Introduction of Chassis Frame: Chassis is a French term and was initially used to denote the frame parts or Basic Structure of the vehicle. It is the back bone. In automotive engineering, the bodywork of an automobile is the structure which carriages, and had body-on-frame construction with a wooden frame and. Vehicle Body Engineering - Free download as PDF File .pdf), Text File .txt) or read online for free.
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Vehicle Body Engineering book. Read 17 reviews from the world's largest community for readers. Benefits of attending this course. The course will give invaluable information to participants who are interested in Vehicle Body Engineering. At the end of the. Course Description & Objectives: To develop the basic knowledge of the students in design of the vehicles body to give maximum comfort for the passengers.
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Community Reviews. Showing Rating details. Sort order. Apr 06, Soham Dave added it. View all 4 comments. Sep 20, Taufik Riyana added it. View 1 comment. Dec 23, Vipin Das marked it as to-read. Apr 27, Ankit rated it it was amazing. Conversely, if the ECU detects a wheel turning significantly faster than the others, brake hydraulic pressure to the wheel is increased so the braking force is reapplied, slowing down the wheel.
This process is repeated continuously and can be detected by the driver via brake pedal pulsation.
This type is used in simple-rear wheel-only ABS designs. With this setup, the controller monitors each wheel individually to make sure it is achieving maximum braking force. Three-channel, four-sensor ABS There is a speed sensor on all four wheels and a separate valve for each of the front wheels, but only one valve for both of the rear wheels. Older vehicles with four-wheel ABS usually use this type.
Three-channel, three-sensor ABS This scheme, commonly found on pickup trucks with four-wheel ABS, has a speed sensor and a valve for each of the front wheels, with one valve and one sensor for both rear wheels. The speed sensor for the rear wheels is located in the rear axle. This system provides individual control of the front wheels, so they can both achieve maximum braking force. Two-channel, four sensor ABS This system, commonly found on passenger cars from the late '80s through early s uses a speed sensor at each wheel, with one control valve each for the front and rear wheels as a pair.
It has one valve, which controls both rear wheels, and one speed sensor, located in the rear axle. This system operates the same as the rear end of a three-channel system. The rear wheels are monitored together and they both have to start to lock up before the ABS kicks in. Provide better chance of steering. Highly adaptable to every surface. Greatly reduces the possibility of vehicle skidding. Faster reactions to situations because of completely ECU controlled.
Require complete overhaul on damage of few parts. Delicate system, easy to harm and damage. Longer stopping distances due to system errors.
It stops wheel spin by reducing engine power or temporarily applying the brakes to that wheel, allowing the car to accelerate smoothly, even on slippery surfaces. In modern vehicles, traction-control systems utilize the same wheel-speed sensors employed by the anti lock braking system.
These sensors measure differences in rotational speed to determine if the wheels that are receiving power have lost traction.
When the traction-control system determines that one wheel is spinning more quickly than the others, it automatically "pumps" the brake to that wheel to reduce its speed and lessen wheel slip. In most cases, individual wheel braking is enough to control wheel slip. However, some traction-control systems also reduce engine power to the slipping wheels. On a few of these vehicles, drivers may sense pulsations of the gas pedal when the system is reducing engine power much like a brake pedal pulsates when the anti lock braking system is working.
Many people mistakenly believe that traction control will prevent their vehicle from getting stuck in the snow. For a frontal-offset crash, the force and geometry of only the left or right portion of the vehicle front may be applicable. For interaction with reasonably compliant roadside devices such as roadside hardware crush levels rarely exceed millimeters unless localized intrusion by barrier sections occurs.
The use of barrier force data permits a finer discrimination of vehicle stiffness and geometry that can be further investigated as appropriate aggressivity metrics. From this approach, metrics may be derived from barrier test data that may be used to assess vehicle geometric and stiffness aggressiveness in frontal type crashes.
The load cells array consists of 4 rows of 9 cells, as shown in Figure 3.
The rows are designated by letters A through D, with A at the bottom. The columns are numbered 1 through 9, starting at the left, facing the barrier.
The array is subdivided in 6 groupings, 1 through 6, numbered left to right, and beginning with lower left grouping see Figure. In this study, the relationship between barrier forces and their geometric location are of particular interest. In offset crashes, the left or right side of the structure principally deforms and absorbs energy.
In centerline impacts with narrow objects, the center response is primary. In head-on crashes with large overlap, the entire width of the force array may be required. The vertical force distribution of the vehicle structures in contact during the crash is important in assessing the geometric compatibility. To address these various requirements, the barrier measurements have been used to graphically present the forces measured by all load cells.
The force distributions are examined at three points during the crash. The stiffness is calculated by dividing the force measured by the load cells at a particular time by the calculated vehicle crush at that time.
The vehicle crush is determined by double integration of the longitudinal acceleration measured on a structural member close to the vehicle's center of gravity. To quantify the height of the structural loading, a center of impact force was calculated for three columns of cells. The left column contained the 1 and 4 groupings, the center column the 2 and 5 groupings, and the right the 3 and 6 groupings. In addition, the height of the center of force for the total loading was calculated.
For each grouping, the force on each row of cells was assumed to be uniformly 67 distributed. The height of the center of the force was calculated, applying static equilibrium relationships as shown in Figure 3.
The center of force was calculated for vehicle crush of five inches, 10 inches and 15 inches.
In the tables and figures given here all data are reported in metric units. The three crush levels are reported as the approximate metric equivalent - mm, mm and mm. In Figure 3. The force F that is required to resist the sum of the load cell forces from rows A, B, C, and D is determined.
The height of force F is then found by applying moment equilibrium to the barrier forces and moment arms. The height H is defined as the Center of Force. The center of force calculation is made for the entire rows of load cells as well as for the left third, the center third, and the right third of the rows. The force level is less sensitive than the stiffness to the zero time step selection. Consequently, force rather than stiffness is a preferred metric at the selected crush values. This difference in stiffness will result in a higher extent of crush for the Dodge Neon in a frontal crash involving the two vehicles.
This difference illustrates the stiffness differences between the two vehicles. These differences are shown in Figure 3. In a frontal-to-frontal collision, the soft car crushes more than the stiff car at the same interface force.
In the example, the interface force level is kN. The crush of the soft car is mm and the crush of the stiff car is mm. The area under the force-deformation curve is proportional to the energy absorbed. Consequently, the soft car has absorbed about twice as much crash energy as the stiff car.
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This difference illustrates the stiffness incompatibility of the two vehicles. As shown in Figure 3. It should be noted that the difference in the geometric location of the forces generated by the vehicle structures could influence the idealized interaction presented in Figure 3. This difference will be addressed under the discussion of geometric compatibility. The maximum force produced during the crash and the linear stiffness based on the crush at maximum force have been suggested as metrics for stiffness incompatibility.
In view of the force vs. In this study, we propose to investigate the force levels at , , and mm. The forces developed by the vehicle left, center, or right segments of the vehicle front may be applicable in offset collisions. The 50 vehicles are listed in Appendix B of this report. Another 14 vehicles have been analyzed, but the data was found to be of unsuitable quality. In 17 of the cases, data was not reported for three of the four rows of load cells.
The data on the 50 vehicles included in this report should be considered preliminary. Several adjustments in the data will be necessary. For example, some vehicles may not have impacted the center of the barrier.
Shifting of the load cell columns to the right or left will be needed in these cases. In other cases, a single load cell in the array may produce unrealistically high readings.
Finally, adjustments to gain a precise zero time step may be necessary in a few cases.
The vehicle characteristic table shown in Appendix B provides selected results of the barrier data analysis. The nine columns of load cells are divided into three groups as described earlier. The groups are: left, center and right. The percent of the barrier force on the A, B, C, and D rows are designated in the last four columns of the tables.
The values listed in the table are for a vehicle crush of mm. Data Processing Procedures The acceleration data points were the average of two accelerometer readings. The two accelerometers selected were the left and right rear floor pan or the left and right rear seat accelerometers. In the event inaccurate velocity changes of the vehicle were predicted, the best available accelerometers were selected.
It was assumed that the zero time steps provided in the data were accurate, and were identical for the force and acceleration data. Beginning with the zero time step, acceleration data and barrier force data were sampled every 2 ms for ms. The resulting acceleration data and load cell data were the input for subsequent analysis. In examining the resulting data, several inconsistencies were observed. The most frequent was an initial force on load cells at time zero.
A second problem was the presence load on cells outside the contact region, or unrealistically high loads on cells inside the contact region. These cases were not rejected in the event the consequence was negligible. Finally, in some cases, the acceleration readings produced a higher or lower delta-V than expected.
In the event that the delta-V prediction from the accelerometers up to the time of maximum crush was reasonable, the data was not rejected.
Discussion The results of the barrier data provide useful insights into the geometry and height of the stiffest portions of the vehicle structure in a barrier crash. By developing metrics for these properties, it may be possible to quantify more precisely vehicle compatibility with a variety of impacted structures.
Other structures may include any aspects of opposing vehicles or roadside safety systems. The proposed metrics need to be further evaluated. The evaluation should include the assessment of a large number of vehicles and an assignment of proposed compatibility metrics based on barrier crash test data and physical measurements. The resulting metrics should be evaluated by determining the extent to which they explain the aggressiveness characteristics observed in the on-the-road crash data.
The application of load cell barrier data provides valuable measurements for assessing the loading of vehicles in a crash. Metrics such as vehicle mass, geometry bumper height, sill height, and hood profile and structural factors such as body type and stiffness can be used in combination to assess effectiveness of roadside hardware devices during impact.
Ideally, design and performance corridors for 71 vehicles and roadside hardware devices should be aligned to ensure optimal performance of highway systems during crashes. During this testing, two different vehicles of similar size, class and mass impacted a W-beam guardrail under the same conditions yet resulted in drastically different post impact vehicle behavior.
Tables 3.When viewing the car from the front, this measurement is taken from the inside of the left frame rail to the inside of the right frame rail at the point closest to the front of the car possible. Tait, A. The load cells array consists of 4 rows of 9 cells, as shown in Figure 3.
vehicle body engineering
Ata Elyas. The resulting acceleration data and load cell data were the input for subsequent analysis.
To aid the selection of an average vehicle, Appendix B lists over vehicle makes and models and their corresponding design attributes.