In modern society of industrialization, there are more and more trucks running on the roads transporting raw material or finished goods. With the rise of traffic accidents between cars and trucks, we need to put more attention to the tail of the truck.
The authors design a device which can be fixed on the rear beams of the truck chassis. It’s called anti-collision equipment to avoid the cars crash into the truck tail. Although there are many available anti-collision solutions on trucks, studies show that there are still areas for improvement.
The truck we choose to study is the heavy-duty truck of Jiefang J6M which is one of the mainstream models in China. The rear space of the truck is about 2400 mm (Width) × 2000 mm (Length) × 1050 mm (Height) and we design the device according to that size.
In other to achieve a better design, the authors study the literature and theses about energy absorption board, non- Newtonian fluid damper and thread shearing absorber. All of these three shock absorbers were combined together to make the design useful for different impact intensity. The height of the anti-collision is made adjustable for on-road and on-working site use. The authors design all the devices with Autodesk Inventor and validate material and dimensions by FEM Abaqus simulation. MATLAB simulation is used for calculating of fluid damper shock absorption. To make the best choice, the authors consider economic and reusability factors too.
SURVEY OF RELATED WORK
This device shown in the figure above uses a simple and settled steel structure in order to avoid truck tail collision. Features and advantages: settled triangle structure, popular used, easy to be installed and cost low. Disadvantages: sudden stop increase the damage to human’s body and also after collision damage of the vehicle is irreparable.
- Corrugated Plate
- Cross Rod
- the Block
- Connecting Rod
- Shear Sliding Blocks
- Absorbing Thread
- Positioning Device
This idea illustrated in Figure 8 uses slider-crank mechanism and thread shear energy absorption in order to design a new device of truck tail collision avoidance.
PROBLEM STATEMENT, OBJECTIVES AND MAIN CONTRIBUTION
The purpose of this thesis is to design a anti-collision equipment which can be fixed on the rear beam of the truck chassis in order to avoid cars crash into the tail of the truck.
During the design process, the main problem arises as we intend to make the anti-collision device to absorb the energy piecewise. When the crash is at low speed, the energy absorption board and non-Newtonian fluid damper will absorb energy (the device is not damaged) so that user does not need to change the device and that will save your money, but when the accident impact is really high, the limit block will be cut and three parts will work together to save car driver’s life. The limit block is designed in a way that it remains intact before a certain magnitude of impact force.
IDEA, CONCEPT AND SOLUTION
The main working parts of the device are divided into three parts: energy absorption board, non-Newtonian fluid damper and thread shearing absorber. They are all energy absorbing parts.
- Energy absorption board
- Non- Newtonian fluid damper
- Thread shearing absorber
We use two steel boards with a big rubber substitute the energy absorption board. So now if a car crashed on it at low speed, the rubber will absorb the energy and the piston will move into the cylinder to absorb the energy, too. But after that we don’t need to change the device because the components are not damaged.
The result shows that stress suffered much smaller than allowable stress so the structure will not bend or break during crash. The impact energy can be absorbed as design. The safety number is around 8 to 15. It turns out our design will work as what we design.
CONCLUSION AND FUTURE WORK
We’ve done all the calculation, modelling and simulation. It turns out our device will work as it was intended during the start of this thesis. Detailed calculation and drawing will help to manufacture this device. Simulation result has shown the validity of the model.
The non-Newtonian behaviour has been described as second order function; studies are required to find a fluid with similar properties. A full dynamic simulation in comsol multi-physics software will be interesting for further validation of the proposed design’s effectiveness.
Rugged mountain road and the construction site have higher requirements about the height of vehicle chassis. The device is adjustable in our design, but it has to be adjusted by hands. So in future work, there is an idea about it. We add an electric system to run the tight en rope device. It is more convenient for adjusting the dampers in different environment.
Source: Blekinge Institute of Technology
Authors: Huan Han | Lujun Gu | Shaojie Lou