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Abstract During mining material hauling, the chassis frame structure of rear dump trucks is subjected to fatigue loading due to uneven road conditions. This loading often leads to crack propagation in the frame rails, necessitating the determination of stresses in the critical zone during the design stage to ensure structural integrity. In this study, a computer-aided engineering (CAE) methodology is employed to size and select the rectangular profile cross section of the chassis frame rail. A detailed design investigation of the chassis frame is conducted to assess its load resistance, structural flexibility, and weld joint fatigue life under critical stresses arising from combined bending and torsion loads. The optimization process aims to determine the optimal rail size and material thickness, striking a balance between minimizing mass and maximizing structural reliability.

Abstract With the use of the stepped surface of the friction pairs of the stepped bearings (SB) in the high-speed centrifugal pumps, its liquid film thickness is suddenly changed and it was discontinuously distributed in the direction of motion of pump. To ensure the continuity of the liquid film thickness and enhance the lubrication efficiency of the pump, based on the lubrication model of the SB, two other structures of the inclined surfaces [inclined bearings (IB)] and curved surfaces [curved bearings (CB)] used to replace stepped surfaces of the SB are investigated, respectively. Under the same conditions of the minimum thickness of the liquid film and initial dimensions of the sliding friction pairs, the influence of both the thickness ratio (α) of the liquid film and dimension ratio (β) in the direction of motion of SB, IB, and CB on the bearing capacity and friction coefficient of the liquid film are simulated and analyzed, respectively.

Abstract In view of the combustion efficiency and emission performance, various new clean combustion modes put forward higher requirements for the performance of the fuel injection system, and the cavitating two-phase flow characteristics in the injector nozzle have a significant impact on the spray atomization and combustion performance. This article comprehensively discusses and summarizes the factors that affect cavitation and the effectiveness of cavitation, and presents the research status and existent problems under each factor. Among them, viscosity factors are a hot research topic that researchers are passionate about, and physical properties factors still have the value of further in-depth research. However, the importance of material surface factors ranks last since the nozzle material was determined. Establishing a more comprehensive cavitation–atomization model considering various factors is the focus of research on cavitation phenomena.

Abstract All two-wheeler industries validate their product’s fatigue life on proving track before heading for mass production. Proving test tracks are made to simulate the end-user environment in order to find out the possible fatigue failures during each development stage of vehicle design, which in turn helps the CAE analysts to verify the design before it goes to the end-user hands. In this article we present the design and failure analysis of sub-frame assembly of motorbike observed during the accelerated fatigue test on proving track. Sub-frame main rod was found broken exactly between two weld endings during fatigue test before reaching 6% of the target fatigue life. Possible causes of sub-frame failures have been identified/analyzed in detail using fish bone diagram. A finite element analysis (FEA) model of sub-frame assembly was developed and a random response analysis was carried out on initial design.

Abstract Pre-chamber jet ignition technologies have been garnering significant interest in the internal combustion engine field, given their potential to deliver shorter burn durations, increased combustion stability, and improved dilution tolerance. However, a clear understanding of the relationship between pre-chamber geometry, operating condition, jet formation, and engine performance in light-duty gasoline injection engines remains under-explored. Moreover, research specifically focusing on high dilution levels and passive pre-chambers with optical accessibility is notably scarce. This study serves to bridge these knowledge gaps by examining the influence of passive pre-chamber nozzle diameter and dilution level on jet formation and engine performance.

Abstract Vehicle vibration is the key consideration in the early stage of vehicle development. The most dynamic system in a vehicle is the powertrain system, which is a source of various frequency vibration inputs to the vehicle. Mostly for powertrain mounting system design, only the uncoupled powertrain system is considered. However, in real situations, other subsystems are also attached to the powertrain unit. Thereby, assuming only the powertrain unit ignores the dynamic interactions among the powertrain and other systems. To address this shortcoming, a coupled powertrain and driveline mounting system problem is formulated and examined. This 16 DOF problem is constructed around a case of a front engine-based powertrain unit attached to the driveline system, which as an assembly resting on other systems such as chassis, suspensions, axles, and tires.

Abstract With higher customer expectations and advances in vehicular technology, automotive functions and operations are becoming more intelligent. Electric self-priming door locks fulfil the automatic closing and locking of side doors, hatchback doors, sliding doors, liftgates, decklids, etc. They are widely implemented into high-end models for the elegance of soft closing. In the list of perceived vehicle qualities, door-closing sound quality has been one of the important customer concerns in the market. In comparison to conventional door locks, electric self-priming door locks add another dimension to the development of sound quality for noise, vibration, and harshness (NVH) efforts. In this article, the characteristics of door-closing sound involving self-priming door lock mechanisms are analyzed and illustrated. Human perception of different sounds from the self-priming door lock working process is ranked by subjective evaluations.

Abstract This article describes the research work taken to compare the effect of air blast and surface-buried mine blast loading on an armored fighting vehicle (AFV) escape hatch, using the coupled Eulerian-Lagrangian (CEL) technique. Two types of escape hatch were considered for the study, namely, the flat plate version and double-side curved-plate version. To evaluate the research methodology used in this investigation, initially, a published experimental work on a circular plate subjected to air blast was chosen and a benchmark simulation was carried out using the CEL technique to establish the simulation procedure. Then the established procedure was utilized for further analysis. It was observed that the variation in the deformation between the published literature and the simulation work was well within the acceptable engineering limits.

Abstract Optimization is essential in real-life mechanical engineering problems that mostly are nonlinear, depend on mixed decision variables, and are usually subject to constraints. However, most of the studied problems are modelled assuming continuous variables. A limited number of studies have been devoted to cases with mixed variables. Moreover, there is a lack of algorithm treating mixed variable problems properly. This article introduces a hybrid algorithm that can handle constrained problems depending on continuous or mixed variables. The proposed algorithm combines two meta-heuristics, Jaya and particle swarm optimization (PSO). PSO is one of the most popular methods to solve nonlinear problems, and Jaya is a novel parameter-free optimization algorithm. This new hybrid optimization algorithm is proposed in order to improve the convergence speed and to investigate what improvements it will bring to optimization problem solutions.

Abstract Under the influence of the interactions between the vibratory drum/wheel and deformable terrains, the ride comfort of the soil compactors is greatly affected. Therefore, the isolation systems of the cab and driver’s seat of the soil compactors have been researched and developed to improve ride comfort. Based on the existing research results, this study provides an overview of the development of the isolation systems of the cab and driver’s seat of the soil compactors. The research result shows that the cab isolations used by the semi-active hydraulic mounts (SHM) or semi-active hydraulic-pneumatic mounts (SHPM) can greatly improve the driver’s ride comfort and control the cab shaking, whereas the driver’s seat suspension embedded by the negative stiffness structure (NSS) strongly improves the driver’s ride comfort.

Abstract The use of converging-diverging (C-D) variable area nozzle (VAN) in military aeroengines is now common, as it can give optimal expansion and control over engine back pressure, for a wide range of engine operations. At higher main combustion temperatures (desired for supercruise), an increase in the nozzle expansion ratio is needed for optimum performance. But changes in the nozzle throat and exit areas affect the visibility of engine hot parts as the diverging section of the nozzle is visible for a full range of view angle from the rear aspect. The solid angle subtended by engine hot parts varies with change in visibility, which affects the aircraft infrared (IR) signature from the rear aspect. This study compares the performances of fixed and variable area nozzles (FAN and VAN) in terms of engine thrust and IR signature of the engine exhaust system in the boresight for the same increase in combustion temperature.

Abstract Gasoline compression ignition (GCI) is a promising combustion technology that can help the commercial transportation sector achieve operational flexibility and meet upcoming criteria pollutant regulations. However, high-pressure fuel injection systems (>1000 bar) are needed to enable GCI and fully realize its benefits compared to conventional diesel combustion. This work is a continuation of previous durability studies that identified three key technical risks after running gasoline-like fuel through a heavy-duty, common rail injection system: (i) cavitation damage to the inlet check valve of the high-pressure pump, (ii) loss of injector fueling capacity, (iii) cavitation erosion of the injector nozzle holes. Upgraded hardware solutions were tested on a consistent 400- to 800-hour NATO durability cycle with the same gasoline-like fuel as previous studies. The upgraded pump showed no signs of abnormal wear or cavitation damage to the inlet check valve.

Abstract A set of multidisciplinary topology optimization (MTO) and fast validation method is discussed, which can be applied in the car body concept design stage. First, considering seven typical loading cases, optimized load path is obtained by MTO. Then an equivalent car body model is built up with new load path. In order to verify its linear and nonlinear performances quickly, original and optimized path models are established, respectively, by using macro elements. The results show that rigidity and collision performance of the optimized path are better than that of the original one. In the meantime, reduce the validation time from hours to minutes.

Abstract The objective of this work is to analyze the signal of a piezoelectric washer installed under the spark plug and to compare the combustion metrics evaluated with such signal to the indexes from a standard piezoelectric sensor for the in-cylinder pressure measurement, considered as the reference. In the first part of the article, the spectrum analysis of the piezoelectric washer pressure trace is proposed. It is demonstrated how such a signal can be used to measure the main combustion and knock indexes. Nevertheless, due to the intrinsic characteristics of the system, the knock index evaluated from the raw pressure trace cannot be directly used to estimate the instantaneous knock intensity. For this reason, a model-based algorithm for Real-Time (RT) application is developed to calculate a corrective factor of the high-frequency content of the signal.

Abstract This article investigates the lateral dynamic behavior of a two-wheel axle bogie frame of an Indian railway vehicle. The influence of the different parameters of the vehicle on stability is investigated. The model is formulated by assigning 10 degrees of freedom (DoF) to the system with yaw and lateral DoF assigned to the bogie frame and vertical, lateral, roll, and yaw DoF assigned to each wheel axle. Linear creep force and moments suggested by Kalker’s linear theory of creep have been accounted for in the analysis. The stability analysis is carried out by transforming the second-order differential equations into first-order differential equations using state-space representation. The present model is validated by comparing the eigenvalues of the analytical model with the same obtained from the finite element (FE) model. The results obtained from the analytical and FE model are in good agreement.

Abstract Fretting is a surface damage phenomenon and is typically observed at the contact interfaces such as bolted, gasketed joints, and the like. It occurs due to the combined effect of normal and tangential loads, which produces a small-amplitude relative sliding between two components that are held together using clamping forces. Fretting-related failures are also observed in multiple components of an internal combustion engine. This article presents the fretting fatigue damage evaluation of a single layer head gasket using a relative new approach, i.e., deviatoric strain amplitude-based method, further combined with the Ding’s empirical parameter D fret2. Corresponding fretting damage results are compared with the traditional approach based on the Ruiz’s parameter F1.

Abstract The gear whine in the electric drive system of an electric vehicle is important and remains a challenge in developing novel electric vehicles. A gearbox dynamic model is established, and the effects of modification parameters on the sound pressure level, transmission error, and contact stress of the gear pair are introduced to reduce the gear whine. A multi-objective optimization study of four modification variables under multiple torque conditions is carried out by using transmission error and maximum contact stress as the objective functions. The eclectic programming method is imported to solve the convergence problem of multi-objective optimization. The influence of modification variables on objective functions is studied by establishing an approximate model of the optimal Latin hypercube design.

Abstract In real-life mechanisms, the design parameters differ from their theoretical values. This difference is due to the manufacturing tolerances of link dimensions and revolute joints of mechanisms. In this article, the effect of link dimensions manufacturing tolerances and joints clearance on the kinematic and dynamic performances of a planar mechanism is studied. A slider-crank mechanism with two joint clearances is considered as a case study. Furthermore, an analytical method based on the partial derivatives is used to determine the mathematical equation representing the kinematic errors of the mechanism. This error depends on the manufacturing tolerances of link dimensions and revolute joints of the mechanisms. The Lagrangian equation is adopted to define the mathematical expression of the mechanism motion. Two objectives are considered regarding the acceleration error and the dynamic performance.

Abstract Due to their high strength and good flexibility, wire ropes are widely used in various intense applications. A wire rope will present complex wave mechanics, especially under impact conditions. In this article, wire ropes (steel core rope and hemp core rope alternately twisted) were used to study the wave dynamic response of steel wire ropes with preload shock. The transmission law of wire rope shock waves was obtained through actual measurements. The results showed that the compression wave and shear wave were generated and propagated along the rope after impact. The conduction of shear waves had significant reflection characteristics, and the reflected waves overlapped with each other. The conduction velocity of the impact shear wave of the steel core wire rope increased with increasing pretension. The peak tension caused by impact decayed exponentially.

Abstract The dimensional quality of the car body is built on quality management of form, fitment, and functional requirements. Each of these attributes reflects the final product quality and, therefore, needs to be ascertained quantitatively. Design intent and functionality conformance with specifications are paramount to performance, and thus quality. It is accomplished through optimal Geometric Dimensioning and Tolerancing of parts (GD&T), datum/Primary Locating Points (PLP) strategy, tricks/levers, and assembly design. Challenges stem from the complexity involved in the datum layout strategy and its optimization for desired deviations. Incorrect datum schemes in design prompt underconstrained fixtures, redundant datum, the sensitivity of datum layout, etc. and induce defects in later stages. The end effect is smoothing out the variation issues leading to compromise in quality.