This is to certify that the thesis prestressed modal analysis of nonuniform beam in ansys, submitted by ayush agarwal and mohammed istiyaq, b. In this contribution, it is intended to investigate the effect of prestress on the vibration behavior of simple structures using finite element package ansys. In commercial fem systems, like abaqus, the modal analysis of prestressed structures. Firstly, a prestressed modal analysis was conducted to measure the influence of the prestressing on. My interest about adding a prestress is to use it to run the prestress modal analysis to have stiffening effect. Using finite element techniques boundary element methodfinite element method.
Wireless operational modal analysis of a multispan prestressed concrete bridge for structural identification583 entire span on the deck surfacing alongside the parapets and directly over the exterior beams. Frictional contact retained the initial status throughout the modal analysis. The paper deals with the finite element modal analysis of a turning tool assembly, using advanced contact technology functionalities. Prestressed modal analysis using finite element package ansys. Modern antenna design using mode analysis techniques. A close look at the design steps of many of the available modern. This paper is based on the research on the drive shaft of the toothpaste tube conveyor, using solidworks to create the three dimensional model of the frame of the soft tube conveyor and the drive shaft. Displacement and frequencies of cantilever beam are studied with distributed as well as point load. The picture shows a sectional view of the horn cut along the symmetry plane. Xansys view topic xansys modal prestressed analysis. I try to find the method to do prestressed modal analysis based on the deformed configuration rather than initial configuration. In every development of a new or improved mechanical product, structural dynamics testing on product prototypes is used to assess its real dynamic behavior.
Modal analysis of a cablestayed bridge liuchuang weia, heming chenga. Modal analysis of prestressed spindle component based on workbench. Pretensioned prestressed concrete bridge beams and bridge. Vibration characteristics analysis of mistuned bladed disk. This method involves a single linear qr damped or unsymmetric eigen solver. Since the measured data can be in the form of either frequency response functions or of impulse responses, there are frequency domain modal analysis and time domain modal analysis. Modal analysis of prestressed draft pad of freight wagons.
A number of bridge failures all over the world due to faulty prestressing systems have drawn the attention of researchers towards assessing the effective prestress force in prestressed bridges. The hybrid tower is composed of prestressed concrete at the bottom and steel at the top. Request pdf prestressed modal analysis using finite element package ansys it is customary to perform modal analysis on mechanical systems without. Prestressed analysis with the xed interface modal solution with the free interface f. The natural frequencies and deformation of the prestressed spindle component assembly are separately analyzed by means of ansys workbench software in this paper. Understanding both the natural frequency and mode shape helps to design my structural system for noise and vibration applications. Bolt is connected to a connecting body which is turn is connected to ultrasonic horn. The performance of these prestressed structures is governed by the effective prestress force which in fact reduces over time. Ansys cantilever beam modal analysis simcafe dashboard. Practical testing shaker bed testusing an impact hammer 2.
Pdf prestressed modal analysis of composite bolted structure. For the prestressed modal analysis, the stress field is taken into account by modifying the stiffness matrix k. A new mobile interface prestressed component mode synthesis cms superelement method is proposed with the mobile interface prestressed and free interface superelement approach. Apr 08, 2012 i tried the prestressed eigenvalue cases. Ce6702 notes syllabus all 5 units notes are uploaded here. Pdf prestressed modal analysis of composite bolted. For this, different research papers were studied and considering the resear ch issues, objectives are. Solid slab is ideal for short spans with shallow construction depths. The fe modelling, analysis and findings are summarised in this paper. Ce6702 prestressed concrete structures syllabus notes. Below is a finite element representation of the rectangular plate. Prestressed modal analysis linked to nonlinear static.
In the first step, a nonlinear static solution with a prestress effect is performed. A new proposal for the prestressed concrete structural for hwtt to tackle and develop this problem. Pzt stacks are gonna be prestressed by a bolt and nut. Xansys kspin for large displacement prestressed modal analysis i recently got what i believe to be incorrect advice from ansys support regarding the use of kspin with a large displacement prestressed modal analysis. Prestressed static analysis to establish contact between the pads and disc forced frictional sliding between pads and disc to generate non symmetric stiffness matrix prestressed modal analysis to generate complex eigen frequencies positive real part of. And natural frequencies and vibration modes of preceding 6 modalities of prestress modal analysis are calculated with ansys workbench.
Displacement and frequencies of cantilever beam are studied with distributed as well as. The schematic setup for modal free vibration is shown here. The 3d steadystate analysis results were then used as initial conditions for the subsequent prestressed modal analysis. Mar 24, 2011 for example, if the prestress analysis was run using frictional contact, the subsequent modal analysis can be run utilizing the prestressed state of the structure but with one of three contact states for the modal analysis. Uniform spacing was employed across each span with five sensors allocated per side of the individual spans.
The procedure for performing a modal analysis of the prestressed concrete slab in finite element program ansys is concerned by the effect of initial stress on the dynamic response of the concrete structure and includes structural and modal analysis. Solid slab deck infill deck, beam and slab deck, voided bridge deck. The focus was prestressed modal analysis of bolted joint to predict and reduce loosening. The steel tower parts must be strong and rigid, leads to high construction costs, long service life, and fewer maintenance needs. Specifically, we will load the link with a 4000 n tensile load and compare the natural frequency to that of the unloaded component. But i think in these cases, the deformation of structure is not taken into account in the following eigenvalue analysis. Analysis process of prestressed cms superelement method is shown in figure.
International conference on multidisciplinary research. Vibration characteristics of blisk structure accuracy verication of the prestressed cms method. Notably, modal analysis of antennas has long been known in the antenna community. Modal analysis is a process of extracting modal parameters natural frequencies, damping loss factors and modal constants from measured vibration data. Modal analysis superelement 1 superelement 2 transfer back to physical coordinate of substructure 1 transfer back to physical coordinate of substructure 2 use pass step 2 pass step 1 expansion pass step 3 transfer back to physical. Research article vibration analysis of aeroengine blisk. For this example, use lanczos method to find the first five natural frequencies and mode shapes of a flat rectangular plate.
Then, a prestressed modal analysis is performed to obtain all mode shapes in the frequency range of interest. So, basically, modal analysis is the study of the natural characteristics of structures. A static structural analysis was performed and the stifness contribution was included in the modal prestressed analysis. The overall objective is to detect, localize, identify and quantify the. Ce6702 pcs syllabus notes download link is provided and students can download the ce6702 syllabus and lecture notes and can make use of it. For example, if the prestress analysis was run using frictional contact, the subsequent modal analysis can be run utilizing the prestressed state of the structure but with one of three contact states for the modal analysis. The free vibration analysis procedure is very similar to performing a linear static analysis, so not all steps will be covered in detail. Prestressed static analysis to establish contact between the pads and disc forced frictional sliding between pads and disc to generate non symmetric stiffness matrix prestressed modal analysis to generate complex eigen frequencies positive real part of the eigen frequencies indicates unstable mode analysis steps.
Workshop 1 modal analysis of a flat plate mscnastran102 exercise workbook model description. The proposed tower is designed as an eightpart section with internal stiffeners at the bottom along the top of the tower, which. The girder is designed as fishbellied prestressed concrete box girder, considering that fishbellied prestressed concrete box beam have a good visual effects and it is beneficial to wind resistance. Analysis accuracy of this method is verified by the cyclic symmetry analysis method and the direct method. Damage identification based on modal analysis of prestressed. We use modal analysis to help design all types of structures including automotive struc. The result thus obtained was verified with the result as obtained as the output of the programme in other literature survey. Modal analysis or natural frequency analysis is usually carried out for complex structures by 2 means 1. Jul 21, 2009 i wanna do a prestressed modal analysis on mems structure.
Nonlinearities can result from any combination of large displacement, nonlinear contact, or material nonlinearity in the analysis. The structure of the cablestayed bridge is complex, and the cables are flexible, lightweight, low damping, etc. Consider an aluminum beam that is clamped at one end, with the following dimensions. Prestressing for reduction of local vibrations in a. Scribd is the worlds largest social reading and publishing site. While evaluating the mode shapes, the material is assumed to behave linearly elastic neglecting nonlinearities, damping is not included, and no excitation of the structure is assumed. Abstract this thesis presents two novel nonlinear modal analysis methods, aimed at the identification of representative engineering structures. Analytical modal analysis depends on the generation of the equations of motion of a system through a finite element model. Prestressed modal analysis of the shaft based on ansys. Analytical modal analysis modal analysis is the process of characterizing the dynamic response of a system in terms of its modes of vibration. For a free vibration analysis, the natural frequencies. The mistuning parameter of real blades is identified by modal testing and finite element method, and the. Consequently the modal analysis of the cablestayed bridge is essential to study the dynamic behavior of cablestayed bridge.
Modal analysis of prestressed spindle component based on. Linear nonprestressed modal analysis a linear nonprestressed modal analysis is effective when large deflection or stress stiffening effects are not critical and prestress effect is not included. By analyzing the natural frequencies of the drive shaft. Prestressed modal analysis using finite element package. Today, modal analysis has become a widespread means of finding the modes of vibration of a machine or structure figure 3. However, there is little information available in literature about prestressed modal analysis of gearbox casing.
Nov 28, 2015 prestressed modal analysis of non uniform b. Modal analysis of prestressed concrete wind turbine tower. Apr 18, 2005 the modal section but the problem is the following. We recommend that you register using the same email address you use to maintain your asce member account. Modal analysis theory 2 the vibration characteristics decide the dynamic response characteristics. While evaluating the mode shapes, the material is assumed to behave. Ce6702 pcs syllabus notes download link is provided and students can download the ce6702 syllabus and lecture notes and can make use. The steadystate analysis of the 3d model was performed in order to correlate the 3d stress results with the 2d stress results acting on the spacer. The results show that the structural parameters have large influence on spindle inherent frequency, it is important to optimize the design structure to make the inherent frequency of the spindle away from work frequency. This approach is of course well accepted in general.
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