Simulation of Impact of PET venturi tube with rigid floor

 

Date: Tuesday, May 07, 2013
Designer: Ammar Aziz                                                                                                           Study name: Impact testing by Ammar                                                                             Analysis type: Drop Test

Disclaimer: The results of this simulation can not be used for any practical implementation.

Solid Body
Document Name and Reference	Treated As	Volumetric Properties	Document Path/Date Modified
Venturi Impact	Solid Body	Mass:0.190265 kg Volume:0.00013399 m^3 Density:1420 kg/m^3 Weight:1.8646 N	May 07 12:56:49 2013

 

Study Properties

Study name	Venturi Impact
Analysis type	Drop Test
Mesh type	Solid Mesh
Large displacement	On
Result folder	SolidWorks document

 

Setup Information

Type	Drop height
Drop Height from Centroid	2000 mm
Gravity	9.81 m/s^2
Gravity Reference	Top Plane
Friction Coefficient	0
Target Stiffness	Rigid target
Critical Damping Ratio	0

Drop height is selected from the automatically detected geometric center of tube to the floor surface. So please not confuse this length with the distance between the lower portion of tube and floor surface 

Also the friction between the tube and floor is neglected. This assumption is based on another assumption that tube is falling perfectly vertically, so that there is no side thrust which enhances the friction process during the impact.

The floor is assumed to be rigid. It implies all the potential energy of the tube is dissipated into the floor without any rejection of energy by floor back to tube.

 

Result Options

Solution Time After Impact	130.7 microsec
Save Results Starting From	0 microsec
No. of Plots	25
No. of Graph Steps Per Plot	20
Number of vertex	0

The simulated result span is b/w time of impact to 130 lacth second after the impact

Units

Unit system:	SI (MKS)
Length/Displacement	mm
Temperature	Kelvin
Angular velocity	Rad/sec
Pressure/Stress	N/mm^2 (MPa)

Material Properties

Model Reference	Properties	Components
	Name: PET Model type: Linear Elastic Isotropic Default failure criterion: Unknown Tensile strength: 5.73e+007 N/m^2 Compressive strength: 9.29e+007 N/m^2 Elastic modulus: 2.96e+009 N/m^2 Poisson's ratio: 0.37 Mass density: 1420 kg/m^3	SolidBody 1(Shell3)(venturi tube)

The model is assumed to be linear elastic and isotropic. It implies Hook’s law is valid during the entire simulation. Elastic modulus of material is approximately 3GPa.

 

Mesh Information

Mesh type	Solid Mesh
Mesher Used:	Standard mesh
Automatic Transition:	Off
Include Mesh Auto Loops:	Off
Jacobian points	4 Points
Element Size	0.00511862 m
Tolerance	0.000255931 m
Mesh Quality	High

Mesh Information - Details

Total Nodes	13311
Total Elements	15359
Maximum Aspect Ratio	5.3887
% of elements with Aspect Ratio < 3	99.5
% of elements with Aspect Ratio > 10	0
% of distorted elements(Jacobian)	0
Time to complete mesh(hh;mm;ss):	00:00:21

It is a fine mesh with no distorted element. All the elements are less than aspect ratio of 3. Approximately 13 thousand nodes. So a good solution is expected.

Study Results

Name	Type	Min	Max
Stress1	VON: von Mises Stress	1.50947 N/mm^2 (MPa) Node: 1927	35.3117 N/mm^2 (MPa) Node: 7042

As the maximum stress generated due to impact is approximately 35 MPa which is well below the tensile strength of 3GPa. So our model is safe. But the neck is critical is the tube falls from more high heights.

Name	Type	Min	Max
Strain1	ESTRN: Equivalent Strain	0.000561001 Element: 2362	0.00995434 Element: 3707

Conclusion:

you can see the most sensitive location is the neck of venturi tube if it falls from certain height vertically according to above scheme.

Disclaimer:

This simulation is just to describe the capability of solid works to simulate the impact test. Also it encourages the sound theoretical knowledge development.