1. A method for predicting an amount of dimensional accuracy defect at the time of performing a press-forming of a metal sheet comprising:
setting a stress-strain relationship with respect to said metal sheet based on an elastic-perfectly plastic solid material model having a constant stress value after being yielded;
formulating a first prediction equation of an amount of dimensional accuracy defect using said stress-strain relationship based on said elastic-perfectly plastic solid material model;
setting a value which is equal to or below a tensile strength and exceeds a yield strength as an apparent yield strength with respect to said metal sheet;
formulating a second prediction equation of an amount of dimensional accuracy defect which considers work hardening by replacing a portion of said first prediction equation of an amount of dimensional accuracy defect corresponding to said yield strength with said apparent yield strength; and
obtaining a dimensional accuracy defect amount using said second prediction equation of an amount of dimensional accuracy defect which considers work hardening.
2. The method for predicting an amount of dimensional accuracy defect according to claim 1, wherein said apparent yield strength is obtained by a following equation (1)
\u03c3p\u2032=k\xb7YS+(1\u2212k)TS\u2003\u2003(1)
where \u03c3p\u2032: apparent yield strength (MPa), YS: actually measured yield strength (MPa), TS: tensile strength (MPa), k: internal division coefficient.
3. The method for predicting an amount of dimensional accuracy defect according to claim 2, wherein said internal division coefficient k is set as a function of a ratio (TSt) between said tensile strength TS and said sheet thickness t.
4. The method for predicting an amount of dimensional accuracy defect according to claim 1, wherein an amount of dimensional accuracy defect which is subjected to a prediction is a wall warp amount at the time of performing press-forming and said second prediction equation of an amount of dimensional accuracy defect which considers work hardening for obtaining said wall warp amount is a following equation (2)
\u03c1={(3\u03c3p\u2032E\xb7t)}\xb7{1\u2212D\xb7(\u03c3TTS)\u22120.32}\u2212C\xb7(rd\u22125)\u2003\u2003(2)
where \u03c1=wall warp amount (curvature; 1mm), \u03c3p\u2032: apparent yield strength (MPa), E: Young’s modulus (MPa), t: sheet thickness (mm), TS: tensile strength (actually measured value;
MPa) \u03c3T: tension acting on wall portion (MPa), rd: radius of die shoulder of press forming tool (mm), C: constant(1mm2), D: constant.
5. The method for predicting an amount of dimensional accuracy defect according to claim 4, wherein said apparent yield strength is obtained by a following equation (3)
\u03c3p\u2032=k\xb7YS+(1\u2212k)TS\u2003\u2003(3)
where \u03c3p\u2032: said apparent yield strength (MPa), YS: actually measured yield strength (MPa), TS: tensile strength (MPa), k: internal division coefficient.
6. The method for predicting an amount of dimensional accuracy defect according to claim 5, wherein said internal division coefficient k is obtained based on a following equation (4)
k=A\xb7(TSt)+B\u2003\u2003(4)
where TS: said tensile strength, t: sheet thickness, A: negative constant (mmMPa), B: positive constant.
7. The method for predicting an amount of dimensional accuracy defect according to claim 1, wherein an amount of dimensional accuracy defect which is subjected to a prediction is an angular change amount at the time of performing press-forming and said second prediction equation of an amount of dimensional accuracy defect which considers work hardening for obtaining said angular change amount is comprised of following equations (5) and (6)
\u0394\u03b8=\u2212\u03b8\xb7(rp+t2)\xb7\u0394\u03c1\u2003\u2003(5)
\u0394\u03c1=(\u22123\u03c3p\u2032E\xb7t)\xb71+exp(\u2212G\xb7rp)\u2003\u2003(6)
where \u0394\u03b8: angular change amount (degree), \u03b8: bending angle (degree), rp: radius of shoulder of bending tool (mm), t: sheet thickness (mm), \u0394\u03c1: curvature change amount (1mm), \u03c3p\u2032: apparent yield strength (MPa), E: Young’s modulus (MPa), G: constant(mm).
8. The method for predicting an amount of dimensional accuracy defect according to claim 7, wherein said apparent yield strength is obtained by a following equation (7)
\u03c3p\u2032=k\xb7YS+(1\u2212k)TS\u2003\u2003(7)
where \u03c3p\u2032: said apparent yield strength (MPa), YS: actually measured yield strength (MPa), TS: tensile strength (MPa), k: internal division coefficient.
9. The method for predicting an amount of dimensional accuracy defect according to claim 8, wherein said internal division coefficient k is obtained based on a following equation (8)
k=A19 (TSt)+B\u2003\u2003(8)
where TS: said tensile strength (MPa), t: sheet thickness(1mm), A: negative constant (mmMPa), B: positive constant.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An ignition system for a gas turbine engine, comprising:
first and second ignition units;
first and second igniters;
first and second power supply busses for power (P1, P2);
first and second control units for activation of the power supplies:
wherein the first and second ignition units are connected respectively, to the first and second igniters, the first and second power supply busses for power (P1, P2), and the first and second control units
each power supply bus comprising a standard bus for power P1 and an emergency bus for power P2 and a relay, which in normal operation of the first power supply bus is electrically connected to the standard bus for power P1 and in normal operation of the second power supply bus is electrically connected to the emergency bus for power P2, and, wherein, in the event of a power supply failure, the respective relay makes an automatic switchover to the respective other power supply of the corresponding power supply bus.
2. An ignition system in accordance with claim 1, wherein the relays are arranged ahead of the ignition units.
3. An ignition system in accordance with claim 2, wherein individual lines of the standard bus and of the emergency bus are alternately arranged in the power supply bus.
4. An ignition system in accordance with claim 3, wherein the standard bus and the emergency bus in the second power supply bus are in mirrored arrangement as compared to the standard bus and the emergency bus in the first power supply bus.
5. An ignition system in accordance with claim 4, wherein the switchover is mechanically operated due to a deenergization of the respective relay.
6. An ignition system in accordance with claim 1, wherein the relays are respectively integrated into one of the ignition units or the control units.
7. An ignition system in accordance with claim 1, wherein individual lines of the standard bus and of the emergency bus are alternately arranged in the power supply bus.
8. An ignition system in accordance with claim 7, wherein the standard bus and the emergency bus in the second power supply bus are in mirrored arrangement as compared to the standard bus and the emergency bus in the first power supply bus.
9. An ignition system in accordance with claim 8, wherein the switchover is mechanically operated due to a deenergization of the respective relay.
10. An ignition system in accordance with claim 1, wherein the standard bus and the emergency bus in the second power supply bus are in mirrored arrangement as compared to the standard bus and the emergency bus in the first power supply bus.
11. An ignition system in accordance with claim 1, wherein the switchover is mechanically operated due to a deenergization of the respective relay.