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Truck chassis is to provide structural integrity and stability to the commercial vehicle. In addition to
supporting various components like, transmission system, body frames and payload to be placed upon it.
Normally High strength low carbon steel is used as a main chassis material of heavy-duty trucks in our
country

.In this project, Aluminium lithium alloy is used as the alternative chassis material for heavy duty truck. In
this Aluminium lithium alloy, 1% percentage of Lithium added to Aluminium reduces the density of
material by 3% and increase in elastic modulus up to 7%. For a chassis frame thickness of 6 mm the
Aluminium lithium alloy has the ability to give high strength with low density over high strength low
carbon steel alloy.

1. “VIBRATION ANALYSIS OF HEAVY-DUTY TRUCK CHASSIS FRAMES FOR ENHANCED PERFORMANCE AND DURABILITY” Submitted to JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY, ANANTAPUR MASTER OF TECHNOLOGY In MACHINE DESIGN DEPARTMENT OF MECHANICAL ENGINEERING By C MOHAN 19F41D1501 Under the Esteemed Guidance of Mr. N NAGESH, M.Tech., (Ph.D.) Associate Professor

2. ABSTRACT Truck chassis is to provide structural integrity and stability to the commercial vehicle. In addition to supporting various components like, transmission system, body frames and payload to be placed upon it. Normally High strength low carbon steel is used as a main chassis material of heavy-duty trucks in our country .In this project, Aluminium lithium alloy is used as the alternative chassis material for heavy duty truck. In this Aluminium lithium alloy, 1% percentage of Lithium added to Aluminium reduces the density of material by 3% and increase in elastic modulus up to 7%. For a chassis frame thickness of 6 mm the Aluminium lithium alloy has the ability to give high strength with low density over high strength low carbon steel alloy . By using this aluminium lithium alloy we can be able to reduce one third of gross weight of vehicle chassis frame while compared to present chassis frame material. The modelling of the heavy duty truck chassis (Ashok Leyland ) done by using Pro-E and The comparison of stress distribution and dynamic behaviour like natural frequency of truck chassis made of high strength low carbon steel alloy and aluminium lithium alloy is done by using ANSYS software.

3. INTRODUCTION A Chassis forms the main skeleton of any vehicle to which the engine body, wheels, axle assemblies etc. are attached. The different categories- luxury car, multi-utility vehicle, heavy vehicle etc. that a vehicle falls under determine the shape and structure of the chassis. The frame is the backbone or structural centre of the vehicle. Proper alignment is of great importance to maintain the proper relationship between the body, power train, steering geometry and corresponding unit. Improper frame alignment is usually the result of an accident, or the vehicle being operated with excessive loads, not properly positioned. The chassis has all the essential components, required to the vehicle, steer the vehicle and stop the vehicle. The chassis is a portion of the vehicle that carries the engine transmission unit, steering system and suspension system etc. The material used to make car and truck frame should have the following properties.

4. PROBLEM IDENTIFICATION Normally High strength low carbon steel is used as a main chassis material of heavy-duty trucks in our country in which the overall weight of the chassis is increased by 7% for reducing the deflection under load condition, road shocks to increase the stiffness of chassis. Due to this the gross weight of the vehicle is also increased.

5. METHODOLOGY The model is built using Pro/ENGINEER modelling software for chassis to required dimensions. The model is imported to ANSYS for harmonic analysis MESH the model by using free mesh method. Change the analysis type to harmonic from static conditions. Giving the minimum and maximum frequency values under the subsets of 100. Load conditions are given to chassis model and solve the problem. The model is tested for amplitude between Al-Li Alloy and HSLC steel. Comparative study on performance and weight of the chassis of Al-Li Alloy and HSLC steel is to be done

6. EXPERIMENT ANALYSIS OF CHASSIS Model o f Chassis Frame : Pro/Engineer is a computer graphics system that enables the creation of diverse mechanical designs and facilitates associated design and manufacturing processes. In simpler terms, Pro/Engineer serves as a powerful tool for visually designing and conceptualizing mechanical components, while also providing the necessary capabilities for seamless integration with manufacturing workflows. The system employs a 3D solid modeling system as its foundation and employs the feature-based parametric modeling approach as its fundamental methodology. Another alternative name for this could be "Integrated 3D Modeling System with Feature-Based Parametrics." In short, Pro/ENGINEER is a feature-based, parametric solid and surface modeling system with many extended design and manufacturing applications.

7. Importing the model to the ANSYS apdl File->Import->IGES->(window)leave the default settings and select OK->(window ) browse to find the iges part where you saved it (the part is called “lab_part.igs”) and open it into ANSYS. Note you can use the mouse buttons to dynamically orient the model if you pick the upper right view menu button (hold cursor over button and it should say “Dynamic Model Mode”). Also, use Plot and PlotCntrls to display the key points, lines, and volumes that are automatically brought in with the iges model.

8. Material Properties Mesh Generation: Every analysis requires some material property input: Young’s modulus (EX), Poisson’s ratio (PRXY) for structural elements, thermal conductivity (KXX) for thermal elements, etc. To define the material properties: Main Menu>Preprocessor>Material Props>Material Models Then, the structure is broken (or meshed) into small elements. This involves defining the types of elements into which the structure will be broken, as well as specifying how the structure will be subdivided into elements (how it will be meshed). This subdivision into elements can either be input by the user or, with some finite element programs (or add-ons) can be chosen automatically by the computer based on the geometry of the structure (this is called auto meshing) Main Menu>Preprocessor>Meshing>Size Cntrls>Smart Size>Adv Opts

9.   Young’s Modulus 310*10**6 Mpa   Poisson's Ratio 0.3 Density   7860 kg/m³ Type of Chassis material Al-Li 2090 alloy   Young's Modulus 483*10**6 Mpa   Poisson's Ratio 0.3 Density   2590 kg/m³ Properties of HSLC material Properties of Aluminium lithium alloy

10. Applying The Load Condition Forces apply along with the x, y, and z direction. Structural analysis. Displacement : All DOF Pressure / Force : 23,26,30Ton Analysis Type : Harmonic analysis Frequency : 0.01 – 5Hz Frequency Sub steps : 100

11. THEORETICAL CALCULATION OF CHASSIS FOR 23 TON LOAD CONDITION Natural frequency of 2090 Aluminum Lithium alloy for 6mm frame:  Load: 23 Ton  Length of the channel = 9.12 m Thickness of the channel = 0.006m Height of the channel = 0.235 m Moment of inertia, I = 1.41511 * 10**-5 Deflection, ∂ = WL³ / 3EI = 10.58 mm Stiffness, S = F / ∂ = 14.71 N/ m Density, ρ = M / V Mass, M= 58Kg , Total mass of chassis = 170 Kg (chassis frame + 9 nos cross bar Natural frequency, ƒn = 0.12 Hz

12. THEORETICAL CALCULATION OF CHASSIS FOR 26 TON LOAD CONDITION Natural frequency of 2090 Aluminium Lithium alloy for 6mm frame: Load: 26 Ton  Length of the channel = 9.12 m Thickness of the channel = 0.006 m Height of the channel = 0.235 m Moment of inertia, I = 1.41511 * 10**-5 Deflection, ∂ = WL³ / 3EI = 13.45 mm Stiffness, S = F / ∂ = 21 N/ m Density, ρ = M / V Mass, M = 58 Kg Total mass of chassis = 170 Kg (chassis frame + 9 nos cross bar Natural frequency, ƒn =0.30 Hz

13. THEORETICAL CALCULATION OF CHASSIS FOR 30 TON LOAD CONDITION Natural frequency of 2090 Aluminium Lithium alloy for 6mm frame:  Load: 30 Ton  Length of the channel = 9.12 m T hickness of the channel = 0.006 m Height of the channel = 0.235 m Moment of inertia, I = 1.41511 * 10**-5 Deflection, ∂ = WL³ / 3EI = 18.25 mm Stiffness, S = F / ∂ = 21 N/ m Density, ρ = M / V Mass, M = 58Kg Total mass of chassis = 170 Kg (chassis frame + 9 nos cross bar) Natural frequency, ƒn = 3.254 Hz

14. RESULTS AND DISCUSSIONS Loads in ton         Chassis made of HSLC steel Chassis made of 2090 Aluminium Lithium Alloy(5mm) Chassis made of 2090 Aluminium Lithium Alloy (6mm) Stiffness in N/m Natural Frequency in Hz F n in Hz (Theoretical) Stiffness in N/m Natural Frequency in Hz F n in Hz (Theoretical) Stiffness in N/m Natural Frequency in Hz F n in Hz 23tons 14 0.1-1000 0.52 18 0.1 - 1000 0.22 21 0.1 - 1000 0.12 26 tons 0.02-1000 1.12 0.02- 1000 0.34 0.02- 1000 0.30 30 tons 1 *10 4 - 1 *10 8 5.23 1 *10 4 - 1 *10 7 4.23 1 *10 4 - 1 *10 7 3.254 Weight in kg 450 144 170 Comparison of HSLC and AL-LI alloy chassis material

15. CONCLUSION The new material shows minimum amplitude variations while changing the dimensions under same loading condition. Also the weight of the chassis gets reduced. Shape optimization of the chassis is done to Chassis weight optimization. Same material is maintained and the quantity of the material is added. Excess material in the area where is minimum stress acts is reduced. The properties of the material are not changed by shape optimization. Thus, the resonance condition is avoided by keeping the excited frequency less than the natural frequency by changing the chassis frame thickness. The Al-Li chassis frame exhibits a significant weight reduction, being merely one- third of the weight of the HSLC steel counterpart.