buletinul institutului politehnic din iaşi - Universitatea Tehnică ...

More documents

Recommendations

Info

222 Petronela Paraschiv and Ciprian Paraschiv i) static shaping, when the system is in equilibrium, stable or unstable, without move; ii) cinematic shaping, when only the system movement is regarded, without taking into consideration the mechanical load (force and force moments) that produce the movement; iii) dynamic shaping, when the system movement is analysed taking into consideration all forces and moments that determine the movement. The analytical shaping generally behaves the following stages: physical or structural shaping, mathematical shaping, pysical or structural shaping supposes the formulation of a “physical model”, which behaviour is supposed to approximate as well as possible the one of the real system. The physical model resembles the real system concerning the basic characteristics, but it is simpler and therefore more approachable to the analysis. Therefore, the component elements of a biomechanical system can be shaped through solid bodies, rigid or elastic, bows, buffers etc., while the mutual action of two bodies can be drawn through concentrated forces, concentrated couples, distributed loads etc. (Budescu & Iacob, 2005). In many cases, the dynamic response of the biomechanical structures can be represented through a model with `concentrated parameters`, composed from masses, bows and buffers. The approximations done to the formulation of the physical models refer to: neglecting the secondary effects; neglecting some interactions with the environment; replacing the characteristics `distributed` through similar “concentrated” parameters; linearization of cause – effect relations between physical variables; neglecting the time variation of some parameters. Along the improvement of the model and of defining more precisely the problem analysed, one will give up part of these approximations. Mathematical shaping supposes the elaboration of a `mathematical model` that will represent the physical model, respectively the writing of the estate equations (cinematic, static, dynamic) of the physical system (Memislogu, 2003). Passing from the physical model to the mathematical model is realised through successive stages: i) choosing variables that describe the estate of the system at a given moment; ii) establishing the estate equations (for instance, equilibrium, static or dynamic equations) for the analysed system; iii) establishing the compatibility equations, which express the link between the moves of interconnected subsystems; iv) writing the physical laws, meaning the constitutive relationships for each component element of the system (Burnstein & Wright, 1994).
Bul. Inst. Polit. Iaşi, t. LVIII (LXII), f. 4, 2012 223 2. Numerical Results The stability of the mathematical model of a system, meaning the determination of the equation that govern its dynamic processes, can be done from more points of view, out of which, at least two are fundamental. The first one supposes that the system parameters as well as the signals (the stimulus) that act over it represent determinist sizes, i.e. sizes which evolution in time can be established if it is known their anterior evolution. A system governed by these kinds of laws is described through a determinist mathematical model and it is obvious that it should be studied easier than a system that would listen to the laws of hazard. Generally, those kinds of systems are analyzed for the `normal` estate of health of the shaped biomechanical system. The second point of view supposes that an indeterminist system cannot be described unless by static or probabilistic sizes. The equations that express in this case the system behaviour represent the probabilistic mathematical model. Such a biomechanical system is closer to traumatic or pathological states that can intervene at a given moment over the analysed subject. Articular rehabilitation at the level of the superior or inferior member of the human body, using either a mobile orthosis either a specially made mechanism for generating and controlling the movement of a certain body segment, supposes the knowledge of some values of the cinematic characteristics from the respective articulation (especially, the angular amplitude for active and passive moves), as well as date of the dynamic characteristics regar<strong>din</strong>g the force and moment of reaction from the articulation (Deitz, 2003). Normal articular amplitudes are the same, with small differences, irrelevant, for all individuals in the same age category, irrespective of sex or anthropometric data, while the reactions` torso from an articulation depends on the anthropometric sizes of the analysed subject and the state of mechanical load at which the considered body segment is subjected. This is why the static or dynamic analysis, after case, of a customized body biomechanical system is very important for the conception and realization of any technical system of articular rehabilitation for a passive move mainly (Elias et al., 2004; Hamilton & Luttgens, 2002). For solving the dynamic equations of the forearm, there are necessary more anthropometric sizes (segmentary lengths, masses, inertness moments etc), presented in Table 1. The numeric analysis was accomplished for a human subject with the height H = 1.71 m and weight M = 76 kg, for whom were determined the following anthropometric sizes, calculated accor<strong>din</strong>g to the relations in Table 1: Lb = 0.31806 m; Lab = 0.24966 m; Lab-m = 0.43092 m; Lms = 0.74898 m.
Page 1:
BULETINUL INSTITUTULUI POLITEHNIC D
Page 5 and 6:
Page 7:
VICTOR COTOROS şi EMIL BUDESCU, As
Page 10 and 11:
ALEXANDRU RADU, CONSTANTIN PANĂ an
Page 13 and 14:
Page 15 and 16:
Bul. Inst. Polit. Iaşi, t. LVIII (
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39:
Page 42 and 43:
30 Daniel Dragomir-Stanciu and Mari
Page 44 and 45:
32 Daniel Dragomir-Stanciu and Mari
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61:
Page 64 and 65:
52 Ionel Oprea and low viscosity ar
Page 66 and 67:
54 Ionel Oprea COP PT Puterea speci
Page 68 and 69:
56 Ionel Oprea 8. GWP - global warm
Page 70 and 71:
58 Ionel Oprea suplimentari, cum ar
Page 72 and 73:
60 Răzvan Florin Barzic et al. Cur
Page 74 and 75:
62 Răzvan Florin Barzic et al. 3-
Page 76 and 77:
64 Răzvan Florin Barzic et al. 3.
Page 78 and 79:
66 Ionel Ivancu et al. the second s
Page 80 and 81:
68 Ionel Ivancu et al. a b Fig. 4 -
Page 82 and 83:
70 Ionel Ivancu et al. Gut J.A.W.,
Page 84 and 85:
72 Ion Zabet and Graţiela-Maria Ţ
Page 86 and 87:
Page 88 and 89:
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
82 Victor Pantilie et al. many rese
Page 96 and 97:
84 Victor Pantilie et al. industria
Page 98 and 99:
86 Victor Pantilie et al. Another i
Page 100 and 101:
88 Victor Pantilie et al. At the en
Page 102 and 103:
90 Victor Pantilie et al. Tang X.,
Page 104 and 105:
92 Alexandru Radu et al. Furthermor
Page 106 and 107:
94 Alexandru Radu et al. Spark timi
Page 108 and 109:
96 Alexandru Radu et al. Fig. 3 - B
Page 110 and 111:
98 Alexandru Radu et al. 4. The bes
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127:
Page 130 and 131:
118 Eugen Rusu et al. in PM emissio
Page 132 and 133:
120 Eugen Rusu et al. also be used
Page 134 and 135:
122 Eugen Rusu et al. Fig. 3 - Maxi
Page 136 and 137:
124 Eugen Rusu et al. Fig. 6 - HC e
Page 138 and 139:
126 Eugen Rusu et al. Pe lângă ce
Page 140 and 141:
128 Adrian Sabău et al. arguments
Page 142 and 143:
130 Adrian Sabău et al. The energy
Page 144 and 145:
132 Adrian Sabău et al. during fue
Page 146 and 147:
134 Adrian Sabău et al. 11 T ⎛ 0
Page 148 and 149:
136 Adrian Sabău et al. No experim
Page 150 and 151:
138 Adrian Sabău et al. calculated
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163:
Page 166 and 167:
154 Marius Receanu et al. where: qr
Page 168 and 169:
156 Marius Receanu et al. In Fig. 2
Page 170 and 171:
158 Marius Receanu et al. the ambie
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181:
Page 184 and 185: 172 Mariana Lupchian Propulsion eng
Page 186 and 187: 174 Mariana Lupchian Fig. 1 - The p
Page 189 and 190: BULETINUL INSTITUTULUI POLITEHNIC D
Page 191 and 192: Bul. Inst. Polit. Iaşi, t. LVIII (
Page 197: Bul. Inst. Polit. Iaşi, t. LVIII (
Page 200 and 201: 188 Costică Atanasiu et al. comput
Page 202 and 203: 190 Costică Atanasiu et al. γ= ε
Page 204 and 205: 192 Costică Atanasiu et al. The sa
Page 206 and 207: 194 Costică Atanasiu et al. Fig. 1
Page 208 and 209: 196 Costică Atanasiu et al. elasti
Page 210 and 211: 198 Ovidiu Niţă et al. rejection
Page 212 and 213: 200 Ovidiu Niţă et al. aluminium
Page 214 and 215: 202 Ovidiu Niţă et al. a b Fig. 5
Page 216 and 217: 204 Ovidiu Niţă et al. căreia ac
Page 218 and 219: 206 Ovidiu Niţă and Vasile Braha
Page 226 and 227: 214 Marian Teodor Popescu et al. 2.
Page 228 and 229: 216 Marian Teodor Popescu et al. Sp
Page 230 and 231: 218 Marian Teodor Popescu et al. Th
Page 233: BULETINUL INSTITUTULUI POLITEHNIC D
Page 239: Bul. Inst. Polit. Iaşi, t. LVIII (
Page 242 and 243: 230 Victor Cotoros and Emil Budescu
Page 285 and 286:
Page 287 and 288:
Page 289 and 290:
Page 291 and 292:
Page 293 and 294:
Page 295 and 296:
Page 297 and 298:
PC Cell calibration Bul. Inst. Poli
Page 299 and 300:
Page 301 and 302:
Page 303 and 304:
Page 305 and 306:
Page 307 and 308:
Page 309 and 310:
Page 311 and 312:
Page 313 and 314:
Page 315 and 316:
Page 317:
show all

buletinul institutului politehnic din iaşi - Universitatea Tehnică ...

Create successful ePaper yourself

Delete template?

Save as template?