RMS (Reliability-Maintainability-Safety-Supportability) engineering is emerging as the newest discipline in product development due to new credible, accurate, quantitative methods. Weibull Analysis is foremost among these new tools. New and advanced Weibull techniques are a significant improvement over the original Weibull approach. This workshop, originally developed by Dr. Bob Abernethy, presents special methods developed for these data problems, such as Weibayes, with actual case studies in addition to the latest techniques in SuperSMITH® Weibull for risk forecasts with renewal and optimal component replacement.
Heavy vehicles such as construction machinery generally require a large traction force. For this reason, axle components are equipped with a final reduction gear to provide a structure that can generate a large traction force. Basic analysis of vertical load, horizontal load (traction force), centrifugal force, and torsional torque applied to the wheels of heavy vehicles such as construction machinery and industrial vehicles, as well as actual working load analysis during actual operations, were conducted and compiled into a load analysis diagram. The loosening tendency of wheel bolts and nuts that fasten the wheel under actual working load was measured, and the loosening analysis method was presented. The causes of wheel fall-off accidents in heavy trucks, which have recently become a problem, were examined. Wheel bolts are generally tightened by the calibrated wrench method using a torque wrench.
Brake judder affects vehicle safety and comfort, making it a key area of research in brake NVH. Transfer path analysis is effective for analyzing and reducing brake judder. However, current studies mainly focus on passenger cars, with limited investigation into commercial vehicles. The complex chassis structures of commercial vehicles involve multiple transfer paths, resulting in extensive data and testing challenges. This hinders the analysis and suppression of brake judder using transfer path analysis. In this study, we propose a simulation-based method to investigate brake judder transfer paths in commercial vehicles. Firstly, road tests were conducted to investigate the brake judder of commercial vehicles. Time-domain analysis, order characteristics analysis, and transfer function analysis between components were performed.
Lithium-ion batteries (LIBs) serve as the main power source for contemporary electric vehicles (EVs). Safeguarding these batteries against damage is paramount, as it can trigger accelerated performance deterioration, potential fire hazards, environmental threats, and more. This study explores the damage progression of a commercial vehicle LIB module containing prismatic cells under crush loading. We employed computational simulations of mechanical loading tests to investigate this behavior. Physical tests involved subjecting modules to low-speed (0.05 m/s) indentations using a V-shaped stainless-steel wedge, under 6 unique loading conditions. During the tests, the force and voltage change with wedge displacement were monitored. Utilizing experimental insights, we constructed a finite element (FE) model, which included the key components of the battery module, such as the prismatic cells, steel frames and various plastic parts.
For the design optimization of the electric bus body frame orienting frontal crash, considering the uncertainties may impact the crashworthiness performance, a robust optimization scheme considering tolerance design is proposed, which maps the given acceptable objective and feasibility variations into the parameter space to analyze the robustness. Two contribution analysis methods those are the entropy weight and TOPSIS method and the grey correlation calculations method are adopted to screen all the design variables, and 15 shape design variables with relatively high effect are chosen for design optimization. A symmetric tolerance and interval model is used to describe the uncertainty of 15 shape design variables of the key components of the bus body skeleton to form an uncertainty optimization problem in the form of an interval, and a triple-objective robust optimization model is developed to optimize the shape design variables and tolerances simultaneously.
In order to improve the braking energy recovery rate of pure electric garbage trucks and ensure the braking effect of garbage trucks, a strategy of optimizing the regenerative braking fuzzy control of garbage trucks by particle swarm optimization is proposed. A multi-stage front and rear wheel braking force distribution curve considering braking effect and braking energy recovery is designed. According to the vehicle demand braking force and braking strength, a hierarchical regenerative braking fuzzy control strategy is established. The first layer is based on the vehicle demand braking force, based on the front and rear axle braking force distribution scheme, and uses the fuzzy controller to realize the first distribution of the front axle braking force.
This paper investigates the tire-terrain interaction for a Mixed Service Drive (MSD) truck tire with two different solid rubber material definitions using a Finite Element Analysis (FEA) virtual environment. An MSD truck tire sized 315/80R22.5 is designed with two different solid rubber material definitions: a legacy Hyperelastic Solid Mooney-Rivlin material definition and an Ogden Visco-Hyperelastic solid material definition. The popular Mooney-Rivlin is a material definition for solid rubber simulation that is not built with element elimination and is not easily applicable for thermal applications. The Ogden Visco-Hyperelastic material definition for rubber simulations allows for element destruction and is more suited for designing tire wear models. Both the Mooney-Rivlin and Ogden-equipped MSD truck tires are subjected to a static vertical stiffness test to validate their static domain characteristics.
An experiment is carried out to measure creep groan of a drum brake located in a trailer axle of a truck. The noise nearby the drum brake and accelerations on brake shoes, axle and trailer frame are collected to analyze the occurring conditions and characteristics of the creep groan. A model with 1/4 trailer chassis structures is established using ADAMS for analyzing brake component vibrations that generates the creep groan. In the model, the contact force between involute cam and rollers of brake shoes, the contact friction and damping characteristics between brake linings and inner circular surface of brake drum, and the properties of chassis structure are included. Dynamic responses of brake shoes, axle and trailer frame during the braking process are estimated using the established model and the responses are compared with the measured results, which validate the model.
Lightweight design is a key factor in general engineering practice; however, it often conflicts with fatigue durability. In this study, a methodology to enhance the efficiency of fatigue optimization is proposed, with a case study on heavy-duty vehicle suspension brackets illustrating the approach. This case study is based on random load data collected from fatigue durability tests in proving grounds, and fatigue failures of the heavy-duty vehicle suspension brackets were observed and recorded during the tests. An integrated approach to multi-objective fatigue optimization was introduced by employing multi-axial time-domain fatigue analysis under random loads combined with the non-dominated sorting genetic algorithm II with archives. While evaluating fatigue life within optimization loops, particularly for multi-axial random load fatigue in the time domain, is time-intensive, this study introduces modifications to improve computational efficiency.
Catalytic converters have been considered as an integral part of the vehicle powertrain for over a decade now, their application along with the engines increased significantly with the constant evolution of emission standards. Recent regulations keep a strict control on the major four pollutants of engine exhaust gas, i.e., Carbon Monoxide (CO), Nitrogen Oxides (NOx), Hydrocarbons (HC) & Particulate Matter (PM), which demands a highly efficient aftertreatment system. Efforts are continuously being made to downsize the engine for better fuel economy and low emissions, this puts additional requirement of designing a compact aftertreatment system equipped with Diesel Oxidation Catalyst (DOC), Diesel Particulate Filter (DPF) and Selective Catalytic Reduction (SCR). Compact catalytic converters experience larger vibration force transferred from the engine and hence the durability of the product is significantly impacted.
The current battery carrier for commercial vehicles is made of steel and is designed to hold two batteries weighing approximately 80 kg to 100 kg. However, this battery carrier faces several issues including corrosion, chemical reactivity, high maintenance requirements and its heavy weight. To tackle these challenges, a fiber-reinforced composite battery carrier is designed and developed specifically for commercial vehicles. The objective is to identify a solution that can meet the performance requirements of both static and dynamic loading, thereby reducing the overall weight. The proposed composite battery carrier offers a lightweight design, requires minimal maintenance, possesses high tensile strength and stiffness and is corrosion and chemical resistant. Furthermore, it provides the flexibility to integrate battery cover locking arrangements for added convenience and security.
As the automotive industry focuses on fuel-efficient and eco-friendly vehicles along with reducing the carbon footprint, weight reduction becomes essential. Composite materials offer several advantages over metals, including lighter weight, corrosion resistance, low maintenance, longer lifespan, and the ability to customize their strength and stiffness according to specific loading requirements. This paper describes the design and development of the Rear Under Run Protection Device (RUPD) using composite materials. RUPD is designed to prevent rear under-running of passenger vehicles by heavy-duty trucks in the event of a crash. The structural strength and integrity of RUPD assembly are evaluated by applying loads and constraints in accordance with IS 14812:2005. The design objective was to reduce weight while maintaining a balance between strength, stiffness, weight, manufacturability, and cost.
Leaf Springs are commonly used as a suspension in heavy commercial vehicle for higher load carrying capacity. The leaf springs connects the vehicle body with road profile through axle & tire assembly. It provides the relative motion between the vehicle body and road profile for improving the ride & handling performance. The leaf springs are designed to provide the linear stiffness and uniform strength characteristics throughout its travel. Leaf springs are generally subjected to dynamic loads which are induced due to different loads & driving patterns. Leaf spring design should be robust as any failure in leaf springs will put vehicle safety at risk and cost the vehicle manufacturer reputation. The design of a leaf spring based on the conventional methods predicts the higher stress levels at the leaf spring center clamp location and stress levels gradually reduce from the center to free ends of the leaf spring.
A major concern for a high-power density, heavy-duty engine is the durability of its components, which are subjected to high thermal loads from combustion. The thermal loads from combustion are unsteady and exhibit strong spatial gradients. Experimental techniques to characterize these thermal loads at high load conditions on a moving component such as the piston are challenging and expensive due to mechanical limitations. High performance computing has improved the capability of numerical techniques to predict these thermal loads with considerable accuracy. High-fidelity simulation techniques such as three-dimensional computational fluid dynamics and finite element thermal analysis were coupled offline and iterated by exchanging boundary conditions to predict the crank angle-resolved convective heat flux and surface temperature distribution on the piston of a heavy-duty diesel engine.
Nowadays, Bismuth (Bi) is being applied as an overlay material for engine bearings instead of Lead (Pb) which is an environmentally harmful material. Bi overlay has already been a solid performer in some automotive engine sectors due to its superior load carrying capacity and good robustness characteristic which are necessary to maintain its longevity during the lifetime of engines. The replacement is also seen on relatively larger size engines, such as Trucks and Off-highway heavy duty applications. Basically, these applications require higher power output than passenger cars, and the expected component lifecycle becomes longer. Even Bi has similar material characteristic with traditional Pb, it becomes challenging for the material alone to satisfy these requirements. Polymer overlay is known for its superior anti-wear performance and longer lifetime due to less adhesion against a steel counterpart than metal materials (included Bi).
In the last decades the locomotion of wheeled and tracked vehicles on soft soils has been widely investigated due to the large interest in planetary, agricultural, and military applications. The development of a soil contact model which accurately represents the micro and macro-scale interactions plays a crucial role for the performance assessment in off-road conditions since vehicle traction and handling are strongly influenced by the soil characteristics. In this framework, the analysis of realistic operative conditions turns out to be a challenging research target. In this research work, a semi-empirical model describing the interaction between a tyre and homogeneous and fine-grained soils is developed in Matlab/Simulink. The stress distribution and the resulting forces at the contact are based on well-known terramechanics theories, such as pressure-sinkage Bekker’s approach and Mohr-Coulomb’s failure criterion.