COMPUTER ASSIGNMENT ME 270 BY VAMSHI KRISHNA REDDY CHADA

PROJECT AIM An engineering model and a bond graph model of the car,person,seat belts,bumper needs to be created and to transform the engineering model to of reality into a computer model for simulation using the Computer Aided Modeling Program CAMP-G.Then to perform interactive simulation and generate numerical and graphical output using MATLAB and considering the design criteria.

INITIAL CONDITIONS The given initial conditions for the problem are DATA ON INJURIES Seat belts must be tested to 3000lbs(1.334*104 N)‏ Chest can sustain a force of 1500lbs Chest area is 30 in^2 Seat belt effective area=30in^2 Shoulder strap seat belt combination=60in^2

PHYSICAL PARAMETERS Mass of car(M)=1500kg Mass of dummy(m)=100kg Bumper spring constant(k1)=10000N/m Bumper damping constant(R1)=500N-s/m Seat belt spring constant(K2)=300000N/m Seat belt damping constant(R2)=80000N-s/m

PROBLEM 1 solution procedure The objective of the problem is to find out weather dummy will hit the windshield or not when he travels at velocities 25mph and 55mph.In order to solve this the following steps should be followed. 1.The initial step is to draw the bond graph for given model by using CAMPG software. 2.Then bond graph model drawn in CAMPG is to be interface with MATLAB. 3.Then by interfacing with MATLAB it will get four files namely campgequ.m, campgmod.m,campgsym.m,campgnum.m. 4. The next step is to take campgmod.m file and required conditions for solving problem has to be initialized as follows -First the input variables has to be initialized in that file i.e..

dummy_mass=100; (Given mass of the dummy in kilograms)‏ car_mass=1500; (Given mass of the car in kilograms) mph= ; (Conversion factor to convert mph to meter per seconds)‏ v1=25*mph; (velocity component)‏ v1=55*mph; (Velocity component)‏ - Then a for loop is to be initialized in order to find weather at given velocities the dummy hit windshield or not. The initialization of for loop as follows. “ For i=1:2 vel=V(1,i)” Explanation of loop:By running for loop first 'i ' takes the value of '1' and then it takes the velocity V1 and in the next cycle ' i ' takes the value of ' 2 ' then it takes the velocity V2,then for both velocity components the pro gramme will run in the MATLAB. -Initial conditions in the campgmod.m file has to be given. -Then physical parameters must be declared in the campgmod.m file. -Then external inputs i.e source of flow must be initialized as ' 0 ' because the windshield doesn't move. -The time variables must be declared so that simulation period can be contolled within a limited period.

-Then in the next step maximum absolute displacement covered by the car and the dummy has to be taken from the graph obtained by the MATLAB program. -Then maximum displacement obtained are compared with 100cm(i.e displacement between car and windshield as given) by initializing 'if statement' in campgmod.m file and the program statements has to declared as shown in campgmod.m file which is attached to report. 5.The next step is to run the MATLAB file by clicking the debug icon. 6.Then we get the output or result as follows.... -At velocity 25mph dummy will not hit the windshield. -At velocity 55mph dummy will hit the windshield. 7.We also get the simulation graphs for velocities 25 mph and 55 mph.

PROBLEM 2 PART 1 SOLUTION PROCEDURE The objective of the problem is to find out the force acting on the chest of the dummy at 25mph and 55mph and to compare those forces with the given data and to know weather chest injury occurs or not when he wears seat belt only. The solution is as follows 1.The initial step is to draw the bond graph for given model by using CAMPG software. 2.Then bond graph model drawn in CAMPG is to be interface with MATLAB. 3.Then by interfacing with MATLAB it will get four files namely campgequ.m, campgmod.m,campgsym.m,campgnum.m. 4. The next step is to take campgmod.m file and required conditions for solving problem has to be initialized as follows -First the input variables has to be initialized in that file i.e..

dummy_mass=100; (Given mass of the dummy in kilograms)‏ car_mass=1500; (Given mass of the car in kilograms) mph= ; (Conversion factor to convert mph to meter per seconds)‏ v1=25*mph; (velocity component)‏ v1=55*mph; (Velocity component)‏ - Then a for loop is to be initialized in order to find weather at given velocities the dummy hit windshield or not. The initialization of for loop as follows. “ For i=1:2 vel=V(1,i)” Explanation of loop:By running for loop first 'i ' takes the value of '1' and then it takes the velocity V1 and in the next cycle ' i ' takes the value of ' 2 ' then it takes the velocity V2,then for both velocity components the pro gramme will run in the MATLAB. -Initial conditions in the campgmod.m file has to be given. -Then physical parameters must be declared in the campgmod.m file. -Then external inputs i.e source of flow must be initialized as ' 0 ' because the windshield doesn't move. -The time variables must be declared so that simulation period can be contolled within a limited period.

-Then by taking if statement we have to check weather maximum absolute force is greater than or equal to given maximum force on the chest i.e 6700 N. -Then we have to run the if loop by the variable ‘ i ‘ and to check weather chest injury occur or not at 25mph and 55mph 5.The next step is to run the MATLAB file by clicking the debug icon. 6.The output of the MATLAB program is -Force acting on the dummy at velocity 25mph is N. -Force acting on the dummy at velocity 55mph is N. 7.We also get the simulation graphs for velocities 25 mph and 55 mph.

PROBLEM 2 PART 2 SOLUTION PROCEDURE The objective of the problem is to find out the force acting on the chest of the dummy at 25mph and 55mph and to compare those forces with the given data and to know weather chest injury occurs or not when he wears seat belt and also the shoulder strap. The solution is as follows 1.The initial step is to draw the bond graph for given model by using CAMPG software. 2.Then bond graph model drawn in CAMPG is to be interface with MATLAB. 3.Then by interfacing with MATLAB it will get four files namely campgequ.m, campgmod.m,campgsym.m,campgnum.m. 4. The next step is to take campgmod.m file and required conditions for solving problem has to be initialized as follows -First the input variables has to be initialized in that file i.e..

dummy_mass=100; (Given mass of the dummy in kilograms)‏ car_mass=1500; (Given mass of the car in kilograms) mph= ; (Conversion factor to convert mph to meter per seconds)‏ v1=25*mph; (velocity component)‏ v1=55*mph; (Velocity component)‏ - Then a for loop is to be initialized in order to find weather at given velocities the dummy hit windshield or not. The initialization of for loop as follows. “ For i=1:2 vel=V(1,i)” Explanation of loop:By running for loop first 'i ' takes the value of '1' and then it takes the velocity V1 and in the next cycle ' i ' takes the value of ' 2 ' then it takes the velocity V2,then for both velocity components the pro gramme will run in the MATLAB. -Initial conditions in the campgmod.m file has to be given. -Then physical parameters must be declared in the campgmod.m file. -Then external inputs i.e source of flow must be initialized as ' 0 ' because the windshield doesn't move. -The time variables must be declared so that simulation period can be contolled within a limited period.

-Then by taking if statement we have to check weather maximum absolute force is greater than or equal to given maximum force on the chest i.e 6700 N. -Then we have to run the if loop by the variable ‘ i ‘ and to check weather chest injury occur or not at 25mph and 55mph by weaing seat belt and shoulder strap 5.The next step is to run the MATLAB file by clicking the debug icon. 6.The output of the MATLAB program is -Chest injury will occur at velocity 25mph. -Chest injury will occur at velocity 55mph. 7.We also get the simulation graphs for velocities 25 mph and 55 mph.

PRBLEM 3 SOLUTION PROCEDURE The objective of the problem is to find out the critical maximum velocity at which impact occurs at which hitting the windshield, chest injury,ineternal injury,seat belt failur,strap failure should not occur. The solution is as follows. 1.The initial step is to draw the bond graph for given model by using CAMPG software. 2.Then bond graph model drawn in CAMPG is to be interface with MATLAB. 3.Then by interfacing with MATLAB it will get four files namely campgequ.m, campgmod.m,campgsym.m,campgnum.m. 4. The next step is to take campgmod.m file and required conditions for solving problem has to be initialized as follows -First the input variables has to be initialized in that file i.e..

dummy_mass=100; (Given mass of the dummy in kilograms)‏ car_mass=1500; (Given mass of the car in kilograms) mph= ; (Conversion factor to convert mph to meter per seconds)‏ v1=25*mph; (velocity component)‏ v2=55*mph; (Velocity component)‏ - Then a for loop is to be initialized in order to find out the critical maximum velocity. “ For i=1:55 vel_mps=i*mph Explanation of loop:By running for loop first 'i ' takes the value of '1' and gradually increase the ‘I’ value and checks for maximum critical velocity. -Initial conditions in the campgmod.m file has to be given. -Then physical parameters must be declared in the campgmod.m file. -Then external inputs i.e source of flow must be initialized as ' 0 ' because the windshield doesn't move. -The time variables must be declared so that simulation period can be contolled within a limited period

-Then by taking if statement we have to check weather maximum absolute force is greater than or equal to given maximum force on the chest i.e 6700 N and 5500N. -Then we have to run the if loop by the variable ‘ i ‘ and to find out the critical maximum velocity 5.The next step is to run the MATLAB file by clicking the debug icon. 6.The output of the MATLAB program is -Displacement of dummy at critical maximum velocity=0.4778meters -Force exerted on dummy at critical maximum velocity= newtons -Critical maximum velocity=16mph 7.We also get the simulation graphs for maximum critical velocity.

PROBLEM 4 SOLUTION PROCEDURE The objective of the problem is to find out the time and force acting on dummy when he hits the windshield at velocities 25mph,40mph and 55mph without wearing seat belt. The solution is as follows. 1.The initial step is to draw the bond graph for given model by using CAMPG software. 2.Then bond graph model drawn in CAMPG is to be interface with MATLAB. 3.Then by interfacing with MATLAB it will get four files namely campgequ.m, campgmod.m,campgsym.m,campgnum.m. 4. The next step is to take campgmod.m file and required conditions for solving problem has to be initialized as follows -First the input variables has to be initialized in that file i.e..

dummy_mass=100; (Given mass of the dummy in kilograms)‏ car_mass=1500; (Given mass of the car in kilograms) mph= ; (Conversion factor to convert mph to meter per seconds)‏ v1=25*mph; (velocity component)‏ v2=40*mph; (Velocity component)‏ v3=55mph, (velocity component) - Then a for loop is to be initialized in order to find out the time and force acting on the dummy at given velocities when he travels without seat belt. “ For i=1:3 vel=V(1,i) Explanation of loop:By running for loop first 'i ' takes the value of '1' and gradually increase the ‘I’ value and gives the time and force at which dummy hits windshield by testing if loops in prior statements in the mat lab programme. -Initial conditions in the campgmod.m file has to be given. -Then physical parameters must be declared in the campgmod.m file. -Then external inputs i.e source of flow must be initialized as ' 0 ' because the windshield doesn't move. -The time variables must be declared so that simulation period can be contolled within a limited period

-Then by taking if statement we have to obtain time by dividing distance over corresponding velocity. -Then we have to run the if loop by the variable ‘ i ‘ and to find out the critical maximum velocity 5.The next step is to run the MATLAB file by clicking the debug icon. 6.The output of the MATLAB program is -Time taken by dummy to hit windshield at 25mph= Time taken by dummy to hit windshield at 40mph= Time taken by dummy to hit windshield at 55mph=

END OF THE REPORT BY CHADA,VAMSHI KRISHNA REDDY