###### Abstract  
In the automotive sector, the use of multi-body software for modeling of existing vehicles has become essential due to its advantages in understanding vehicle dynamics in different situations and improving vehicle performances. This paper aims to model an off-road truck (4 \(\times\) 4) by using ADAMS software 2020. Several steps must be achieved, including experimentally identifying some truck characteristics such as the mass, center of gravity coordinates, and tire vertical stiffness. The truck features leaf springs in both the front and rear suspensions, which must be validated before their integration into the full model due to their modeling complexity. This validation is performed by comparing the force-displacement characteristics obtained experimentally with simulation results from ADAMS, showing a good agreement. Then, the full truck is modeled in ADAMS software and validated through an experimental test using a repeated double-lane change scenario with two tests for the validation of the truck's lateral dynamics. The comparison between the results shows a good correlation, validating the multi-body truck model. truck model; leaf spring; simulation; vehicle dynamic; model validation +
Footnote †: journal: Medical Physics  
0000-0001-8000-0001-8000]C. Benmeddah  
0000-0002-3300-0000]V. [PERSON]  
0000-0002-3300-0002-3300-0002-33000]V. Benmeddah  
0000-0002-3300-0002-3300-0002-3300-0002-3300-0002-33000-002-33000-002-33000-002-33000-002-33000-002-33000-002-33000-002-33000-002-33000-002-33000-002-333000-002-33000-002-33 absorber spring and anti-roll bar, along with their corresponding characteristics, and the links (joints and attachments) used for the connections between the elements. Finally, validation of the developed model is necessary through experimental tests to verify its applicability and accuracy. The study of vehicle lateral dynamics is crucial in understanding their behavior in different driving situations. The simplest model is a bicycle model [9], which employs mathematical equations to approximate the vehicle's motion and identify key parameters essential for understanding its stability. However, this model simplifies the vehicle as a single track with two wheels and does not account for roll motion, suspension dynamics, and detailed tire behavior [10], all of which are crucial for accurate stability analysis. In contrast, multi-body models offer advantages by integrating these factors into comprehensive mathematical equations that describe the full vehicle dynamics. Driving stability is a multifaceted concept that involves the interplay of several vehicle dynamics factors, including steering, suspension, and braking systems. The major components of vehicles that play a crucial role in ensuring the best vehicle performance, such as passenger comfort, driving stability, and maneuverability, are suspension systems as well as powertrain suspension systems (because the powertrain of a vehicle accounts for 10-15% of the total mass) [11]. A good suspension system absorbs shocks from road irregularities, preventing excessive body roll and maintaining vehicle posture. The system must balance comfort and performance, adapting to various road conditions to provide a stable and smooth ride without sacrificing maneuverability [12]. By carefully designing and adjusting the characteristics of individual elements of these systems, conflicting goals can be achieved, including ride comfort, maneuverability, and stability. Suspension systems have several classifications depending on the criterion used. Hence, they can be classified according to their configuration as dependent or independent, according to their function as passive and active, and according to the type of spring used which can be a coil spring, a leaf spring [13; 14; 15; 16], etc. The leaf spring is one of the types used in suspension systems to support light, medium, and heavy loads. It has demonstrated its effectiveness in maintaining the best vehicle performance under various conditions.