catia analysis of a piston

7/28/2019 catia analysis of a piston

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UNIVERSITATEA DN PITESTI

TEMA CATIA IICALCULUL TERMIC AL PISTONULUI

Master 2012


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A. Scopul aplicatiei

In cadrul acestei aplica ii se urmre te determinarea deforma iilor si tensiunilor din structura

pistonului determinate de varia iile de temperaturi din timpul func ionarii. Forma si dimensiunile

pistonului sunt prezentate in figura de mai jos.

Pistonul este confec ionat din aluminiu ATC Si10Cu3Mg. Pistonul are forma ovala pe toata

forma sa.

B. ntocmirea modelului de analiza

Pentru ntocmirea modelului de analiza cu elemente finite asociat aplica iei de mai sus se

impune identificarea:

- formei si dimensiunilor geometrice,

- restric iilor induse de legturile cu elementele adiacente,

- restric iilor de isostaticitate,

- incarcarilor exterioare de tip temperatura,


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- caracteristicilor materialului

Distribu iile temperaturii pe suprafa a exterioara a pistonului, in vederea introducerii incarcari,

pentru simplificare, se aproximeaz cu un palier constant corespunztor temperaturii T = 923 grade

Kelvin(650 grade Celsius).

Pentru analiza cu elemente finite caracteristicile fizice ale materialului, ATC Si10Cu3Mg sunt:

modulul lui Young: 7e+010N_m2

coeficientul lui Poisson: 0.346

densitatea: 2710kg_m3

coeficient de dilatare termica (l): 2710kg_m3

coeficient de elasticitate: 9.5e+007N_m2

Dup modelarea pistonului in Start->Mechanical design->Part design se face apel la modulul

de analiza cu elemente finite din catia prin:

Start -> Analysis & Simulation -> Generative Structural Analysis -> New Analysis Case:

Static Analysis ->OK.

Definirea elementelor finite se face din OCTREE Thetraedron Mesh, Size 4mm, Absolute Sag

1mm, Element type Parabolic ->OK.


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C. Modelarea constrngerilor geometrice

Incastrearea pistonului se face apeland User Defined Constraint . Se selecteaza cee doua

gauri de ghidare a boltului in piston si se limiteaza translatia (Isostatic Translation 1).

Introducerea temperaturii:

Temperature field . Support: se selecteaza capul pistonului; Temperature: 923Kdeg; Data

Mapping ->OK.


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D. Rezolvarea modelului cu elemente finite

Lansarea modulului de calcul : Compute -> All -> OK -> Computation Resource Estimation ->Computation Status.

E. Procesarea rezultatelor

Vizualizarea strii deformate/Anima ie


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Deformation

Animate

Vizualizarea cmpului de deplasri

Displacement . Translational displacement magnitude.

Vizualizarea cmpului de tensiuni:


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Principal Stress

Von Mises Stress

Se vizualizeaza toate datele calculului folosind ToolsGenerate Report


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Static CaseBoundary Conditions


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Figure 1

STRUCTURE Computation

Number of nodes : 31785

Number of elements : 17866

Number of D.O.F. : 95355

Number of Contact relations : 0

Number of Kinematic relations : 0

Parabolic tetrahedron : 17866

RESTRAINT Computation

Name: Restraints.1

Number of S.P.C : 831

LOAD Computation

Name: Loads.1


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Applied load resultant :

Fx = -1 . 222e-009 N

Fy = -6 . 312e-010 N

Fz = -6 . 388e-009 N

Mx = -3 . 043e-011 Nxm

My = -3 . 712e-011 Nxm

Mz = -1 . 040e-011 Nxm

STIFFNESS Computation

Number of lines : 95355

Number of coefficients : 3533742

Number of blocks : 8

Maximum number of coefficients per bloc : 499992

Total matrix size : 40 . 80 Mb

SINGULARITY Computation

Restraint: Restraints.1

Number of local singularities : 0

Number of singularities in translation : 0

Number of singularities in rotation : 0

Generated constraint type : MPC

CONSTRAINT Computation


Number of constraints : 831


Number of factorized constraints : 831


Number of deferred constraints : 0

NUMBERING Computation


Numbering Method : SLOAN

Number of connected nodes : 31785

Nodal maximum front width : 1370

Nodal maximum band width : 9227

NtKNScaled Computation


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PRECONDITIONER Computation

Conjugate Gradient : in core

Preconditioner : incomplete factorization






GRADIENT Computation

Name: Static Case Solution.1


Load: Loads.1

Number of independent DOF : 94524

Number of Contact Elements : 0

Maximum number of iterations : 0

Number of iterations already performed : 0

Convergence at iteration : 400Precision reached : 1 . 016e-012

Strain Energy : 5.274e+001 J

Equilibrium

ComponentsAppliedForces

Reactions ResidualRelative

Magnitude Error

Fx (N) -1.2224e-009 -2.5297e-006 -2.5309e-006 7.8556e-011

Fy (N) -6.3119e-010 0.0000e+000 -6.3119e-010 1.9591e-014


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Fz (N) -6.3883e-009 0.0000e+000 -6.3883e-009 1.9828e-013

Mx (Nxm) -3.0425e-011 0.0000e+000 -3.0425e-011 2.3757e-014

My (Nxm) -3.7119e-011 -1.4472e-008 -1.4509e-008 1.1329e-011

Mz (Nxm) -1.0402e-011 -5.7938e-010 -5.8979e-010 4.6053e-013

Static Case Solution.1 - Deformed mesh.2

Figure 2

On deformed mesh ---- On boundary ---- Over all the model

Static Case Solution.1 - Von Mises stress (nodal values).2


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Figure 3

3D elements: : Components: : All

On deformed mesh ---- On boundary ---- Over all the model

Global Sensors

Sensor Name Sensor Value

Energy 52.737J

catia analysis of a piston

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