PhD Fekete - SZIE version - 2.2 - Szent István Egyetem

More documents

Recommendations

Info

Materials and Methods One problematic issue, that although the MSC.ADAMS program should accept several graphic files like IGS, STEP or PARASOLID, practically only the PARASOLID works properly. PARASOLID files can be created in Solid Edge or Solid Works software. Unfortunately, these software cannot convert STL files. Theoretically, the solution is the following: 1. The obtained raw STL files have to be repaired (holes, singularities) and then converted into IGS files with the Catia software. 2. The IGS files have to be converted into PARASOLID format by the use of the Solid Edge/Works software. Practically, some other factors – inside the CAD software – have to be taken into consideration in order to evade the upcoming errors in the file import process. This method was carried out in Solid Edge V16 and Catia V5R17, and it is systematically explained in the Appendix. 3.6.4. Multibody models After creating the geometrical models, multibody models were built with MSC.ADAMS program system. The following boundary conditions were applied on each model (Prosthesis 1, 2, 3, 4, 5) identically: − − Only the patellar tendon and the rectus femoris were considered in the numerical model. Both of them were modeled as simple linear springs (SPRING element see Figure 3.32). According to the literature, the stiffness coefficient of the rectus femoris can be found between 15 and 83 N/mm [Conceição et al., 2002, Thelen et al., 2005], therefore this parameter was set to 40 N/mm, as an average value, while a damping coefficient of 0.15 Ns/mm was attributed to all tendons to prevent oscillations in the system [Frigo et al., 2010, Granata et al., 2002]. The patellar tendon was set to inextensible. A FORCE VECTOR was applied on the femur distalis (Figure 3.32) which represented the load of the body weight (BW). The magnitude was set to 800 N (1 BW). The application of the vector was defined by a STEP function (STEP (A, x 0 , h 0 , x 1 , h 1 )), which means that the force magnitude proportionally increased in a certain period of time (STEP (time, 0.0, 0.0, 0.03, -800)) until it reached its maximum value (Figure 3.31). By loading the model with this method, initial unbalances could be evaded. Figure 3.31. Step function in MSC.ADAMS – 110 –
Materials and Methods − − − − The femur distalis was constrained by a GENERAL POINT MOTION, where all the coordinates can be prescribed (Figure 3.32). Only one prescription was set: the endpoint of the femur (distalis) can only perform translational motion along the y-axis. The ankle part of the model was constrained by a SPHERICAL JOINT, which allows rotation about all axes, but no translational motions are permitted in that point (Figure 3.32). By applying this constraint, the tibia can perform a natural rotation and a kinematic analysis can be carried out in a further study. Between the femur, tibia and patella, CONTACT constraints were set according to Coulomb’s law with respect to the very low static and dynamic friction coefficients (µ s = 0.003, µ d = 0.001) similarly to real joints [Mow and Soslowsky, 1991, Quian et al., 2006] (Figure 3.32). With this constraint, the kinetic relationship between the normal and friction forces (F n , F s ) and the flexion angle can be analyzed. The following material properties were set [Guess and Maletsky, 2004]: Young modulus Femur : 19 GPa, Poisson ratio Femur : 0.3, Young modulus Tibia : 1 GPa, Poisson ratio Tibia : 0.46. The material properties are necessary if CONTACT is used between the surfaces (see in CONTACT section). Figure 3.32. Multibody model in the MSC.ADAMS – 111 –
Page 1 and 2:
SZENT ISTVÁN UNIVERSITY KINETICS A
Page 3 and 4:
CONTENTS NOMENCLATURE AND ABBREVIAT
Page 5 and 6:
NOMENCLATURE AND ABBREVIATIONS F pf
Page 7 and 8:
ψ : Angle between the quadriceps t
Page 9 and 10:
v CTt : Tangential velocity compone
Page 11 and 12:
Introduction 1. INTRODUCTION AND OB
Page 13 and 14:
1.3. Aims of the PhD thesis Introdu
Page 15 and 16:
Literature review 2. LITERATURE REV
Page 17 and 18:
Literature review Figure 2.3. The f
Page 19 and 20:
Literature review Figure 2.6. Patel
Page 21 and 22:
Literature review Figure 2.8. Compo
Page 23 and 24:
Literature review The knee carries
Page 25 and 26:
Literature review For this reason,
Page 27 and 28:
Literature review Figure 2.12. Thre
Page 29 and 30:
Literature review As a short overvi
Page 31 and 32:
Literature review Moment arm 60 [mm
Page 33 and 34:
Literature review I. They demonstra
Page 35 and 36:
Literature review The presented mod
Page 37 and 38:
Literature review ε angle [˚] 100
Page 39 and 40:
Literature review Fpf/Fq [-] 1.2 1
Page 41 and 42:
Literature review β angle [˚] Mal
Page 43 and 44:
Literature review Figure 2.35. Mech
Page 45 and 46:
Literature review Moment arm 60 [mm
Page 47 and 48:
Literature review Let us follow the
Page 49 and 50:
Literature review Finally, the pate
Page 51 and 52:
Literature review Figure 2.43. Tota
Page 53 and 54:
Literature review One great advanta
Page 55 and 56:
Literature review Implant wear is t
Page 57 and 58:
2.3.2. General numerical models Lit
Page 59 and 60:
a) The tibia plateau is a flat surf
Page 61 and 62:
Literature review From their calcul
Page 63 and 64: Literature review Although a simila
Page 65 and 66: Literature review Slide/Roll [-] 1
Page 67 and 68: Literature review Figure 2.62. Mult
Page 69 and 70: Materials and Methods 3.1. Methodol
Page 71 and 72: Materials and Methods For the sake
Page 73 and 74: Materials and Methods 9 th QUESTION
Page 75 and 76: Materials and Methods 3.3. New anal
Page 77 and 78: Materials and Methods 3.3.3. Free-b
Page 79 and 80: Materials and Methods Figure 3.6. F
Page 81 and 82: Materials and Methods By the introd
Page 83 and 84: Materials and Methods 3.4. Experime
Page 85 and 86: Materials and Methods Figure 3.7. C
Page 87 and 88: Materials and Methods All of the pa
Page 89 and 90: Materials and Methods 3.4.5. Measur
Page 91 and 92: x c Materials and Methods ∑ Fi
Page 93 and 94: Materials and Methods Probability D
Page 95 and 96: Materials and Methods Figure 3.18.
Page 97 and 98: Materials and Methods By doing so,
Page 99 and 100: 3.4.7.2. Steps of the approach Mate
Page 101 and 102: Materials and Methods All the funct
Page 103 and 104: Materials and Methods β [º] 40 20
Page 105 and 106: Materials and Methods If the center
Page 107 and 108: Materials and Methods By the use of
Page 109 and 110: Materials and Methods Thus, one pri
Page 111 and 112: Materials and Methods I. The patter
Page 113: 3.6.3. Geometrical models Materials
Page 117 and 118: 3.6.4.3. Contact [MSC.ADAMS] Materi
Page 119 and 120: Materials and Methods Besides the k
Page 121 and 122: Materials and Methods By multiplyin
Page 123 and 124: Results 4. RESULTS 4.1. Results reg
Page 125 and 126: Results This closely equal percenta
Page 127 and 128: Results Fpf/BW [-] 8 Fekete et al.
Page 129 and 130: Results In reality, human subjects
Page 131 and 132: Results 4.2. Results regarding the
Page 133 and 134: Results 0.8 Χ [-] 1 Sliding-rollin
Page 135 and 136: Results Χ [-] 1 Sliding-rolling ra
Page 137 and 138: Results Among the tested prostheses
Page 139 and 140: Results χ [-] 1 Averaged sliding-r
Page 141 and 142: Results Χ [-] 1 Sliding-rolling ra
Page 143 and 144: 4.3. New scientific results Results
Page 145 and 146: Results 3 rd Thesis: Based on the m
Page 147 and 148: Conclusions and Suggestions 5. CONC
Page 149 and 150: Conclusions and Suggestions Suggest
Page 151 and 152: Summary 6. SUMMARY In this doctoral
Page 153 and 154: Appendix APPENDIX A1. Bibliography
Page 155 and 156: Appendix [31] Csizmadia B. M., Nán
Page 157 and 158: Appendix [61] Gill H. S., O’Conno
Page 159 and 160: Appendix [93] Klebanov B. M., Barla
Page 161 and 162: Appendix [123] Nägerl H., Frosch K
Page 163 and 164: Appendix [154] Reuben J. D., McDona
Page 165 and 166:
Appendix [187] Wahrenberg H., Lindb
Page 167 and 168:
Appendix 6. Fekete G., Kátai L.: M
Page 169 and 170:
Appendix Figure 3. Setting Stitchin
Page 171 and 172:
Appendix Fpf/Fq [-] 1.2 h = 6 mm h
Page 173 and 174:
Appendix η1 angle [˚] 6 Hirokawa
Page 175 and 176:
Appendix Figure 13. Mechanical mode
Page 177 and 178:
Appendix Ψ angle [˚] 10 Van Eijde
Page 179 and 180:
Appendix Figure 19. Mechanical mode
Page 181 and 182:
Appendix - 177 -
show all

PhD Fekete - SZIE version - 2.2 - Szent István Egyetem

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?