|
|
马上注册，结交更多好友，享用更多功能，让你轻松玩转社区。
您需要 登录 才可以下载或查看，没有账号？我要加入
x
这是NewMark程序
- %NewMark Function
- clc,clear
- m1=341; % Quality of the former landing gear
- m2=363; % Quality of the back landing gear
- mc=24900; % Quality of the body
- Jc=424378; % Moment of inertia of the body
- Lz=5.805; % Distance between the former and the back tyre（m
- a=0.91*Lz; % Distance of the formwe tyre spread
- b=0.09*Lz; % Distance of the back tyre spread
- k1=8.1123e5; % Rigidity coefficient of the former tyre
- c1=3*1e4; % Damp coefficient of the former tyre
- k3=1.6285e5; % Rigidity coefficient of the former Amortine shoring
- c3=5*1e4; % Damp coefficient of the former Amortine shoring
- k2=4.41046; % Rigidity coefficient of the back tyre
- c2=3*1e4; % Damp coefficient of the back tyre
- k4=7.3361e5; % Rigidity coefficent of the back Amortine shoring
- c4=5*1e4; % Damp coefficient of the back Amortine shoring
- g=9.81;
- M = [(mc*b^2+Jc)/Lz^2 (mc*a*b-Jc)/Lz^2 0 0
- (mc*a*b-Jc)/Lz^2 (mc*a^2+Jc)/Lz^2 0 0
- 0 0 m1 0
- 0 0 0 m2];
- C = [c4 0 -c4 0
- 0 c3 0 -c3
- -c4 0 c2+c4 0
- -c3 0 0 c1+c3];
- K = [k4 0 -k4 0
- 0 k3 0 -k3
- -k4 0 k2+k4 0
- -k3 0 0 k1+k3];
- u=[0 0 0 0]';
- v=[0 0 0 0]';
- a=[g 0 g g]';
- t(1)=0; %time
- x(:,1)=u; %distance
- x1(:,1)=v; %speed
- x2(:,1)=a; %accelerrate
- %newmar kcoefficient
- gama=0.5;
- dt=1e-2;
- delta=0.25;
- b0=1/(delta*dt^2);
- b1=gama/(delta*dt);
- b2=1/(delta*dt);
- b3=1/(2*delta)-1;
- b4=gama/delta-1;
- b5=dt*(gama/(2*delta)-1);
- b6=dt*(1-gama);
- b7=gama*dt;
- %等效刚度矩阵
- K1=K+b0*M+b1*C;
- t_max=10; %计算时间总长
- i=1;
- t(1)=0.01;
- q=zeros(4,1);
- while t(i)<t_max
- Q(:,i)=[0,0,0,0]';
- q(:,i+1)=Q(:,i)+M*(b0*x(:,i)+b2*x1(:,i)+b3*x2(:,i))+C*(b1*x(:,i)+b4*x1(:,i)+b5*x2(:,i));
- x(:,i+1)=inv(K1)*q(:,i+1);
- x2(:,i+1)=b0*(x(:,i+1)-x(:,i))-b2*x1(:,i)-b3*x2(:,i);
- x1(:,i+1)=b1*(x(:,i+1)-x(:,i))-b4*x1(:,i)-b5*x2(:,i);
- i=i+1;
- t(i)=t(i-1)+dt;
- end
这是wilson_cita程序
- %wilson_cita Function
- clc,clear
- m1=341; % Quality of the former landing gear
- m2=363; % Quality of the back landing gear
- mc=24900; % Quality of the body
- Jc=424378; % Moment of inertia of the body
- Lz=5.805; % Distance between the former and the back tyre（m
- a=0.91*Lz; % Distance of the formwe tyre spread
- b=0.09*Lz; % Distance of the back tyre spread
- k1=8.1123e5; % Rigidity coefficient of the former tyre
- c1=3*1e4; % Damp coefficient of the former tyre
- k3=1.6285e5; % Rigidity coefficient of the former Amortine shoring
- c3=5*1e4; % Damp coefficient of the former Amortine shoring
- k2=4.41046; % Rigidity coefficient of the back tyre
- c2=3*1e4; % Damp coefficient of the back tyre
- k4=7.3361e5; % Rigidity coefficent of the back Amortine shoring
- c4=5*1e4; % Damp coefficient of the back Amortine shoring
- g=9.81;
- M = [(mc*b^2+Jc)/Lz^2 (mc*a*b-Jc)/Lz^2 0 0
- (mc*a*b-Jc)/Lz^2 (mc*a^2+Jc)/Lz^2 0 0
- 0 0 m1 0
- 0 0 0 m2];
- C = [c4 0 -c4 0
- 0 c3 0 -c3
- -c4 0 c2+c4 0
- -c3 0 0 c1+c3];
- K = [k4 0 -k4 0
- 0 k3 0 -k3
- -k4 0 k2+k4 0
- -k3 0 0 k1+k3];
- u=[0 0 0 0]';
- v=[0 0 0 0]';
- a1=[g 0 g g]';
- t(1)=0; %time
- x(:,1)=u; %distance
- x1(:,1)=v; %speed
- x2(:,1)=a1; %accelerate
- %cita coeffi
- cita=1.42085;
- dt=1e-2;
- s=cita*dt;
- %等效刚度矩阵
- K1=K+6/s^2*M+3/s*C;
- t_max=10; %full time
- i=1;
- t(1)=0.01;
- while t(i)<t_max
- Q=[mc*g,0,m1*g,m2*g]';
- gt=M*(6/s^2*x(:,i)+6/s*x1(:,i)+2*x2(:,i))+C*(3/s*x(:,i)+2*x1(:,i)+s/2*x2(:,i))+Q;
- us=inv(K1)*gt;
- u2s=6/s^2*(us-x(:,i))-6/s*x1(:,i)-2*x2(:,i);
- u1s=3/s*(us-x(:,i))-2*x1(:,i)-s/2*x2(:,i);
- x2(:,i+1)=6*dt/s^3*(us-x(:,i))-6*dt/s^2*x1(:,i)+(1-3/cita)*x2(:,i);
- x1(:,i+1)=x1(:,i)+dt/2*(u2s-x2(:,i));
- x(:,i+1)=x(:,i)+dt*x1(:,i)+dt^2/6*(u2s+2*x2(:,i));
- i=i+1;
- t(i)=t(i-1)+dt;
- end
两个程序计算结果相差很大，希望大家帮忙看看。
其中NewMark程序算出稳定解
而wilson_cita算出的竟然不稳定 |
|
发表于 2006-11-15 12:47
提升卡
变色卡
显身卡
楼主