final by ashar - Copy.pptx

1. Development of constitutive model of a
solid composite propellant and
investigate its mechanical properties
Thesis Supervisor
Asst. Prof. Dr. Raees Fida Swati
By
Yasir Bhutto
Syed Ashar
INSTITUTE OF SPACE TECHNOLOGY, ISLAMABAD 1

2. CONTENTS
2

3. INTRODUCTION
What is constitutive modeling ?
Figure 1 Actual and Predicted SS curve
• The art of describing the mechanical properties of
materials through mathematical models is called
constitutive modeling.
• Constitutive models describe the material responses
to different mechanical and thermal loading
conditions, it helps to predict behavior of material.
• In this project we are also investigating mechanical
properties of monomodal, bimodal, trimodal
composite solid propellants.
Figure 2 Procedure How Constitutive modeling works
3

4. INTRODUCTION
What is composite solid propellant?
• In a heterogeneous or solid composite propellant, the ingredients
are physically mixed, leading to a heterogeneous physical structure.
• It is composed of crystalline particles acting as oxidizer and organic
plastic fuels acting as binder to adhere oxidizer particles together.
• In a heterogeneous or composite propellant, the ingredients are
physically mixed, leading to a heterogeneous physical structure. It
is composed of crystalline particles acting as oxidizer and organic
plastic fuels acting as binder to adhere oxidizer particles together.
• A heterogeneous mixture is a mixture where throughout the
solution the composition is not uniform. By definition, a single-
phase consists of a pure substance or a homogeneous mixture. There
are two or more phases of a heterogeneous mixture.
Figure 3 Homo and Hetro mixture
4

5. INTRODUCTION
Where composite solid propellants are used?
• They are mainly used in Solid Rocket Motors.
Figure 3 Use of propellants in solid rocket motors 5

6. Composite Main Grain Configurations
Three
Gain Size
Dual Grain
Size
Single
Grain
Size
Trimodal
Bimodal
Monomodal
.
Figure 4 Mono Bi Tri grain configurations 6

7. Selection of Material
HTPB - AI - AP
• HTPB (Hydroxyl-terminated polybutadiene) is polymer liquid
(Binder)
• HTPB is a fuel rich composite
• An important application of HTPB is in solid rocket
propellant (widely used). It binds the oxidizing agent, fuel
and other ingredients into a solid but elastic mass in most
composite propellant systems. The cured polyurethane acts
as a fuel in such mixtures.
• Aluminum powder (Fuel)
• AP Aluminium Perchlorate is a powerful oxidizer
7

8. Selection of Material
Composition of Composite Solid Propellant
Binder = HTPB (Hydroxyl-terminated polybutadiene)
Oxidizer = AP (Aluminium Perchlorate)
Fuel = AI (Aluminium)
Figure 4
Material Grain Size µm
(mono)
Grain Size µm
(bi)
Grain Size µm
(tri)
By Weight %
AP 300 300,50 300,50,6 67
AI 15 15 15 16
HTPB - - - 17
Table 1 Grain size configurations of HTPB AI AP 8

9. LITERATURE SURVEY
Mechanical properties and constitutive model of a composite solid
propellant under the synergistic effects of accelerated aging time, pre-strain,
and damage growth.
Mechanics of Materials 148 (2020)
By Jianjun Wanga, Jiming Chenga, Ming Leia, Xueyao Hub, Lihua Wena
Materials tested
HTPB – AI - AP
• Binder HTPB - 17% : hydroxyl- terminated polybutadiene Oxidizer AP - 67% - amonium perchlorate
Fuel Al - aluminium - 16%
Problem Statement
• To evaluate Mechanical properties and constitutive model of a composite solid
propellant under the synergistic effects
9

10. LITERATURE SURVEY
(1) The stress−strain behavior of the HTPB/AP-based propellant was
greatly dependent on the accelerated aging time and pre-strain.
With the increasing pre-strain, the value of ER first increased and
then decreased.
(2) When the pre-strain reached 12%, a large number of pores appeared
in the microstructure of the propellant after accelerated
aging.
(3) The variation of the damage variable D occurred.
(4) A constitutive model, considering the synergistic effects of viscoelasticity,
accelerated aging time, pre-strain during aging, and damage
growth, was proposed to accurately predict the stress−strain
response of the propellant after different accelerated aging times
with different pre-strains.
Findings From Research Paper
10

11. LITERATURE SURVEY
With the purpose of investigating the effects of confining pressure and aging on the mechanical
properties of Hydroxyl-terminated polybutadiene (HTPB) based composite solid
propellant, tensile tests of thermal accelerated aged propellant samples under room temperature
and different confining pressure conditions were performed through the use of a self-made
confining pressure device and conventional testing machine.
Problem Statement wtd add title
11

12. LITERATURE SURVEY
Findings From Research Paper
 The results indicate that confining pressure and aging can significantly affect the mechanical
properties of HTPB propellant, and the coupled effects are very complex.
 the stress σm increases as a whole when confining pressure becomes higher or thermal aging
time rises
 maximum value of the stress increment for the propellant is about 98% at 7.0 MPa the
strain εm decreases with increasing thermal aging time under the whole confining pressure
conditions
 Therefore, the proposed strength can be selected as a failure criterion for the analysis the
failure properties of aged HTPB propellant under different confining pressures.
12

13. EXPERIMENTAL DATA FROM LITERATURE SURVEY
Figure 5 Experimental Procedure for constitutive modeling 13

14. NUMERICAL ANALYSIS
Figure 6 Modeling of speciman
14

15. DELIVERABLES OF PROJECT
To develop a constitutive model and investigate its mechanical properties.
• Constitutive Modeling of Composite Solid Propellant.
• Study Damage Growth Model.
• Investigation of properties by Accelerated Aging.
• Investigation of Mechanical Properties.
15

16. METHODOLOGY
Literature
Literature Review
Selection of
Material
Research on
existing models
Study constitute
model
Study mechanical of
properties
HTPB AI AP
Mono Bi Tri
Specimen dimension
Grain Size
Densities
Composition
Numerical
Analysis
Analytical Analysis
Specimen
Tensile Test
Study
Damage Growth
Modelling
Validation with Experimental
Data
FEM
Boundary Conditions
By Young's Modulus
Accelerated Aging
Creep Test
Pre- Strain
Relax Model
16

17. METHODOLOGY
Numerical Analysis
Compare the Properties
Mechanical
Properties
Tensile Test with Pre
stresses
Compare Properties
Tensile Test
Accelerated Aging +
Tensile Test
Investigate them
Constitutive Model
Damage Growth
Accelerated Aging
Computational
Analysis
Aerospace
Application
Modelling in ANSYS
Composite
FEM ( mesh generation)
Static Structural and Explicit
Dynamics Analysis
Simulations
Modelling in ANSYS Composite –
based on experimental data
Validation with Experimental
Data
FEM
Static and Dynamic Analysis
Simulations
Used to predict properties of
solid composite propellants
Helps to modify structural
characteristics of solid rocket
motors where propellant are
used
Helps to select the best
appropriate propellant and
design
Conclusions
Evaluate results
17

18. COMPUTATIONAL ANALYSIS
120 mm
25 mm
Figure 1 Dimensions of Specimen
Modelling and Meshing
Static Structural and Explicit Analysis
Specimen Modelling
18

19. TENSILE TEST
Tensile Test is performed under different pre strain i.e Displacement in order to identify
mechanical properties and to Analyze Damage in a material.
Tensile test is performed in following way:
• ANSYS Software is use
• Defining material in the library
• Specimen is clamped as the boundary conditions
• Subject is to different loads produce by strain
• Perform the test for all three model of propellant
• Plot graph under each loads i.e displacement
• Analyze damage in material
• Calculate its mechanical properties
19

20. Geometry Generation and Boundary Conditions
Figure 8 Defining boundary conditions
20

21. Mesh Generation(wtd)
Figure 10 Mesh configurations of Specimen around
16000 micro elements
21

22. Damage Growth Model
Damage Growth Model helps to determine damage occurrence in a material.
Damage variable reflects the reduction ratio of stress due to Damage growth and denoted by D.
The continuum damage-mechanics-based definition for the damage variable can be expressed as, (Voyiadjis
and Kattan, 2009)
Where,
iis the stress in the propellant without damage
is the stress in the propellant with damage
Helps to validate the Computational Analysis (Damage occurance in material).
22

23. Tensile Test Monomodal
Tensile test is performed under different loading conditions i.e Displacement in our case.
Test on Mono modal:
• The displacement ranges from 10mm to 30mm.
• Deformation in material occurs at 5mm displacement.
• The stress strain curves are generated for all loads applied.
• Mechanical properties are calculated from them.
The Graph Plotted shown in next slide,
23

24. Tensile Analysis Monomodal
24
-5
0
5
10
15
20
25
30
35
40
45
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18
Stress
(Mpa)
Strain
Monomodal - Stress Vs Strain Curve
10mm
20mm
30mm

25. Tensile Analysis Monomodal
Displacement Stress max (Mpa) Strain max Damage / Failure
occur
2mm 12 0.019 No
5mm 20 0.039 No
10mm 25 0.058 No
20mm 33 0.076 Yes
30mm 39.5 0.095 Yes
Table 2 Tensile Analysis of Monomodal
25

26. Tensile Test Bimodal
Tensile test is performed under different loading conditions i.e Dispacement in our case.
Test on Bi modal:
• The displacement ranges from 20mm to 70mm.
• Value is higher as strength of Bi model is high.
• Deformation in material occurs at 40 mm displacement.
• The stress strain curves are generated for all displacement.
• Mechanical properties are calculated from them.
The Graph Plotted shown in next slide,
26

27. Tensile Analysis Bimodal
-5
0
5
10
15
20
25
30
35
40
45
50
-0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
Stress
(Mpa)
Strain (mm/mm)
Biomodal - Stress Vs Strain
20 mm
30 mm
40 mm
50 mm
60 mm
70 mm
27

28. Tensile Analysis Bimodal
Displacement Stress max (Mpa) Strain max Damage / Failure
occur
10mm 6.2 0.19 No
20mm 11.2 0.39 No
30mm 16.6 0.58 No
40mm 21.5 0.65 Yes
50mm 23.17 0.72 Yes
Table 3 Tensile Analysis of Bimodal
28

29. Tensile Test Trimodal
Tensile test is performed under different loading conditions i.e Displacement in our case.
Test on Tri modal:
• The displacement ranges from 10mm to 60mm.
• Strength of Tri model is more high than Bi modal.
• Deformation in material occurs at 60 mm displacement.
• The stress strain curves are generated for all displacement.
• Mechanical properties are calculated from them.
The Graph Plotted shown in next slide,
29

30. Tensile Analysis Trimodal
-10
0
10
20
30
40
50
-0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4
Stress
(Mpa)
Strain (mm/mm)
Trimodal- Stress Vs Strain
50 mm
60 mm
70 mm
30 mm
30

31. Tensile Analysis Trimodal
Displacement Stress max (Mpa) Strain max Damage / Failure
occur
10mm 9.32 0.225 No
20mm 15.2 0.39 No
30mm 19.65 0.58 No
40mm 21.5 0.65 No
60mm 34.6 0.85 Yes
Table 4 Tensile Analysis of Trimodal
31

32. Comparison of Mono Bio Tri modal
Now comparing the strength and other mechanical properties of all three models at the loads/displacement
where fracture in a material occurs.
Also compare with the experimental data obtained from research paper, by James Christopher Thomas in
2018 as ‘Mechanical Properties of Composite AP/HTPB Propellants Containing Novel
Titania Nanoparticles’
Graphs showing the comparisons are given as,
32

33. Comparison of Mono Bio Tri modal
-5
0
5
10
15
20
25
30
35
40
45
50
-0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
Stress
(Mpa)
Strain (mm/mm)
Mono Bio Tri- Stress Vs Strain
Monomodal
Biomodal
Trimodal
33

34. Results Validation from Numerical Analysis and Experimental data
Propellant
Grain
Config.
Density
(kg/mm3)
Modulus of
Elasticity
(Mpa)
ultimate
tensile
strength
(Mpa)
fracture
strength
(Mpa)
Modulus of
Resilience
(Joule/mm3)
Modulus of
Toughness
(Mpa)
Ductility (L
= 120 mm )
(%)
Monomodal 1.19E-07 32 40 33 550 1800 7.5
Bimodal 1.18E-06 34 42 38 630 3800 13
Trimodal 1.16E-05 39 49 35 700 4300 16
Monomodal
(Experimental
data)
34
(Error = 6.25 %)
6.8
(Error = 9.3 %)
Bimodal
(Experimental
data)
38
(Error = 9.7 % )
12
(Error = 8.3 %)
Trimodal
(Experimental
data)
42
(Error = 7.14 % )
15
(Error = 6.66
%)
34

35. Conclusion from the Test
 Modulus of Elasticity(E) of Trimodal is greater than all.
 Trimodal has maximum strength.
 E becomes constant after fracture have occurred in specimen.
 UTS is increasing as the displacement loading increases.
 UTS is approx 1.25 times of E
 Fracture Strength increase as tensile displacement increase also elongation area
increase with tensile displacement.
 Modulus of Resilience Ur decrease as increase tensile displacement
 Damage Growth Model helps to predict deformation occurrence in material.
35

36. ACCELERATED AGING (CREEP)
Accelerated is performed in order to check stress reduction in a Propellant after a certain period of time when
it is in store as fuel in rockets.
It is performed in following way,
• A material is heated to a temperature of 303 degree Kelvin.
• Constant pre strain as stress is applied on it for certain time different for all three models.
• The time period was 600 sec.
• Then material is removed from load and temp to cool down until its shape donot change.
• Tensile test is performed as in previous.
• Compare Non Age properties with Aged Material properties.
Creep test performed Analytically where as tensile test using Numerical modelling through ANSYS.
36

37. ACCELERATED AGING (CREEP)
Creep test is performed Analytically using the Kelvin-Voigt model because of viscoelastic material.
A Kelvin-Voigt model with single spring and single dashpot in parallel.
Using the initial condition (when, t = 0,
E =0 and 0 < t < 600 , stress = 𝜎 and strain = 𝜀 ) equation written as,
The differential equation can written as,
Where,
𝜂 = 𝐷𝑎𝑚𝑝𝑖𝑛𝑔 𝐶𝑜𝑛𝑠𝑡𝑎𝑛𝑡
𝐸 = 𝑆𝑝𝑟𝑖𝑛𝑔 𝐶𝑜𝑛𝑠𝑡𝑎𝑛𝑡
37
𝜀 =
𝜎
𝐸
[1 − 𝑒
𝐸
𝜂
𝑡
𝑑𝜀
𝑑𝑡
=
𝜎
𝜂
−
𝐸
𝜂
𝜀

38. ACCELERATED AGING (CREEP)
If the strain rate is plotted against the strain, is the slope and is the intercept.
From the research paper by Bipin K. Bihari, ” A Study on Creep Behavior of Composite Solid
Propellants Using the Kelvin-Voigt Model” Values are obtained as,
The average value of was found to be 0.0046 and may be considered to be independent of stress.
The equation of was found as,
Where,
C= 5,6 and 7
38
𝜎
𝜂
= 0.0002 ln 𝜎 + 𝐶 × 10−4

39. ACCELERATED AGING (CREEP)
Main purpose of creep test is to obtain residual stresses in a material which is then subjected to tensile
test.
The strain rate is calculated from the above equations under pre-strain and temperature, taken at the
deformation.
From this strain rate, multiplied by time i.e: 600 sec to obtain strain induced due to creep.
Stress is calculated from it.
After this, the tensile test is performed in order to comparison between aged and non aged.os
39

40. ACCELERATED AGING (CREEP)
40
FOR MOMO-MODAL:
Temp = 303 k
Time=600 sec
Relax time=1200 sec
Pre-strain= 24% (30 mm)
E= 32 Mpa
Stress applied= 7.68 Mpa
Strain after creep= 12%
By using applies stress and strain occur,
Residual strain=6.45%
Residual Stress= 2.194 Mpa

41. ACCELERATED AGING (CREEP)
41
-5
0
5
10
15
20
25
30
35
40
45
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14
Stress
(Mpa)
Strain
Accelerated VS Non Accelerated Aging (Monomodal)
NA
Ag

42. ACCELERATED AGING (CREEP)
42
FOR BI-MODAL:
Temp = 303 k
Time=600 sec
Relax time=1200 sec
Pre-strain= 36% (45 mm)
E= 38 Mpa
Stress applied= 13.68 Mpa
Strain after creep= 11%
By using applies stress and strain occur,
Residual strain=6%
Residual Stress= 2.28 Mpa

43. ACCELERATED AGING (CREEP)
43
-5
0
5
10
15
20
25
30
35
40
45
50
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
Stress
(Mpa)
Strain
Accelerated VS Non Accelerated Aging (Bimodal)
Nag
Ag

44. ACCELERATED AGING (CREEP)
44
FOR TRI-MODAL:
Temp = 303 k
Time=600 sec
Relax time=1200 sec
Pre-strain= 40% (55 mm)
E= 42 Mpa
Stress applied= 18.84 Mpa
Strain after creep= 9 %
By using applies stress and strain occur,
Residual strain= 5 %
Residual Stress= 2.1 Mpa

45. ACCELERATED AGING (CREEP)
45
-10
0
10
20
30
40
50
60
0 0.2 0.4 0.6 0.8 1 1.2
Stress
(Mpa)
Strain
Accelerated VS Non Accelerated Aging (Trimodal)
NAg
Ag

46. NON ACCELERATED AGING VS ACCELERATED AGING RESULTS
Propellant
Grain
Config.
Density
(kg/mm3)
Modulus of
Elasticity
(Mpa)
ultimate
tensile
strength
(Mpa)
fracture
strength
(Mpa)
Modulus of
Resilience
(Joule/mm3)
Modulus of
Toughness
(Mpa)
Ductility (L
= 120 mm )
(%)
Monomodal 1.19E-07 32 40 33 550 1800 7.5
Bimodal 1.18E-06 34 42 38 630 3800 13
Trimodal 1.16E-05 39 49 35 700 4300 16
Monomodal
(Accelerated
Aging)
-- 29 37 30 520 1600 6
Bimodal
(Accelerated
Aging)
-- 31 39 35 600 3500 10.5
Trimodal
(Accelerated
Aging)
-- 36 46 32 670 4000 13
46

47. CONCLUSION FOR THE TEST
47

48. SUSTAINABLE GOALS
48
Following goals are being directed by our project,
• Goal for Quality Education
• Affordable and Clean Energy
• Decent work and Economic Growth
• Responsible consumption and production

49. REFERENCES
• Voyiadjis, G.Z., Kattan, P.I., 2009. A comparative study of damage variables in
continuum damage mechanics. Int. J. Damage Mech. 18, 315–340 [1]
• Bipin K. Bihari, ” A Study on Creep Behavior of Composite SolidPropellants Using the
Kelvin-Voigt Model”
49

50. THANK YOU
50