Car Body Research Articles

Weight Optimization of the Electric Bus Carbody Structure

Car body is a lightweight construction unit in the form of welded steel construction, has high strength and rigidity against dynamic loading without a fixed change in shape. In this study, the design of the car body bus frame consisted of roof, mascara, side wall, end wall, front part, and underframe. All of these components are designed using Autodesk Inventor Professional 2020 software. The frame material used is SS201. For data retrieval purposes, weight calculations are used in Autodesk Inventor. In the study, we succeeded in making the car body design according to regulations, measuring the weight of the car body, and optimizing the car body. The results showed that with a little optimization on the side wall frame, the weight of the car body bus can be reduced by 11.7% from the initial weight of 461.5 kg to 407.4 kg without changing its characteristics.

Optimizing Sustainability in High-Speed Rail Rolling Stock through CFRP Material Substitution

This research investigates the environmental and operational advantages of replacing traditional materials in high-speed rail (HSR) rolling stock components with advanced composite materials. By substituting key parts—such as the roof, door, car body, brake control unit, braking rheostat, and bogie transom—with glass-filled epoxy, polyester, and nylon, the study achieves a significant reduction in rolling stock weight by 24.61%. This weight reduction contributes to lower energy consumption and reduced CO2 emissions. Additionally, the recyclability and recoverability rates of these composite materials show marked improvements, reaching 73.9% and 78.9%, respectively, compared to 61.4% and 73.1% in the conventional model. The findings demonstrate that integrating composite materials can enhance the sustainability and efficiency of HSR systems by minimizing landfill waste and operational emissions. This study provides a foundational approach to using lightweight, recyclable materials in rail transportation, with promising implications for future sustainable developments in the industry.

An Analysis on Sustainable Automotive Car Body Material Using Weighted Sum method

Introduction: In order to reduce its influence on the environment, the automobile industry must overcome a significant obstacle and switch to sustainability car body materials. This overview examines the demand for cutting-edge materials that enhance vehicle performance, increase recycling, and minimize carbon emissions. The sector can meet expanding transportation demands while promoting a greener future by using sustainable options. The automotive industry plays a major role in the global carbon footprint, with car body products being a major contributor. As sustainability becomes a major concern, the need for eco-friendly alternatives to traditional materials is clear. This introduction explores the concept of sustainable automotive car body materials, highlighting their importance in reducing emissions, conserving resources and promoting a greener future. By exploring innovative solutions, the industry can embrace sustainability while maintaining high-performance standards. Research significance: Research on sustainable automotive car body materials is significant in addressing the pressing challenges facing the automotive industry. By focusing on the development and use of environmentally friendly alternatives, this research aims to reduce the environmental impact of the industry. By reducing carbon emissions and promoting resource conservation, sustainable car body materials can contribute to a greener and more sustainable future. Furthermore, this research has the potential to improve energy efficiency and vehicle performance, leading to safer and more efficient vehicles. Additionally, by meeting growing consumer demand for sustainable options, this research will help automakers gain a competitive edge in the market and align their products with the values and expectations of environmentally conscious consumers. Method: The weighted sum method is a decision-making technique that assigns weights to different criteria and calculates an overall performance score of the alternatives. By assigning relative importance to each criterion, this method allows decision makers to objectively evaluate options and make informed choices. The weighted sum method combines the weighted scores of each criterion to obtain a comprehensive performance measure that enables a systematic approach to decision making. The method provides a structured framework for analyzing complex decision-making problems, finding applications in fields as diverse as project selection, supplier evaluation, and product design. Alternate parameters: Steel Alloy (AHSS), Aluminium Alloy (A7075 T6), Carbon Fiber/ epoxy laminate (CL), Titanium Alloy (Ti6Al4 V). Evaluation parameters: Tensile Strength (Mpa), Stiffness (Gpa), Damping capacity, Cost (Rs), CO2 Emission (Ton/Ton), Results: The Steel Alloy (AHSS) is in 1st rank. The Aluminium Alloy (A7075 T6) is in 4th rank. Carbon Fiber/ epoxy laminate (CL) is in 2nd rank. Titanium Alloy (Ti6Al4V) is in 3rd rank. The result is done by using the WSM method. Conclusion: sustainable automotive car body material in the Steel Alloy (AHSS) is in 1st rank. The Aluminium Alloy (A7075 T6) is in 4th rank. Carbon Fiber/ epoxy laminate (CL) is in 2nd rank. Titanium Alloy (Ti6Al4V) is in 3rd rank. The result is done by using the WSM method.

Research on the impact of traction rods on coupler separation in the middle locomotive of 20,000-tonne heavy-haul trains

Aiming at the coupler separation problem in the middle locomotive of 20,000-tonne heavy-haul trains in China, this study investigates the influence of the locomotive traction rod. A theoretical kinematic model was developed to compare the motion of locomotives equipped with single and double traction rods, and the mechanism of coupler separation was analysed. A dynamic model, considering the three-dimensional interaction of couplers, was also established to simulate the dynamic process of coupler separation during braking and release stages. The simulation results indicate that locomotives equipped with double rods (positioned at both sides of the car body) are more prone to coupler separation than those with single rods (placed at the middle of the car body). The pitch angle of the double-rod model reaches a maximum of 0.20° when the electric braking force is 200 kN, approximately 10 times that of the single-rod model. For double-rod locomotives prone to coupler separation, maintaining a coupler knuckle friction coefficient greater than 0.1 and an initial height difference of less than 50 mm can significantly reduce the risk of coupler separation.

The effect of RSW technological parameters to the properties of aluminium/steel hybrid joints

To reduce fuel consumption and costs, the lightweight construction of car bodies is a very important aspect. This is achieved by using high-strength steel and aluminium alloy base materials. The latest car bodies contain both steel and aluminium alloy, so it is necessary to develop a reliable joining technology between them. Several joining technologies were investigated, such as mechanical joining, adhesive joining, and welding too. Resistance spot welding (RSW) is typically used to join car body parts and can be used for aluminium/steel hybrid joints. During welding, a very brittle intermetallic compound (IMC) is formed, which basically determines the properties of the joint, which is particularly influenced by the thickness and phases of the IMC. EN AW 5754 H22/ DP600 dissimilar joints were made with RSW, using different welding parameters. The joints were tested by shear-tensile tests and the effect of the IMC layer was determined.

The Regression Models of Ultraviolet Rays Effect on Break Strain and Strain at the Ultimate Tensile Strength of Polypropylene Composite Materials

Many types of polymer materials used in engineering are exposed to ultraviolet (UV) light, including automotive components (car bodies, bumpers, dashboards, etc.) which will cause degradation. Some polymers are used in the form of pure polymers and some in the form of composite materials. This study aims to determine the occurrence of degradation in composite materials. This study used polypropylene as a matrix in the composite material sample, while oil palm fiber was used as a reinforcement. This research investigates the degradation of composite materials due to exposure to ultraviolet light. In this research, the degradation of the specimen samples was measured based on changes in Break Strain (BS) and Strain at the Ultimate Tensile Strength (SUTS), related to the length of UV exposure based on 6 different levels of UV exposure, i.e.: 0 hours (UV unexposed), 96 hours, 336 hours, 504 hours, 1008 hours, and 1512 hours. Then the test resulted data was used to generate a strain regression model of BS and SUTS it was obtain from this reaserch that regression model of SUTS is : Y1 = -3.10-9x3 + 7.10-6x2 - 0.0067x + 14.706 with R² = 0.9894 and regression model of BS is : Y2 = 10-8x3 + 2.10-5x2 - 0.0161x + 50.287 with R² = 0.9961. Furthermore, these regression models can be used to predict the maximum strain, of composite materials exposed to UV light for some many time length, which can later be used, to determine the lifetime of the material.

Self-Powered Actively Controlled Lateral Suspensions of High-Speed Trains Using Energy-Regenerative Electromagnetic Damper and Model Predictive Control

Although traditional active suspension can offer superior riding comfort and maneuverability over its semiactive and passive counterparts, its reliance on an external power supply has hindered its widespread applications in vehicles. To overcome this deficiency, this paper proposes an innovative self-powered active suspension design for a high-speed train (HST), by leveraging the recently emerging H-bridge circuit-based electromagnetic damper (HB-EMD), allowing bidirectional power flow between the damper and controlled system. The capability of HB-EBD to achieve unique self-powered active skyhook control was previously proved in a simplified single degree-of-freedom (SDOF) structure under harmonic excitations; however, the feasibility of employing HB-EMD to realize active vibration control for more complex structural systems under stochastic excitations remains an unanswered question. One main challenge is designing a novel control algorithm that can simultaneously realize vibration control and self-powering objectives, which is unattainable by traditional active control algorithms. In this study, an ad hoc model predictive controller (MPC) is designed to guarantee the fulfillment of these dual objectives. To evaluate the performance of the proposed active suspension design, two separate HB-EMDs are implemented on the front and rear sides of the secondary lateral suspensions of an HST model subjected to stochastic track irregularities. At a speed of 200[Formula: see text]km/h, the proposed HB-EMDs with MPC could achieve a 55% reduction in the lateral acceleration of the car body in comparison with passive suspension, meanwhile maintaining energy harvesting performance with an average output power of 25.0[Formula: see text]W. In contrast, a traditional active linear quadratic Gaussian (LQG) controller consumes 72.7[Formula: see text]W power when performing comparable vibration reduction. This study, for the first time, validates the feasibility of designing a self-powered, actively controlled secondary lateral HST suspension system without relying on an external power source, which will potentially pave the way for a new active vibration control paradigm for other generic structures.

Production control with Reinforcement Learning for a matrix-structured production system

With increasing product complexities in mass customisation in the automotive industry, the downsides of conventional production concepts like flow production get more pronounced. Their inability to deal with cycle time losses adequately opens up possibilities for new concepts like matrix-structured production (MSP). Due to the immanent dynamics of matrix-structured production, control concept like takt binding or control stands are no longer sufficient to achieve near-optimal performance. The application of Reinforcement Learning (RL) to solve this problem emerged in the recent years. In particular, routing and dispatching tasks have been solved by applying RL. As both tasks influence each other's performance, a combined RL approach is developed. Therefore, a car body construction is simulated to test different modelled Markov processes, algorithms, and rewards. The new approach is validated against common heuristics regarding logistic performance and relevant metrics for operating autonomous guided vehicle fleets. For this, RL systems are designed and compared. The combined approach of production control in terms of dispatching jobs and routing autonomous guided vehicles achieved equivalent performance to heuristics. Still, it excelled in fleet operation metrics, like reduced live or deadlocks.

Effect of Vehicle Vibration on Interior Noise of Railway Vehicles Passing Through Rail Corrugation Sections

This study involved experimental research to analyze the effect of rail corrugation on interior noise levels inside railway vehicles. Measurements taken on the Incheon Line 2 light rail indicated that the vehicle’s age and maintenance condition have minimal effects on interior noise. Although wheel wear slightly reduces interior noise, it is insufficient to address the issue of abnormal noise. The analysis of the relationship between vehicle vibrations and interior noise revealed that at 80 km/h and with a 24 mm rail corrugation wavelength, vibrations at 920 Hz in the axle box and car body increase, coinciding with the dominant interior noise frequency of 926.6 Hz. Furthermore, an analysis using a car body sweep confirmed a relative increase in noise in the 920 Hz range. Therefore, abnormal noise in rail corrugation sections is caused by vibrations at 920 Hz due to the corrugation wavelength and train speed, which align with the car body resonance frequency, leading to increased car body vibrations and interior noise.

Pengaruh Tipe Mobil Terhadap Harga dan Kapasitas Mesin di Belarus Dengan Pendekatan Metode Manova

Belarus is a country on the European Continent that continues to develop modern technology, especially in the field of the transportation industry. Supported by people's consumption patterns that tend to be consumptive where the demand for goods can affect the country's economy if not controlled properly, one of which is the use of cars. The high interest of the public in the use of cars is influenced by the design of the body type. Body type plays an important role in determining consumer preferences. The design of the car body type also affects the selling price. Engine capacity is also closely related, where larger vehicles typically have larger tanks. Therefore, it is important to analyze the influence between car body type and price and car engine capacity in Belarus using the multivariate analysis of variance (MANOVA) method. Data analysis starts from describing the characteristics of variables, then conducting MANOVA assumption testing starting from multivariate normality testing with Q-Q plot and T-proportion test, independence correlation test test with barlet test, and homogeneity test with box's m test. Followed by the MANOVA test on the body variable on the price and capacity of the car engine and after that the LSD test. The results of the price characteristics and the capacity of the car engine were obtained by one and two outliers, respectively, and the shape of the boxplot was asymmetrical The most observed type of car was the universal type. The results of the MANOVA assumption test show that the data is normally distributed multivariate, dependent, and has a homogeneous covariance variance matrix. The results of the MANOVA test show that there is at least one type of car that has a significant influence on the price and capacity of the car engine. The LSD test results show the type of car based on the price of the car that there is no difference between the average car type 1, 2, 3, 4.

Research on the process parameters and welded joint quality of resistance spot welding of aluminum composite for car bodies

Abstract The test uses a resistance welding machine to implement resistance spot welding of 6061-T6 aluminum alloy thin plate for automobile body and obtains the welding process parameters of resistance spot welding through the test. Using an orthogonal test scheme and extreme difference analysis method to test and further optimize the resistance welding process parameters, after lap resistance spot welding of a 6061-T6 aluminum alloy thin plate with a thickness of 2 mm, we analyze the welding appearance and complete the tensile test. The test results show that when the welding current is 60 KA, the welding pressure is 0.63 MPa, the thickness of the plate is 2.00 mm, the spot weld joints obtained from the specimen have no obvious defects, better molding, good welding quality and appearance, and its tensile shear value is 5.583 KN at maximum.

The toughness of polymer reinforced pineapple-leaf fibers for the electric car body application

Abstract Pineapple-leaf fiber (PALF) belongs to the plant-based fiber group that has been highly abundant recently. However, PALF was no longer used and thrown away as agricultural waste. In fact, PALF can be used as alternative reinforcement for composite materials due to its properties. Composite materials have been used in the aircraft, automotive and household furniture industries. The objective of this research was to investigate the impact properties of epoxy resin matrix reinforced with glass fiber and PALF. The ASTM D256-23 standard was carried out when performing the impact test. The result showed that the composite material consists of PALF had higher impact strength compared to the composite reinforced by glass fiber. The compatibilities of fiber and matrix became main factor that affect significantly the value. This was confirmed by the porosities test results. Therefore, PALF was proven its reliability to substitute the synthetic one such as glass fiber to strengthening the composite materials for electric vehicle body application.

Improvement of the Assembly of Automobile Bodies by the Adhesive-Threaded Technology

Improvement of the Assembly of Automobile Bodies by the Adhesive-Threaded Technology

Galvanic Corrosion Behavior of CFRP/Galvannealed Steel Coupling and Corrosion Inhibition

In recent years, environmental regulations for automobiles are getting stronger every year. To comply with these regulations, there is a strong need to reduce the weight of automobiles, which will lead to improve fuel economy and increase cruising range. Carbon fiber reinforced plastics (CFRP), a lightweight and high-strength material, is attracting attention as a material for the next generation of vehicles. A multi-material car body using CFRP in combination with conventional metal materials is effective in reducing the weight of automobiles. However, galvanic corrosion occurs when different materials come into electrical contact in a corrosive environment. Therefore, Inhibition of galvanic corrosion is essential for practical use of CFRP. In this study, galvanic corrosion behavior of CFRP/galvannealed steel coupling was investigated, and galvanic corrosion inhibition technology was developed. CFRP (3K plain weave, epoxy resin) and galvannealed steel (GA) were prepared. CFRP was used on the surface and cross-section. GA was used on the surface as received and the surface of base-steel where the plating layer was removed by polishing. Galvanic corrosion tests were measured in 0.1 M NaCl saturated with air. A scanning electron microscope equipped with an energy dispersive X-ray spectroscopy system was used to observe the surface of the specimens.

Corrosion Resistance of Zinc Alloy Coatings Containing 1-3wt% Mg and Al at Small Radius Bends

Environmental targets to increase the whole-life efficiency of many products have led to an increased focus on improvements in metallic coating performance, with view to increase durability and minimise consumption of raw materials. Zinc Magnesium Aluminium (ZMA) alloy galvanised coatings have been the focus of numerous research studies over the past two decades. Research has predominantly been based around the improved corrosion resistance of these coatings for automotive and construction products exposed to external environments. A variety of compositions exist, each forming complex microstructures containing primary zinc within eutectics rich in magnesium and aluminium. These compositions generally include, but are not limited to, alloy additions that range between 1 and 2 wt% to zinc. The alloying additions enhance the corrosion resistance and pressing performance. It has been previously identified that limited systematic research has been undertaken to date to understand what influences adverse mechanical behaviours of these microstructures. Studies have shown that eutectic phases are susceptible to cracking on forming. More recent research has attributed the genesis of the cracks, specifically to the twinning locations within the eutectic phase, MgZn2.This study investigates four Zinc Alloy coatings containing: 1Mg1Al; 3Mg3Al; 1Mg3Al and 3Mg1Al wt% additions. These compositions formed different morphologies, with varying volumes of primary and eutectic phases. All four specimen coatings are approximately 30 microns thick and have been created using identical heat treatment processing parameters and cycle. The galvanic alloy coatings have been mounted upon 0.7mm gauge Interstitial Free (IF) steel substrate. This substrate has been selected as typically used for car body panels in the automotive industry, and cold formed light gauge structural sections in the construction industry. IF steels offer good tensile strength, as well as good formability capability. A Hot Dip Processing Simulator was used to apply the IF steels with the four separate specimen coatings, to isolate variables, such as: substrate grade, substrate thickness, coating thickness, heat treatment cycles and post coating cooling.Uniaxial tensile tests are governed by the structural substrate mechanical properties. Typically, with elongation limits of approximately 20%. Traditional soft-tempered galvanic coatings can achieve as much as 65% elongation, which is desirable when forming pre-galvanised sheet material. However, bending material presents a stress distribution of both tension and compression. Elongations as much as 100% (theoretical 0T bend) can be induced on the coated material surface, without total structural failure of its substrate. BS EN 13523-7 provides a Standard for testing and specifying a minimum bend radius for coated sheet material. As bend radius and material thickness govern bending tensile strain, bends are categorised relative to material thickness.A systematic study was undertaken that incrementally induced relatively high levels of strain to the material surface, by bending the pre-coated steel sheet material. The cracked microstructures of the four zinc alloy coating specimens were quantified before accelerated corrosion tests were undertaken. All specimen samples were immersed in 1wt% NaCl electrolyte solution and test data recorded over a 24-hour period, at room temperature. A GAMRY Potentiostat recorded Open Circuit (OCP) and Linear Polarisation Resistance (LPR) data of both strained and unstrained samples and results were compared.The results showed that for a comparable strain, each of the cracked coating specimens were cathodically polarised. The depths of coating cracks were observed using a scanning electron microscope, during a fracture analysis exercise of cross-sectional images. The cracks were observed to be the full depth of the coating full thickness, exposing the surface of the steel substrate. The characteristics of the coating fractures correspond with the electrochemical test results. The corrosion resistance of these zinc alloy coating specimens was compromised when the coatings cracked on the tension surface at small radius bends, when compared to flat unstrained samples.

The Effects of Bismuth Addition on the Characteristics of Aluminum Alloys for Electric Vehicle Battery Housings

As the Electric Vehicle(EV) market has recently grown, the application of high-performance aluminum alloy, a representative lightweight material for lightening car bodies, is increasing. Among them, die casting is receiving the most attention due to its rapid productivity and excellent formability, and research on improving the properties of the mainly used Al-Si alloy is being actively conducted. In this study, the influence of additions of bismuth(Bi) on microstructure, thermal, and machinability of Al-10%Si alloy has been reported. Bismuth depressed the aluminum-silicon eutectic growth temperature and altered the silicon morphology. When the bismuth contents of the specimens were 0, 0.22, 0.5 and 1.8 wt%, results show that bismuth has a refining effect on the eutectic silicon and its refinement behavior is improved with increasing bismuth. Also bismuth is added to improve the mechanical and thermal properties of aluminium alloys for EV battery housing. Finally, we analyzed the heat emission characteristics and oxidation resistance of the battery housing using the developed aluminum alloy to study whether it could contribute to the stable operation of the battery.

Development of New Light-Dimming Film Using Black Electrochromic Inks

Windows serve the purpose of allowing people to see outside from inside. However, excessive sunlight and heat can enter through windows, disrupting the indoor thermal environment. In the case of vehicles, heat can accumulate quickly in the enclosed space, and temperatures on dashboards can exceed 80°C in summer, jeopardizing the comfort and safety of passengers and drivers without proper heat shielding measures. Our research group is developing a new light-dimming film that can be used for automotive applications. This light-dimming film uses electrochromic principles to produce color change and heat shielding properties through electrochemical effects caused by the application of voltage. This light-dimming film can be fabricated using a wet coating process, which is expected to be highly productive, low-cost, and easily applicable to large-area applications. We are developing a complementary device by combining Prussian blue (PB)-type complex nanoparticles and tungsten oxide (WO3) nanoparticles (NPs). In this prototype device configuration, the electrochemical response produces a colorless transparent state and a dark blue color change, and when colored, the transmittance in the near-infrared region can be reduced to 1% or less. When applied to automobile windows, the performance of cutting heat rays contained in sunlight under hot weather can reduce the air conditioning load, which is expected to reduce fuel consumption or electricity costs in EV vehicles. On the other hand, this dark blue colored state has design issues such as matching with car body color and luxury. To solve these issues, this research is exploring and developing new black electrochromic material such as CuO nanoparticles, etc. In PRiME, we report on the progress in the development of the black electrochromic materials.

Research on dynamic analysis and maintenance strategy for hard bending of high-speed turnout switch rail

Plastic deformation occurs in the turnout switch rail during loading, unloading, transportation, and storage, resulting in hard bending of the switch rail. The hard bending of the switch rail will lead to an abnormal increase in insufficient displacement, resulting in the geometric size exceeding the limit and the potential risk in the train operation. However, the dynamic simulation of the turnout area has not fully explored the potential impact of the insufficient displacement caused by the hard bending of the switch rail on driving safety. Therefore, this paper establishes a high-speed railway EMU-turnout dynamics model to evaluate the influence of the hard bending of the switch rail on the safety and stability of the train. The results show that the influence of theoretical and measured switch rail hard bending amplitude on the vehicle dynamics index is limited when it is 4 mm or less. However, when the hard bending amplitude of the switch rail increases to 8 mm, the relevant vehicle dynamics indexes increase significantly. The maximum derailment coefficients under the theoretical and measured hard bending of the 8 mm working conditions are 4.42 times and 6.71 times the normal working conditions, respectively. The wheelset lateral force is 4.55 times and 6.86 times the normal working conditions, but they are all within the safety limit. The on-site verification also confirms that there is no significant change in the vertical and lateral acceleration of the car body under the 4 mm hard bending of the switch rail. Finally, a maintenance strategy for the insufficient displacement caused by the hard bending of the switch rail is proposed and the effectiveness of the maintenance strategy is verified in the case study.

An improved multi-objective artificial physics optimization algorithm based on R2 indicator and its application

Artificial Physics Optimization (APO) algorithms in solving constrained multi-objective problems often encounter challenges such as uneven population distribution and imbalances between global and local search capabilities. To address these issues, we propose the Constrained Rank Multi-Objective Artificial Physical Optimization based on the R2 indicator (R2-ICRMOAPO) algorithm. This algorithm integrates non-dominated sorting with the R2 indicator and updates the external storage set using the contribution value derived from the R2 indicator formula, ensuring both set distribution and convergence. It also dynamically adjusts inertia weights and gravitational factors to enhance its global and local search capabilities. To evaluate the performance of the R2-ICRMOAPO algorithm, we compared it with four other multi-objective optimization algorithms using standard test functions. The results indicate that it demonstrates superior distribution and optimization performance. Furthermore, we applied it to optimize the parameters of a hydro-pneumatic suspension system. The experimental results show that it can reduce the root mean square value of car body vertical acceleration by approximately 21.4% and the root mean square value of dynamic tire load by about 19.6%. This reduction effectively enhances vehicle smoothness within a reasonable range. Consequently, these results confirm the feasibility of the R2-ICRMOAPO algorithm to solve practical problems.

Systematic Risk Analysis of Railway Component Quality: Integration of Failure Mode & Effect Analysis (FMEA) and Fault Tree Analysis (FTA)

Quality assurance is a critical aspect in the production systems, affecting product quality and safety. Defects and failures of manufactured components will diminish overall product quality, which could vulnerably risk consumer safety. This study focuses on quality assurance analysis of train component manufacturing systems. According to the quality control data, the number of defects recorded was about 10-12, on average, for each wagon produced. The defect mainly occurred while making the underframes, car body, and even the small components. This led to the tardiness of product delivery for 1-2 months. This study aims to analyze non-conformance report data and identify the potential failure modes, potential effects, and root causes. To do so, we integrated systematically FMEA (Failure Mode and Effect Analysis) and FTA (Fault Tree Analysis). First, RPN (Risk Priority Number) score was calculated to determine risk priority. Second, Pareto analysis was performed to select defects that most contributing to overall failures, which were then analyzed using FTA to obtain root causes. The results show that 8 defects exceed the critical RPN score of 209. Materials and personnel are identified as two major contributor failure events from three selected defects. The recommendation for further improvements is provided based on various defect categories to prevent similar defects. The findings demonstrate that the combined use of FMEA and FTA is effective in identifying failures and root causes within complex and long production cycle systems.