SJME KINEMATIKA Vol.
10 No.
2, 11 Agustus 2025, pp 228-241 https://kinematika.
id/index.
php/kinematika STUDI NUMERIK KEKUATAN BAHAN PADA STRUKTUR CHASSIS
DENGAN BEBAN STATIS DAN DINAMIS
NUMERICAL STUDY ON THE MATERIAL STRENGTH OF A MICROCAR
CHASSIS STRUCTURE UNDER STATIC AND DYNAMIC LOADS
Rahmatia.
Lizda Johar Mawarani.
Riyki Apriandi.
1,2Teknik Fisika.
Institut Teknologi Sepuluh Nopember.
Surabaya.
Indonesia 3Teknik Manufaktur.
Politeknik Batulicin.
Batulicin.
Indonesia email: tia522517@gmail.
, lizda@its.
*, riyki@politeknikbatulicin.
Abstrak Received:
23 Juni 2025 Accepted:
12 Juli 2025 Published:
11 Agustus Pertumbuhan kendaraan mikro .
sebagai solusi mobilitas perkotaan menuntut desain struktur yang efisien namun tetap kuat dan aman.
Penelitian ini bertujuan untuk menganalisis performa struktural chassis microcar menggunakan pendekatan simulasi numerik berbasis Metode Elemen Hingga (Finite Element Method/FEM) dengan perangkat lunak ANSYS Workbench.
Evaluasi dilakukan terhadap lima jenis materialAi Aluminium 6061-T6.
Aluminium 6082.
Steel AISI 1018.
Steel S355JR, dan Carbon Fiber Reinforced Polymer (CFRP) Prepreg melalui analisis statis dan dinamis.
Hasil simulasi menunjukkan bahwa semua material memiliki nilai safety factor di atas 1, dengan CFRP prepreg mencatat nilai tertinggi.
Material aluminium dinilai paling optimal untuk produksi massal karena ringan, cukup kuat, dan ekonomis.
Pada analisis dinamis, seluruh struktur menunjukkan respons aman terhadap beban getaran acak akibat ketidakteraturan permukaan jalan, meskipun terdapat potensi resonansi pada frekuensi tertentu.
Oleh karena itu, analisis kelelahan .
direkomendasikan untuk evaluasi jangka panjang.
Studi ini memberikan kontribusi penting terhadap perancangan chassis microcar yang ringan, aman, dan berkelanjutan.
Kata Kunci: microcar, chassis.
Finite Element Method, analisis statis, analisis Abstract The growth of microcars as an urban mobility solution demands an efficient yet strong and safe structural design.
This study aims to analyze the structural performance of microcar chassis using a Finite Element Method (FEM)-based numerical simulation approach with ANSYS Workbench software.
Evaluation was conducted on five types of materials-Aluminum 6061-T6.
Aluminum 6082.
Steel AISI 1018.
Steel S355JR, and Carbon Fiber Reinforced Polymer (CFRP) Prepreg through static and dynamic analysis.
Simulation results show that all materials have safety factor values above 1, with CFRP prepreg recording the highest value.
Aluminum is considered the most optimal material for mass production because it is lightweight, strong enough, and economical.
In the dynamic analysis, the entire structure showed a safe response to random vibration loads due to road surface irregularities, although there was potential for resonance at certain frequencies.
Therefore, fatigue analysis is recommended for long-term evaluation.
This study makes an important contribution to the design of lightweight, safe and sustainable microcar chassis.
SJME KINEMATIKA Vol.
10 No.
2, 11 Agustus 2025, pp 228-241 https://kinematika.
id/index.
php/kinematika Keywords: microcar, chassis.
Finite Element Method, safety factor, static analysis, dynamic analysis DOI: 10.
20527/sjmekinematika.
How to cite: Rahmatia.
Mawarani.
Apriandi.
AuNumerical Study On The Material Strength Of A Microcar Chassis Structure Under Static And Dynamic LoadsAy.
Scientific Journal of Mechanical Engineering Kinematika, 10.
, 228-241, 2025.
INTRODUCTION
Mobility problems in urban areas, such as limited parking space, high levels of congestion, and increasing public awareness of environmental issues have encouraged the emergence of more efficient vehicle solutions.
One solution that is becoming increasingly popular is the micro vehicle .
Microcars offer advantages in terms of space efficiency, fuel consumption, and lower carbon emissions compared to conventional vehicles.
In addition, government policies in various countries that support the development of environmentally friendly vehicles also accelerate the adoption of these vehicles in the global automotive market.
However, despite the advantages of microcars in terms of efficiency and sustainability, major challenges remain in terms of safety and structural strength, especially in chassis components.
The chassis serves as the main framework that supports the entire weight of the vehicle, integrates critical components such as wheels, engines, and suspension systems, and protects passengers from potential hazards.
In micro-vehicles, the chassis design must consider compact dimensions and light weight, while still being able to meet structural rigidity and safety standards.
The space and weight limitations of microcars require careful selection of chassis materials to maintain strength without significantly increasing vehicle weight.
Improper material selection can lead to increased energy consumption, reduced performance, and higher production and maintenance costs.
Since microcars are generally aimed at market segments that prioritize efficiency and affordability, economics is also an important consideration in chassis design.
To ensure that the chassis is able to perform optimally under various loading conditions, both static and dynamic structural analysis is required.
Static analysis is conducted to evaluate deformation and stress due to fixed loads such as vehicle and passenger weight.
Meanwhile, dynamic analysis is aimed at understanding the structural response to cyclic loads and vibrations during vehicle operation, as well as to anticipate potential material fatigue and resonance.
In addition, a safety factor is used to ensure that the design has adequate margin against structural failure.
This study aims to design a new chassis structure for a microcar that is lightweight, strong, and safe.
The design and evaluation process were carried out using numerical simulations based on the Finite Element Method (FEM) with the aid of ANSYS software.
The simulations include deformation analysis, stress distribution, and safety factor calculations under various loading conditions that represent the operational scenarios of the To support optimal material selection, five different types of materials were applied to the same chassis model to determine the most suitable one in terms of strength and weight The results of this study are expected to make a significant contribution to the development of microcars that are not only energy-efficient and environmentally friendly but also meet structural safety standards and support sustainable innovation in the automotive industry.
DESIGN
The microcar chassis design in this study uses a space frame type, which is considered more suitable for lightweight vehicles such as microcars because it offers high structural SJME KINEMATIKA Vol.
10 No.
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The design process was carried out using Autodesk Fusion 360 software, with the chassis dimensions referring to the standard size of microcars available in the market.
The frame profile used was a tubular frame with an outer diameter of 30 mm and a wall thickness of 2 mm, which was chosen to achieve a balance between structural strength and mass efficiency.
The design and dimensions of the microcar chassis structure are shown in Figure 1 and Figure 2.
Figure 1.
Microcar chassis design Figure 2.
Microcar chassis dimensions METHOD In this study.
ANSYS Workbench software was used to perform numerical simulations to evaluate the strength of the chassis structure due to static and dynamic loading.
The static loads analyzed include those from the electric motor and transmission components, the battery, and the weight of two passengers.
Meanwhile, the dynamic load used comes from the effect of road surface vibration, which is modeled based on the type A road profile according to ISO 8608 standard in the form of accelerated Power Spectral Density (PSD) Static loading analysis is performed using a static structural analysis approach, while SJME KINEMATIKA Vol.
10 No.
2, 11 Agustus 2025, pp 228-241 https://kinematika.
id/index.
php/kinematika dynamic loads are analyzed through modal analysis to obtain natural frequencies and vibration mode shapes, and random vibration analysis to evaluate the structural response to random excitation due to the road surface.
In this study, five types of materials were used as candidate materials for the microcar chassis, namely Aluminum 6061-T6.
Steel AISI 1018.
Steel S355JR.
Aluminum 6082, and Carbon Fiber Reinforced Polymer (CFRP) prepreg type.
The performance of the five materials is analyzed and compared through static and dynamic The overall weight of the microcar chassis by material type is presented in Table The material selection was based on the characteristics of mechanical strength, stiffness, and strength-to-weight ratio that support the structural performance of lightweight vehicles.
Data on the mechanical properties of each material is obtained based on references from previous studies.
which is presented in Table 2.
Table 1.
Mass of the chassis in each material type Material Chassis Mass .
Material Al 6061-T6 Steel AISI 1018 Steel S355JR Al 6082 CFRP Prepreg Aluminum 6061-T6 Steel AISI 1018 Steel S355JR Aluminum 6082 CFRP Pregreg Table 2.
Mechanical properties of each material YoungAos PoissonAos Yield Ultimate Modulus Ratio Strength Tensile (Gp.
(Mp.
Strength (Mp.
Density .
g/m.
Figure 3.
Static structural boundary conditions SJME KINEMATIKA Vol.
10 No.
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php/kinematika Static Analysis Static analysis of numerical simulations was performed using the Static Structural Analysis module in ANSYS Workbench software.
The chassis model was discretized using beam elements with a mesh size of 10 mm.
Beam elements are appropriate for framelike structures such as a vehicle chassis, as they efficiently represent slender members subjected to axial, bending, and torsional loads.
Boundary conditions are static loads from the electric motor and transmission, as well as the battery with a force of 2484.
8 N shown by the yellow arrow in Figure 3.
The load from two passengers of 1479.
2 N is shown by the red arrow in the same figure.
In addition, fixed support is also applied as illustrated in Figure 3.
To ensure the accuracy of the simulation results, a mesh convergence test was also performed, as shown in Figure 4.
The convergence was evaluated based on the variation of stress values with respect to changes in mesh size.
The graph in Figure 4 shows that the stress values have converged at a mesh size of 10 mm.
Static analysis is performed to obtain the structural response of the microcar chassis, which includes deformation, stress, and safety factor values.
Stress (MP.
Mesh Size .
Figure 4.
Mesh convergence Table 3.
Acceleration PSD of road profile type a based on ISO 8608 Spatial Frequency n Temporal Frequency f PSD Acceleration Ga.
(H.
/sA)A/H.
0 y 10AA 4 y 10AA 4 y 10AA 0 y 10AA 1 y 10AA 3 y 10AA 2 y 10AA 0 y 10AA 5 y 10AA 0 y 10AA SJME KINEMATIKA Vol.
10 No.
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id/index.
php/kinematika Acceleration PSD (.
/s.
2/H.
10Oe4 10Oe5 10Oe6 10Oe7 10Oe1 Frequency (H.
Figure 5.
PSD graph of acceleration vs frequency Dynamic Analysis Dynamic analysis in numerical simulations is performed using the Modal Analysis and Random Vibration Analysis modules in ANSYS Workbench software .
Modal analysis is used to determine the natural frequencies and mode shapes of the structure without the influence of external loads.
Therefore, this analysis only considers the structural mass of the microcar chassis as the source of inertia, without involving external loads such as passengers, motors, or batteries, while Random Vibration Analysis is utilized to evaluate the dynamic response of the structure to random excitation caused by road surface irregularities.
The dynamic load in Random Vibration Analysis uses a type A road profile according to ISO 8608 standard, which is represented in the form of accelerated Power Spectral Density (PSD) data.
Table 3 and Figure 5 show the Power Spectral Density (PSD) values of acceleration of type A roads according to ISO 8608 standard at an average urban vehicle speed of 50 km/h.
RESULTS AND DISCUSSION
Static Analysis The static simulation results on the microcar chassis in the form of deformation, stress, and safety factor on each material are shown in Table 4 and Figure 6.
Based on the simulation results, the chassis structure using prepreg CFRP material shows the highest deformation value, which is 2.
02 mm.
This indicates that the composite material is more prone to deformation when receiving static loads, as it has lower stiffness than other In contrast, the chassis made of steel materials such as AISI 1018 steel and S355JR steel showed a smaller deformation of 0.
6 mm.
This value reflects the higher level of rigidity in steel materials when compared to aluminum and composite materials.
The deformation distribution pattern of each chassis material is shown in Figure 7.
SJME KINEMATIKA Vol.
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2, 11 Agustus 2025, pp 228-241 https://kinematika.
id/index.
php/kinematika The simulation results show that the maximum stress values in the chassis structure vary depending on the type of material used.
Steel materials such as AISI 1018 steel and S355JR steel produce the highest stress values, which are 41.
03 MPa and 41.
04 MPa.
contrast, aluminium materials show slightly lower stress values, where Aluminium 6061-T6 has a value of 38.
11 MPa and Aluminium 6082 of 38.
07 MPa.
These values indicate that chassis using aluminium materials have good structural performance compared to steel materials, as they have higher ductility.
CFRP prepreg, as a composite material, showed the lowest stress value of 36.
87 MPa.
This indicates that the CFRP prepreg material has a better load-bearing capability than other materials.
Although the stresses that occur in the chassis with steel and aluminium materials are relatively higher, the stress value is still within safe limits because it is still below the yield strength value of each material.
The stress distribution pattern of each chassis material is shown in Figure 8.
Table 4.
Static simulation results Maximum Maximum Stress Deformation .
(Mp.
Chassis Material Aluminum 6061-T6
Steel AISI 1018
Steel S355JR
Aluminum 6082
CFRP Pregreg
Maximum Deformation Maximum Stress
Minimum Safety Factor
41,03
Minimum Safety Factor
41,04
38,11
38,07
36,87
1,67
Aluminum 6061-T6 Steel AISI 1018
Steel S355JR
1,64
2,02
Aluminum 6082 CFRP Pregreg Chassis Material Figure 6.
Graph of static simulation results The minimum safety factor value gives an idea of the extent to which a material is able to withstand loads before reaching its yield strength limit.
The higher the safety factor value, the greater the safety margin of the material against structural failure.
The minimum safety factor value allowed for structures subjected to a load is 1.
However, for structural safety, the minimum safety factor value is usually recommended for designs with a value >1.
Based on the simulation results, the prepreg CFRP material shows the highest minimum safety factor value of 15.
This means that this material can withstand loads more than 15 times its elastic limit before permanent deformation occurs.
AISI 1018 steel and S355JR steel have safety factors of 8.
8 and 8.
6, respectively, which are high and show good SJME KINEMATIKA Vol.
10 No.
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Both steel types have a good combination of strength and stiffness, making them suitable for structural applications that require high performance.
Meanwhile.
Aluminium 6061-T6 and Aluminium 6082 have lower safety factors of 7.
3 and 6.
Although the values are smaller than steel and CFRP prepreg, these figures still indicate that both aluminium materials remain within safe limits when receiving the applied load.
general, all materials have a minimum safety factor that is large enough, so it can be concluded that all materials tested are in a safe condition when experiencing loading.
However, the highest value of prepreg CFRP makes it superior in terms of safety margin against failure, especially in lightweight applications that prioritize efficiency and safety.
Based on the simulation results, all materials in the chassis have a minimum safety factor value of more than 1.
These results indicate that the chassis has a safety factor value that is sufficient for structural safety under loading.
Figure 7.
Deformation distribution pattern of static simulation results of each microcar chassis SJME KINEMATIKA Vol.
10 No.
2, 11 Agustus 2025, pp 228-241 https://kinematika.
id/index.
php/kinematika Figure 8.
Stress distribution pattern of static simulation results of each microcar chassis Dynamic Analysis Dynamic analysis of chassis structures has been conducted in several previous studies using a numerical simulation approach based on the finite element method.
,20,21,.
this study, 28 mode shapes were extracted to see the natural frequency of the chassis The number of mode shapes extracted is based on a value of 1.
5 times the maximum temporal frequency value in the acceleration PSD data, which is 138.
9 Hz.
The maximum value of 28 mode shapes is 210.
75 Hz which is enough to cover the range of the maximum dynamic load value in the acceleration PSD data.
In addition, the value of the number of 28 mode shapes is also based on data on the ratio of effective mass to total mass from the simulation results of modal analysis.
The 28 mode shapes extracted at least have a SJME KINEMATIKA Vol.
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Table 5 shows the natural frequency values and the ratio of effective mass to total mass of the chassis in each material.
The lowest natural frequency in each chassis material in mode shape 1 is in the range of 24 Hz to 30 Hz with the tendency of excitation in the Y axis rotation direction.
CFRP
prepreg chassis material has the highest average natural frequency value compared to other Based on the simulation results in Table 5, dynamic excitation tends to occur in the direction of Y or Z axis rotation.
Figure 9 shows the deformation pattern that occurs in mode shape 1 of the lowest natural frequency in each material.
Table 5.
Natural frequency Mode
Shapes Natural Frequency Excitation Al 6061-T6
Steel
AISI 1018
Steel
S355JR
Al 6082
CFRP
Y-axis rotation Y-axis rotation Z-axis rotation Y-axis rotation Y-axis rotation Y-axis rotation Z-axis rotation Y-axis rotation Z-axis rotation Z-axis rotation A A A A A A A Z-axis rotation Ratio of Effective Mass Based on the data from the random vibration simulation results in Table 6, the deformation and stress that occur are very small in the chassis structure in each material, this indicates that the random vibration effect load due to type A road excitation does not have a significant effect on the chassis structure.
Chassis materials other than prepreg CFRP composites are more deformed due to higher ductility.
Prepreg CFRP is more rigid, so the stress generated is also greater than other materials.
Table 6.
Random Vibration dynamic simulation results Chassis Material Maximum Deformation .
Stress Maximum (MP.
Alumunium 6061-T6 Steel AISI 1018 Steel S355JR Alumunium 6082 CFRP Prepreg Figure 10 shows the results of the PSD dynamic response of the chassis structure when dynamic loads are applied.
It can be seen in the figure, there is a possibility of resonance at SJME KINEMATIKA Vol.
10 No.
2, 11 Agustus 2025, pp 228-241 https://kinematika.
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php/kinematika certain frequencies marked by the appearance of peek as shown in the blue circle in the Although there is a possibility of resonance at certain frequencies, the simulation results show safe values of both stress and deformation that occur in each material.
This is evidenced by the very low maximum stress values of 0.
005 MPa, 0.
015 MPa, and 0.
MPa for each respective material, which are significantly below the yield strength values as shown in Table 2 of the mechanical properties.
Fatigue analysis can be performed to further observe the performance of the chassis structure due to dynamic loads that show resonance.
Figure 9.
Deformation pattern of the chassis in mode shape 1 SJME KINEMATIKA Vol.
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php/kinematika 10Oe1 Response PSD [.
/H.
10Oe2 10Oe3 10Oe4 17 Hz, 55,33 10Oe5 42 Hz, 71.
35 Hz, 75.
18 Hz 10Oe6 10Oe7 07 Hz, 119.
04 Hz, 43 Hz 10Oe8 10Oe9 10Oe10 15 Hz Oe11 99 Hz, 101.
69 Hz, 65 Hz Oe12 10Oe13 Frequency (H.
Figure 10.
Dynamic response of chassis structure CONCLUSION Static and dynamic simulation results show that the microcar chassis structure using aluminum 6061-T6, steel AISI 1018, and steel S355JR is able to withstand loads well, so no further design modifications or improvements are needed.
In general, aluminum material, especially aluminum 6061-T6 and aluminum 6082, is the main choice because of its lighter weight compared to steel.
Although the safety factor value of aluminum is relatively smaller, both are still within safe limits, especially Aluminum 6082 with a safety factor value of 6.
A safety factor value that is too high can cause material waste and increase production costs.
Therefore, selecting a material with an optimal safety factor is very important for cost efficiency and production sustainability.
Apart from being lightweight and safe, aluminum also has cost advantages as it is cheaper than steel and composite materials, making it an economical and efficient choice for mass production of microcar chassis.
Based on the results of the PSD dynamic response analysis of the chassis, there are indications of possible resonance at certain frequencies, indicated by the appearance of peaks in the response graph.
However, the resulting stresses and deformations are still within safe limits for all materials tested.
To ensure the reliability of the structure against long-term dynamic loads, fatigue analysis is required to evaluate the life and potential damage of the chassis structure, so that safety aspects can be maintained.
REFERENCE