buletinul institutului politehnic din iaşi - Universitatea Tehnică ...

More documents

Recommendations

Info

210 Ovidiu Niţă and Vasile Braha e1 e1 0.20 0.15 0.10 0.05 0.00 FLD variation for steel 0.5mm 0.05 0.10 e2 0.15 0.20 Variable Circular Eliptic Square e1 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0.00 FLD variation for steel 1mm 0.00 0.05 0.10 0.15 e2 0.20 0.25 0.30 a b Fig. 7 – FLD variation depending on active shape (steel): a – 0.5mm thickness specimens; b – 1mm thickness specimens. Variable Circular Eliptic Square After processing the experimental data was seen that the specimen’s thickness have a significantly influence, regarding the FLC position on graphs, only when using squares active plate. In other cases FLC position are very close and sometimes have tangent points (Fig. 8). 0.12 0.10 0.08 0.06 0.04 0.02 FLD variation - square active plate 0.000 0.025 0.050 e2 0.075 0.100 Variable 0.5 mm 1 mm e1 0.12 0.10 0.08 0.06 0.04 0.02 0.00 FLD variation - elliptical active plate 0.00 0.01 0.02 0.03 0.04 0.05 e2 0.06 0.07 0.08 0.09 a b Fig. 8 – FLD variation depending on specimen thickness (brass): a – square active plate shape; b – elliptical active plate shape. Variable 0.5 mm 1 mm It should be noted that, both experimental planning and graphs were obtained using Minitab V15 (trail version) software. 4. Conclusions 1. The research presented in this paper provided an opportunity to determine a mathematical relationship that characterizes the interdependence between the two principal strains ε1 and ε2. In all studied cases it was found that the best equation for describing the forming deformation curve is the second degree polynomial equation. 2. One of most important conclusions that deriving from this study is that, the use of elliptical and square active plate shapes can affect the accuracy of results. This can only lead to the hypothesis that, when using elliptical or square
Bul. Inst. Polit. Iaşi, t. LVIII (LXII), f. 4, 2012 211 active plates, a series of additional tangential efforts exceed the maximum allowable material limit. Thus, failure of material occurs before its maximum limit of deformation. 3. It should be noted that, the forming limit diagram obtained using hydraulic bulging test provides information only for the positive values of deformation. 4. The constructive solution made, for the experimental, tests may be a suitable facility for a research laboratory because of the simplicity of construction and high mobility. Acknowledgements. This paper was realized with the support of EURODOC “Doctoral Scholarships for research performance at European level” project, financed by the European Social Fund and Romanian Government. REFERENCES Assempour A. et al., A Methodology for Prediction of Forming Limit Stress Diagrams Considering the Strain Path Effect. Computational Materials Science, 45, 2, 195- 204 (2009); www.sciencedirect.com, accessed at 25.10.2009. Banabic D., Dörr, I.R., Deformabilitatea tablelor metalice subţiri. Metoda curbelor limită de deformare. Ed. OIDICM, Bucureşti, 1992. Banabic, D., Aretz H., Comşa D.S., Paraianu L., An Improved Analytical Description of Orthotropy in Metallic Sheets. International Journal of Plasticity, 21, 3, 493-512 (2005), source: www.sciencedirect.com, accessed at 20.01.2010. Banabic D., Modelarea curbelor limită de deformare, un nou instrument al fabricaţiei virtuale în procesele de deformare a tablelor metalice, raport cercetare. 2008; http://www.mcld.utcluj.ro/Raport_2008.pdf, accessed at 13.07.2010. Braha, V., Nagit, Gh., Negoescu, F., (2003), Tehnologia presarii la rece. Ed. CERMI, Iaşi. Bressan J.D., Influence of Thickness Size in Sheet Metal Forming. International Journal of Material Forming, 1, sup. 1, pp.117-119, source: www.springerlink.com, accessed at 26.02.2010. Marciniak Z., Duncan J.L., Hu S.J., Mechanics of Sheet Metal Forming (sec. Ed.), Butterworth-Heinemann, Oxford, 2002. *** http://www.eqsgroup.com/sheet-metal-forming-services/steel-formability-anal- ysis-training.asp; accessed at 10.09.2012. DETERMINAREA CURBELOR LIMITĂ DE DEFORMARE UTILIZÂND METODA UMFLĂRII HIDRAULICE (Rezumat) Principalul obiectiv în elaborarea lucrării propuse l-a constituit evaluarea modului în care curbele limită de deformare pot caracteriza capacitatea de deformare a unui material. De asemenea, în cadrul demersului s-a dorit identificarea şi studierea unor factori ce pot altera, sau nu, calitatea informaţiei transmise prin intermediul CLD, în condiţiile în care la ora actuală curba limită de deformare constituie cel mai utilizat
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: BULETINUL INSTITUTULUI POLITEHNIC D
Page 175 and 176: Bul. Inst. Polit. Iaşi, t. LVIII (
Page 181: Bul. Inst. Polit. Iaşi, t. LVIII (
Page 184 and 185: 172 Mariana Lupchian Propulsion eng
Page 186 and 187: 174 Mariana Lupchian Fig. 1 - The p
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 242 and 243: 230 Victor Cotoros and Emil Budescu
Page 273 and 274:
Page 275 and 276:
Page 277 and 278:
Page 279 and 280:
Page 281 and 282:
Page 283 and 284:
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?