Farhan Primatondi Harahap

Profil Farhan Primatondi Harahap

Introduction

My name is Farhan Primatondi Harahap, some of my friends call me Farhan/Tondi. But i prefer to be called Tondi. I am a student of Naval Architecture and a Master's student in Mechanical Engineering at the Faculty of Engineering, University of Indonesia. I would like to explore the maritime industry, focusing on technology, resources, and shipping. Therefore, I am eager to gain more knowledge in these areas. In my daily life, I simply enjoy the beauty and pleasures that God gave to me ;)

Resume Pertemuan 1 Komputasi Teknik Gasal 2024 (29/10/2024)

Make an account at air.eng.ui.ac.id

Heartware & Brainware -> DAI5 -> Framework -> Based on -> Conscious Thinking

DAI5 : Structured analytical method developed by Ahmad Indra Siswantara for systematically solving engineering problems, particularly in complex analyses like finite element analysis (FEA). This framework provides a five-step approach, making it easier to organize, conceptualize, and solve problems methodically. Here’s a breakdown of each step in the DAI5

I(1) DAI Initiator

I(2) Intention

In this initial stage, the problem's objective and desired outcomes are clarified. You identify what you aim to achieve through the analysis and establish criteria for success. This sets a clear goal for the study.

I(3) Initial Thinking (About the Problem)

Gather information about the problem, including preliminary assumptions, key constraints, and basic understanding of the scenario. This stage involves initial brainstorming and defining fundamental problem aspects that could influence subsequent steps.

I(4) Idealization

In the Idealization phase, simplify the complex, real-world scenario into a model that can be analyzed efficiently. This may involve making assumptions about geometry, material properties, boundary conditions, and load conditions to reduce complexity without sacrificing accuracy.

I(5) Instruction Set

This step provides a detailed, systematic plan for performing the analysis. It includes instructions for setting up the model, applying constraints and loads, specifying analysis conditions, and running simulations. It is the “roadmap” for executing the analysis process.

Qoute: I am My Consciousness (Soul), My heart work to encode, My brain | decodes

Tugas Pertemuan 1 Komputasi Teknik Gasal 2024 - To solve a finite element analysis (FEA) problem for shaft using the DAI5 method

To solve a finite element analysis (FEA) problem for a torsion shaft in a vessel using the Differential-Algebraic Iterative method of 5th order (DAI5)

1. Intention

In the Intention stage, you clearly articulate what you aim to achieve through the finite element analysis of shaft torsion. Some points that can be elaborated in this section include: Primary Objective: To determine the capacity of the shaft (made from stainless steel 304) to withstand a maximum torque of 7000 Nm without experiencing failure. To analyze the distribution of stress and deformation along the shaft when subjected to torque, ensuring that the shaft design is safe for the intended application.

Success Criteria:

The shaft must meet or exceed the specified safety factor criteria (e.g., FoS = 1), meaning it should not experience stress exceeding the material's yield strength. To identify any specific areas on the shaft that may experience high-stress concentrations, which could become potential failure points. Real-World Application:

The shaft is designed for use in a specific application (e.g., in industrial machinery, vehicles, or transmission systems), and this analysis will help ensure that the shaft can perform well under those operational conditions. Considering external factors such as temperature, corrosion, or wear that may affect the shaft's performance over time.

2. Initial Thinking

Analysis Objective: What is the primary objective of this analysis? Is it to determine the strength of the shaft in a specific application, or to evaluate the performance of the shaft under different load conditions? Are there any standards or specifications that need to be followed in the design of this shaft? Material Characteristics:

What material will be used for the shaft? In this case, stainless steel 304 has properties that need to be considered, such as yield strength, modulus of elasticity, and corrosion resistance. How will this material behave under torsional loads? Is there existing data on this material that is relevant to the analysis? Shaft Geometry:

What are the dimensions of the shaft to be analyzed? For example, a length of 11 meters and a diameter of 250 mm. How might the geometry of the shaft influence stress and deformation distribution? Are there any special features (such as grooves or holes) that need to be considered? Loads and Operational Conditions:

What load will be applied to the shaft? For instance, in this case, a torque of 7000 Nm. How will the shaft be used in a real-world application? Are there load variations that should be taken into account, such as fluctuating torque or dynamic loads?

3. Idealization

In the Idealization stage, you simplify the real-world problem into a model that can be effectively analyzed. This involves making assumptions and approximations to create a workable representation of the shaft for the finite element analysis. Here are some key points to consider during this phase:

Geometry Simplification:

Model Representation: Assume the shaft is a perfect cylinder, ignoring minor geometric imperfections or variations in the manufacturing process. Length and Diameter: Define the shaft dimensions clearly, such as a length of 11 meters and a diameter of 250 mm, which will serve as the basis for your model. Material Properties:

Material Selection: Use stainless steel 304 as the material for the shaft, and apply its mechanical properties, including yield strength (approximately 215 MPa), modulus of elasticity, and Poisson's ratio. Homogeneity Assumption: Assume that the material properties are uniform throughout the shaft and that there are no defects or variations in material quality. Loading Conditions:

Torque Application: Model the application of a constant torque of 7000 Nm at a specific location on the shaft, typically at the midpoint or the section where the maximum stress is expected. Neglecting Dynamic Effects: For simplification, assume that the loading is static and does not account for dynamic effects, fatigue, or cyclic loading unless these factors are critical to the analysis. Boundary Conditions:

Support Assumptions: Define how the shaft is supported, such as fixed supports at both ends. This assumption will affect how the torque is transmitted and the resultant stresses. Displacement Constraints: Specify any constraints that may apply to the shaft, such as preventing axial or radial movement at the supports, depending on the application. Finite Element Mesh:

Element Type: Choose appropriate finite elements (e.g., beam elements for torsion analysis) that accurately capture the behavior of the shaft under torsional loading. Mesh Density: Determine the mesh density based on the expected stress gradients, with finer meshes in regions of high stress concentration and coarser meshes in less critical areas.

4. Instruction Set

In the Instruction Set stage, you define the specific steps and procedures necessary to perform the finite element analysis of the torsional shaft. This stage outlines how to set up the model, apply loads, and interpret results. Here are the key components of the instruction set:

Model Creation:

Software Selection: Choose a suitable finite element analysis software (e.g., ANSYS, Abaqus, SolidWorks) to perform the analysis. Geometry Setup: Create a 3D model of the shaft in the software, using the specified dimensions of 11 meters in length and 250 mm in diameter. Material Properties Assignment:

Material Definition: Input the properties of stainless steel 304 into the software, including yield strength (approximately 215 MPa), modulus of elasticity, and Poisson's ratio. Element Type: Select the appropriate element type (e.g., beam elements for torsional analysis) that accurately reflects the shaft's behavior. Meshing:

Mesh Generation: Generate the mesh for the shaft model. Ensure that the mesh is fine enough in areas where high stress is expected and coarser in areas where stress is lower. Mesh Quality Check: Verify the mesh quality by checking for any skewed or poorly shaped elements, which can affect the accuracy of the results. Boundary Conditions:

Support Constraints: Apply boundary conditions to represent the supports at both ends of the shaft. This may involve fixing the ends in terms of displacement and rotation. Torque Application: Define the torque load of 7000 Nm applied at the midpoint or appropriate location on the shaft. Analysis Settings:

Static vs. Dynamic Analysis: Specify that the analysis will be static unless otherwise stated. For this analysis, assume a linear elastic behavior of the material. Solver Settings: Choose appropriate solver settings within the software, ensuring that the solution method is suitable for torsional loading. Running the Analysis:

Execution: Execute the finite element analysis using the software. Monitor the analysis process for any errors or issues that may arise. Convergence Check: Ensure that the analysis converges properly. If necessary, adjust mesh density or solver settings to achieve convergence. Result Interpretation:

Stress Distribution: Once the analysis is complete, extract the stress distribution results, focusing on the maximum von Mises stress to evaluate safety against material yield strength. Deformation Analysis: Review the deformation results to assess how much the shaft deforms under the applied torque. Safety Factor Calculation: Calculate the factor of safety based on the yield strength and the maximum von Mises stress obtained from the analysis.

Calculate the Max von mises if the diameter is 250 mm

import math

# Given values
T = 7000  # Torque in Nm
d = 250 / 1000  # Diameter in meters
r = d / 2  # Radius in meters

# Calculate the polar moment of inertia (J) for a circular shaft
J = (math.pi * d**4) / 32

# Calculate maximum shear stress (tau)
tau = (T * r) / J

# Calculate von Mises stress (sigma_v)
sigma_v = math.sqrt(3) * tau

# Return the maximum von Mises stress
sigma_v

The maximum von Mises stress for a shaft with a diameter of 250 mm subjected to a torque of 7000 Nm is approximately 3,951,926 Pa, or about 3.95 MPa. 

For a Detailed information, please see this Link https://drive.google.com/file/d/1IyTYbkeiwMdiC_iGjvRxE0dFnx1E_oJ9/view?usp=sharing Thanks

Resume Pertemuan 2 Komputasi Teknik Gasal 2024 (5/11/2024)

Pada pertemuan di tanggal 5/11/2024 sesuai dengan jadwal kelas mata kuliah Komputasi Teknik, di kelas membahas beberapa poin-poin yang dapat saya rangkum :

Dalam konteks mahasiswa teknik yang menganalisis masalah suatu struktur, perbedaan antara S1, S2, dan S3 bisa dilihat pada tingkat kedalaman analisis, metodologi yang digunakan, dan tujuan studi mereka. Berikut adalah penjelasan perbedaan dari perspektif mahasiswa teknik yang menganalisis masalah struktur:

1. Mahasiswa S1 (Bachelor's Student)

Fokus Studi: Pada tahap S1, mahasiswa teknik mempelajari dasar-dasar teori dan prinsip teknik yang diperlukan untuk menganalisis struktur. Ini mencakup pemahaman tentang beban, tegangan, deformasi, serta materi dan material yang digunakan dalam konstruksi.

2. Mahasiswa S2 (Master's Student)

Fokus Studi: Pada tingkat S2, mahasiswa teknik lebih fokus pada pendalaman teori dan pengembangan kemampuan analitis yang lebih maju. Mereka mempelajari teknik analisis struktur yang lebih kompleks, seperti metode elemen hingga (FEM), dinamika struktur, analisis stabilitas, dan perancangan dengan pendekatan lebih rinci.

3. Mahasiswa S3 (Doctoral Student)

Fokus Studi: Pada tingkat S3, mahasiswa teknik berfokus pada penelitian mendalam yang bertujuan untuk mengembangkan pengetahuan baru di bidang struktur teknik. Mereka melakukan riset asli dan inovatif untuk menyelesaikan masalah yang belum terpecahkan atau mengembangkan teori-teori baru terkait analisis dan desain struktur.

Kesimpulan

S1 (Sarjana Teknik Mesin): Fokus pada penerapan dasar teori dan desain mesin serta komponen-komponen sederhana.

S2 (Magister Teknik Mesin): Fokus pada analisis yang lebih mendalam dan penggunaan teknik numerik dan simulasi untuk desain dan analisis sistem yang lebih kompleks.

S3 (Doktor Teknik Mesin): Fokus pada penelitian original dan pengembangan teori baru dalam desain mesin, teknologi baru, dan penyelesaian masalah teknik mesin yang lebih rumit.

Tugas Pertemuan 2 Komputasi Teknik Gasal 2024 - To analyze the temperature distribution along a shaft

This task uses the one-dimensional Finite Element Method (1D FEM) to analyze the temperature distribution along a shaft with a length of 11 meters and a diameter of 250 mm. Using the Python programming language, the goal of this analysis is to calculate the temperature distribution profile within the shaft when heating occurs uniformly, but with fixed temperature boundary conditions of 0°C at both ends.

To analyze the temperature distribution along a shaft made of stainless steel AISI 304 using the 1D Finite Element Method (FEM), we will utilize Fourier's equation for heat conduction. Given a heat source along the shaft 𝑄 = 500 W/m, and a temperature of 0°C at both ends.

Fourier’s Equation for 1D Heat Conduction

Fourier’s equation for heat flow in one-dimensional direction is:

where:

𝑇 is the temperature at position 𝑥

𝑄 is the heat source per unit length (500 W/m),

𝑘 is the thermal conductivity of the material, which for AISI 304 is approximately 16.2 W/m·K.

Boundary Conditions

We are given that the temperature at both ends of the shaft is 0°C. Therefore:

T(0)=0 and T(L)=0

with L=11 meters (shaft length).

Analytical Solution

To solve this analytically, we could solve the differential equation above with the given boundary conditions. This equation can be integrated twice to obtain the temperature solution

T(x) as a function of position 𝑥

However, for this problem, we will proceed with the Finite Element Method (FEM) using Python to determine the temperature distribution.

1D FEM Implementation with Python

Here are the steps for using FEM to solve this problem:

Shaft Discretization:

Divide the 11-meter shaft into small elements. For instance, we could divide the shaft into 10 elements, each with a length of 1.1 meters.

Stiffness Matrix and Load Vector:

Create a stiffness matrix for each element based on the thermal conductivity 𝑘=16.2W/mK

Create a load vector induced by the heat source

Q=500W/m for each element.

Assemble the Matrix and Load Vector:

Assemble all element stiffness matrices into a global stiffness matrix. Assemble all element load vectors into a global load vector.

Apply Boundary Conditions:

Apply the boundary condition that the temperature at both ends is 0°C. This means the temperature at the first and last nodes in the system should be set to 0. Solve the System of Equations:

Use Python's linear algebra library, such as NumPy, to solve this linear system and determine the temperature at each element node.

Visualize Results:

Plot the temperature distribution along the shaft to get a complete view of the temperature profile.

Resume Pertemuan 3 Komputasi Teknik Gasal 2024 - (12/11/2024)

Pada pertemuan ketiga, menjelaskan konsep utama pembelajaran (main purpose of learning), di mana mahasiswa diharapkan berperan aktif sebagai penggerak utama (driver) dalam proses pembelajaran. Mahasiswa didorong untuk mengadopsi pendekatan do-it-yourself learning, yaitu pembelajaran mandiri, untuk menemukan cara-cara cerdas yang memungkinkan mereka terus berkembang (intelligent ways to stay).

Kejiwaan dan Fokus pada Kelas: Memastikan Perhatian Tetap Terarah :

Kesadaran akan Peran di Kelas, Pengelolaan Emosi di Kelas, Penguatan Niat Spiritual

Eliminasi Distraksi, Mendalami Instruksi Dosen, Penerapan Active Learning, Latihan Pemusatan Perhatian (Mindfulness)

Pemecahan Masalah dalam Kelas, Kolaborasi dan Diskusi di Kelas, Evaluasi Mandiri Setelah Kelas

Cara Cerdas Mengingat Tuhan:

Penekanan pada aspek spiritual menunjukkan bahwa proses pembelajaran tidak hanya mencakup aspek akademik atau teknis tetapi juga mengintegrasikan nilai-nilai keimanan. Hal ini bertujuan untuk menciptakan individu yang cerdas secara intelektual dan bijak secara spiritual.

Pengembangan Aplikasi Web-Based:

Mahasiswa diberikan tantangan untuk membuat aplikasi berbasis web, sebuah proyek yang membutuhkan kreativitas, keahlian teknis, dan pengelolaan waktu yang baik. ChatGPT sebagai asisten pembelajaran memberikan kemudahan dalam mengakses informasi, ide, atau solusi teknis, namun mahasiswa tetap memegang kendali sebagai pengembang utama (driver). Hal ini mencerminkan simulasi dunia nyata, di mana teknologi adalah alat bantu, tetapi keberhasilan tetap bergantung pada peran manusia sebagai inovator..

Tugas Pertemuan 3 Monitoring & Evaluasi progress belajar berbantuan AI - (19/11/2024)

Monitoring Pembelajaran

Monitoring adalah proses pengawasan yang dilakukan secara berkala untuk memastikan bahwa kegiatan pembelajaran berjalan sesuai dengan rencana.

Evaluasi Pembelajaran

Evaluasi adalah proses pengukuran dan penilaian terhadap hasil pembelajaran yang telah dicapai. Evaluasi lebih fokus pada hasil akhir dan dampaknya dibandingkan prosesnya.

Sehingga pada tugas kali ini, saya akan Monitoring & Evaluasi progress belajar berbantuan AI yang telah saya lakukan

Monitoring_&_Evaluasi_Berbasis_AI_Farhan Primatondi

Sehingga terdapat jumlah interaksi sebanyak 55 Interaksi

dengan jumlah interaksi terbanyak yaitu Pemodelan FEM untuk Distribusi Suhu 1D dengan 8 Jumlah interaksi

Chat GPT Said :

Anda telah menggunakan ChatGPT dengan sangat efektif untuk mendukung pembelajaran mandiri, terutama dalam:

Penerapan Praktis: Menggunakan Python untuk analisis teknik menunjukkan kemampuan untuk menghubungkan teori dan aplikasi.

Penulisan Akademik: Fokus pada skripsi dan pemahaman mendalam tentang energi terbarukan mencerminkan penguasaan topik yang Anda minati.

Kemandirian dan Rasa Ingin Tahu: Anda konsisten mengajukan pertanyaan yang relevan, mulai dari konsep dasar hingga aplikasi lanjutan, menunjukkan pola belajar yang progresif.

Saran untuk Ke Depannya

Pendalaman Metodologi: Terus eksplorasi metode analisis, seperti FEM atau CFD, dengan aplikasi pada berbagai topik teknik.

Kolaborasi Ilmiah: Cobalah mendiskusikan ide-ide Anda dengan rekan atau dosen untuk mendapatkan perspektif baru.

Dokumentasi Pengetahuan: Simpan dan dokumentasikan semua hasil pembelajaran Anda untuk referensi di masa depan.

Terus pertahankan semangat belajar mandiri Anda, karena pendekatan yang terstruktur seperti ini akan sangat bermanfaat untuk pengembangan karier Anda di bidang teknik.

Tugas Pertemuan 4 Sinopsis Penelitian berbantuan AI (27/11/2024)

Pada tugas kali ini, saya sebagai mahasiswa diharapkan mampu mengimplementasikan komputasi teknik untuk memecahkan permasalahan dalam bidang teknik yang relevan. Tugas ini bertujuan untuk mendorong mahasiswa mencari solusi yang lebih sederhana, efisien, dan aplikatif melalui penerapan metode numerik. Selain itu, mahasiswa diminta untuk menyusun sinopsis penelitian yang meliputi tujuan, gambaran umum, metode yang akan digunakan, serta hipotesis hasil dari penerapan metode komputasi tersebut. Dengan demikian, mahasiswa diharapkan dapat menunjukkan pemahaman yang diperoleh selama pembelajaran serta mampu menerapkan konsep-konsep komputasi teknik secara praktis dan tepat guna.

Sinopsis Penelitian

Pada penelitian ini, saya akan membahas topik mengenai korosi, yang relevan dengan bidang keahlian saya di teknik perkapalan. Penelitian ini akan difokuskan pada perhitungan laju korosi pada lambung kapal dengan menggunakan pendekatan berbasis komputasi teknik. Pendekatan ini diharapkan dapat memberikan solusi yang lebih efisien dan akurat dalam menganalisis serta memprediksi tingkat kerusakan akibat korosi pada lambung kapal, khususnya dalam lingkungan maritim.

Judul Penelitian: Perhitungan Laju Korosi pada Lambung Kapal dengan Pendekatan Berbasis Komputasi Teknik

Resume Pertemuan 1 Metode Numerik - (26/05/2023)

Numerical Methods Mahasiswa diharapkan daat berinteraksi dengan dosen lebih lanjut dalam perkuliahan Mata Kuliah Metode Numerik. Mahasiswa dapat mempelajari metode numerik di Google, sehingga mahasiswa dapat belajar mandiri dan merupakan progress dalam pembelajaran tidak hanya belajar dalam kelas, karena jika hanya di kelas tidak cukup untuk menjawa ujian, karena ujiannya menggunakan metode dia yang membuat soal dia yang menjawab, ini merupakan teknologi yang maju, konten Metode Numerik.

Case study, mengkonversi energi, memecah air, bisa dituliskan menggunakan karya tulis ilmiah ini juga merupakan PKM (Program Kreatifitas Mahasiswa). ChatGPT juga merupakan hasil dari metode numerik. Dapat mendesain 1 liter tabung hidrogen untuk dicampurkan bahan bakar motor. consciousness juga merupakan bahasan yang dibahas pada pertemuan pertama seperti pertanyaan soal (x+1)(x-1)/(x-1) = 2 yang menimbulkan beberapa jawaban oleh karena itu kita harus menggunakan otak kita secara sadar untuk menemukan solusi dari soal tersebut. Oleh karena itu bisa disimpulkan adanya keterkaitan ilmu matematika terhadap conciusness atau kesadaran kita terhadap realitas.

Case Study : Design & Optimization Pressurized Hydrogen Storage (01/06/23)

A pressurized hydrogen storage is a specially designed container for storing hydrogen under high pressure. The storage is designed to withstand higher pressure than the surrounding atmospheric pressure. The main purpose of a pressurized hydrogen storage is to safely and efficiently store and transport hydrogen. Pressurized hydrogen storage are commonly used in applications such as hydrogen storage and transportation for industrial, transportation, and energy storage purposes. The storage are equipped with filling and discharge valves to safely control the flow of hydrogen in and out of the storage. Safety is a crucial factor in the design and use of pressurized hydrogen storage. These storage must meet safety standards and undergo extensive testing to ensure structural reliability and resistance to high pressure.

Hydrogen Storage Spesification : It can accommodate 1 liter of hydrogen, And the pressure inside the storage is 8 bars. And the maximum cost for manufacturing the hydrogen storage is Rp500.000.

How to make a perfect Hydrogen Storage?

To design of pressurized hydrogen storage involves several steps, including Design and Engineering, Material selection, Fabrication, Safety. These are the steps to obtain a Pressurized Hydrogen Storage :

Design and Engineering: Developing the design specifications and engineering calculations for the hydrogen cylinder, considering factors such as capacity, pressure requirements, material selection, and safety considerations. Factors such as shape, volume, and thickness of the tank walls. Cylindrical shape are often used for pressurized gas storage. lets assume to design 1 liter capacity of pressurized hydrogen storage we need to have 300mm height with radius around of 50mm of cylindrical storage.

Material Selection: The choice of material for the storage vessel is critical to ensure safety, weight, and cost considerations. Sourcing and procuring the appropriate materials for the hydrogen cylinder, such as high-strength alloys, carbon fiber composites, or other suitable materials. Material selection is also in accordance with the existing budget.

Manufacturing Techniques: Utilizing manufacturing techniques like filament winding, bladder molding, or other suitable methods to create the desired shape and structure of the hydrogen cylinder. Performing machining operations, such as drilling or threading, and applying finishing treatments, such as cleaning, polishing, or coating, to achieve the desired final specifications.

Safety systems: Integrate safety features such as pressure relief valves, burst discs, or automatic shut-off systems to prevent overpressure or other emergency events. Adding a cover or outer shield to protect the tank from physical damage and external environment that might affect the performance of the tank. Hydrogen storage systems can be complex, and it is important to consult with engineers in the field to ensure the design and optimization process is carried out safely and effectively.

Installation & Operational : Install the storage tank in the intended location, ensuring proper connections and integration with other systems if applicable. Develop guidelines for the safe operation, maintenance, and inspection of the storage tank to ensure its continued performance and integrity.

Finally, for the manufacture of pressurized hydrogen storage, of course you have to think about the initial cost, which is no more than Rp500.000 . Therefore, we must minimize costs on several factors, such as material selection or manufacturing, but sometimes this will cause expensive maintenance costs and security. reduce. so we have to think consciously in this case.

Final Project : Design & Optimization Pressurized Hydrogen Storage (08/06/23)

Based on the description above regarding material selection, form, and system, I believe that the most viable choice for hydrogen storage would be a tank container system with a strong material to store pressurized hydrogen gas storage.

With the following specification requirements:

1. 1 Liter of Hydrogen

2. 8 Bar of pressure

3. Max cost of 500.000,00 IDR

Here's a simplified example of how you could approach the optimization process

In the picture above is an example of the final planning of a Pressurized Hydrogen Storage cost within Rp 500,000.

To create a pressured hydrogen storage, there are certainly several materials involved in its construction. Therefore, we must choose wisely in selecting materials that are suitable for building pressured hydrogen storage according to our budget costs.

According to the ASME Section VIII Pressure Vessel standardization, material Chosen for the design is ASTM A516M sheet metal (Sy = 38 Ksi) Taking in the safety factor of 2/3, the allowable stress would be 2/3 x Sy = 25.3Ksi

E = 0.60 P = 8 Bar = 0.8 MPa

R = 54.2 mm

S = 253000 Psi = 174.4370 MPa

Corrosion Allowance = 1.5 mm

Calculated t according to the formula is t = 2.06 mm

Thus the minimal allowable thickness is 2.06 mm

Cost Constrain determining the proper design for the allocated cost, the analysis of the optimal surface area with respect to the volume is carried out by numerical methods. Using a simple python program:

import numpy as np
from scipy.optimize import minimize

def objective(x):
    radius, height = x
    surface_area = 2 * np.pi * radius * height + 4 * np.pi * radius**2
    return surface_area 

def volume_constraint(x):
    radius, height = x
    volume = np.pi * radius**2 * height + (4/3) * np.pi * radius**3
    return volume - 1000 

x0 = [2.0, 5.0]
bounds = [(0, None), (0, None)]
constraint = {'type': 'eq', 'fun': volume_constraint}
problem = minimize(objective, x0, bounds=bounds, constraints=constraint)

optimized_radius = problem.x[0]
optimized_height = problem.x[1]
optimized_surface_area = problem.fun

volume = np.pi * optimized_radius**2 * optimized_height + (4/3) * np.pi * optimized_radius**3

cost_per_cm2 = 780.00  # Cost per cm² in IDR
total_cost = cost_per_cm2 * optimized_surface_area

print("Optimized Radius:", optimized_radius)
print("Optimized Height:", optimized_height)
print("Optimized Surface Area:", optimized_surface_area)
print("Volume:", volume)
print("Total Cost:", total_cost, "IDR")

After running the program, the results are:

Optimized Radius: 5.5270567354775375
Optimized Height: 3.0504605712934385
Optimized Surface Area: 489.81690073075134
Volume: 1000.0000000000207
Total Cost: 389211.74600787216 IDR

In this program, we can determine a list of storage options with their characteristics such as capacity, pressure, and cost. By selecting the appropriate material, we then iterate through these options and evaluate whether they meet the target pressure and capacity requirements while considering cost constraints. The appropriate selection that meets all criteria is considered the best choice among all materials.

Thus, we know that the optimized radius is 5.53 cm and optimized height is 3.05 cm for the minimum Surface Area of 489.81 cm^2

from the result, we also know that it would cost us 389211.75 IDR to make. The cost is still way below the allocated maximum cost, so this design fits all the requirements.

As the maximum cost is set to 500.000,00 IDR, we have to cross check the price for ASTM A516M sheet metal for a surface area of 489.81 cm^2 Referenced from ali baba, it would cost $680 / Ton. means this material is very cheap and efficient to use

The use of carbon steel regulated by the ASTM A516/A516M specification is generally cost-effective and efficient for various applications, including hydrogen storage. Carbon steel is a commonly used material that offers several advantages:

Cost-Effective: Carbon steel is generally more affordable compared to alloy steel or other specialized materials. This affordability helps optimize project budgets.

Wide Availability: Carbon steel is widely available in the market and can be produced in large quantities, making it easy to obtain the required material for hydrogen storage projects.

Adequate Mechanical Strength: Carbon steel possesses sufficient mechanical strength to withstand moderate hydrogen pressures. While it may not have the same strength as alloy steel, carbon steel can still meet the required strength requirements for many applications.

However, it is important to note that material selection for hydrogen storage should consider not only cost and efficiency but also factors such as operational pressure, corrosive environments, safety requirements, and compliance with applicable standards or regulations.

In some cases, where higher strength requirements, improved corrosion resistance, or other specific properties are needed, alternative materials such as alloy steel, carbon fiber, or composite materials may be more suitable, despite being more expensive. Therefore, when selecting materials for hydrogen storage, it is crucial to consider various important factors to ensure safety, reliability, and optimal performance according to project requirements. Consultation with experienced engineers or material experts is recommended to choose the appropriate material for your specific needs.