mesh on the structural surface. A maximum deflection of 16 ft is found at the wing tip with a calculated lift coefficient of 1.35. The results have been compared with the previous study and have proven to be highly accurate. This will be taken as the first step for the 2-way simulation. The effect of a coupled 2-way FSI analysis on the HALE aircraft joined wing configuration will be shown. The structural deformation history will be presented, showing the displacement of the joined-wing, along the wing span over a period of aerodynamic loading. The fluid-structure interface meshing and the convergence at each time step, based on the quantities transferred across the interface will also be discussed.

Manufacturing Error Detection in Plate and Cylindrical Composite Structures

2020 ◽  
Author(s):  
Cihan Talebi ◽  
Bülent Acar ◽  
Gökhan O. Özgen
Keyword(s):  
Error Detection ◽  
Composite Structure ◽  
Composite Structures ◽  
Dynamic Properties ◽  
Dynamic Stiffness ◽  
Element Model ◽  
Mode Shapes ◽  
Fiber System ◽  
Error Identification ◽  
Manufacturing Error

Abstract Due to their superior weight to strength ratio of composites to common metallic structures, composite technology is widely used in aerospace industry. Assessment of damage in composites has gained interest after a large number of accidents caused by unanticipated damages in the composite structures. Many different structural health monitoring applications were developed over the years due to the fact that composite materials may inherit damage from within, not always visible from surface. The most common types of errors encountered in the industry are due to misaligned fibers, a mix-up in ply order, and delaminations: all presenting changes in the vibro-acoustical performance of the composite structure. This paper discusses the change in the dynamic properties of a composite structure contains a manufacturing error such as a ply lay-up error, and a ply angle error. Both plate and cylindrical structure types were considered for the stated error types. Effect of symmetric errors, unsymmetrical and unbalanced errors, and mid-plane errors were considered in the case of ply orientations, and dynamic stiffness matrix was used to identify the error. Identification of the structure’s layup properties and manufacturing error identification is employed. From the measured modal properties of the structure, a back-tracking strategy was used to generate the ply lay-up of the composite structure. Prepreg plates of a single carbon fiber system and filament wound hybrid cylinders consisting of glass and carbon fibers were manufactured for testing. Modal tests on plates and cylindrical composite structures were performed and compared with the analysis. A good match between the finite element model and experiment was shown in natural frequencies and mode shapes.

Neural Networks for the Simulation and Identification Analysis of Buildings Subjected to Paraseismic Excitations

2007 ◽  
pp. 393-432 ◽  
Author(s):  
Krystyna Kuzniar ◽  
Zenon Waszczyszyn
Keyword(s):  
Neural Networks ◽  
Structural Dynamics ◽  
Dynamic Properties ◽  
Response Spectra ◽  
Engineering Practice ◽  
Identification Analysis ◽  
Dynamics Problems ◽  
Mining Tremors ◽  
Testing Patterns ◽  
Mining Regions

The chapter deals with an application of neural networks to the analysis of vibrations of medium-height prefabricated buildings with load-bearing walls subjected to paraseismic excitations. Neural network technique was used for identification of dynamic properties of actual buildings, simulation of building responses to paraseismic excitations as well as for the analysis of response spectra. Mining tremors in strip mines and in the most seismically active mining regions in Poland with underground exploitation were the sources of these vibrations. On the basis of the experimental data obtained from the measurements of kinematic excitations and dynamic building responses of actual structures the training and testing patterns were formulated. It was stated that the application of neural networks enables us to predict the results with accuracy quite satisfactory for engineering practice. The results presented in this chapter lead to a conclusion that the neural technique gives new prospects of efficient analysis of structural dynamics problems related to paraseismic excitations.

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