Ahmad Aminzadeh - University of Tehran (original) (raw)

Papers by Ahmad Aminzadeh

Artificial Intelligence-based optimization of Variable Blank Holder Force to reduce residual stress and improve formability; Experimental and statistical analysis

Many contributory factors can influence the quality of the deep drawing process, among which Blan... more Many contributory factors can influence the quality of the deep drawing process, among which Blank Holder Force (BHF) plays a decisive role. Therefore, controlling the BHF during the deep drawing process can bring many advantages and act as a deterrent against process failures, including tearing, wrinkling, and fatigue due to excessive residual stress and cyclic loads. Variable Blank Holder Force (VBHF), in which the BHF varies along the punch stroke, has recently been a popular method for improving sheet metal quality in the deep drawing process. In this study, VBHF was optimized to improve the formability of the process and reduce the residual stress using two different methods of Artificial Intelligence (AI) and Response Surface Method (RSM). The main purpose of this research is to introduce a new approach based on AI for VBHF optimization and compare the result of which with that of previous methods (Statistical methods). To reach this aim, BHFs in seven different stages of punc...

Applied Sciences

In an increasingly competitive industrial world, the need to adapt to any change at any time has ... more In an increasingly competitive industrial world, the need to adapt to any change at any time has become a major necessity for every industry to remain competitive and survive in their environments. Industries are undergoing rapid and perpetual changes on several levels. Indeed, the latter requires companies to be more reactive and involved in their policies of continuous improvement in order to satisfy their customers and maximize the quantity and quality of production, while keeping the cost of production as low as possible. Reducing downtime is one of the major objectives of these industries of the future. This paper aimed to apply machine learning algorithms on a TA-48 multistage centrifugal compressor for failure prediction and remaining useful life (RUL), i.e., to reduce system downtime using a predictive maintenance (PdM) approach through the adoption of Industry 4.0 approaches. To achieve our goal, we followed the methodology of the predictive maintenance workflow that allows...

Applied mechanics, Nov 16, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Predicting the forming limit diagram of the fine-grained AA 1050 sheet using GTN damage model with experimental verifications

Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture

In this research, forming limit diagram (FLD) of aluminum alloy 1050 (AA 1050) sheet produced by ... more In this research, forming limit diagram (FLD) of aluminum alloy 1050 (AA 1050) sheet produced by Accumulative Roll Bonding (ARB) is investigated numerically and experimentally. The Gurson-Tvergaard-Needleman (GTN) ductile damage model is used to predict sheet failure and obtain its FLD using numerical simulation in Abaqus/Explicit. Nucleation and growth of voids in the material during the deformation is the basic concept of the GTN damage model. This damage model has nine basic parameters that obtaining through experimental tests is time-consuming and costly, and in some cases, impossible. Thus, the present study tries to obtain the above parameters for fine-grained aluminum 1050 fabricated by ARB using the finite element method. Therefore, after considering each parameter’s interval, numerical simulation and the anti-inference method are used in the uniaxial tensile test to identify GTN parameters for the AA 1050 sheet using FEM. The optimum parameters of the GTN model are used in ...

Applied Mechanics

In this study, a novel approach for residual stress (RS) distribution on forged AA7175 is conside... more In this study, a novel approach for residual stress (RS) distribution on forged AA7175 is considered to replace and simplify the manufacturing process, based on the lean manufacturing concept. AA7175 alloy is a quench-sensitive material applied in the aeronautics industry, which is subjected to vibration and cyclic loads leading to fatigue failure. Generally, costly postprocessing operations, such as shot peening, are used to modify RS on the surfaces of parts. Considering the fact that this operation is usually performed manually and is costly, the industrial sectors have been searching for an alternative to simplify the process. Here, quenching and T74 aging are found to advantageously modify RS distribution by forming compressive RS on parts’ surface layers. The proposed heat treatment allows for the removal of the shot-peening process, helping to reduce the costs associated with the manufacturing process and to increase production quality.

A novel assembly process guidance using augmented reality for a standalone hybrid energy system

The International Journal of Advanced Manufacturing Technology

Smart Laser Welding: A Strategic Roadmap Toward Sustainable Manufacturing in Industry 4.0

Sustainable Manufacturing in Industry 4.0, 2023

Materials

Inspection methods, also known as non-destructive evaluation (NDE), is a process for inspecting m... more Inspection methods, also known as non-destructive evaluation (NDE), is a process for inspecting materials, products, and facilities to identify flaws, imperfections, and malfunctions without destruction or changing the integrity of materials, structures, and mechanisms. However, detecting those defects requires test conducting and results inferring, which is highly demanding in terms of analysis, performance, and time. New technologies are therefore needed to increase the efficiency, probability of detection, and interpretability of NDE methods to establish smart inspection. In this context, Artificial intelligence (AI), as a fundamental component of the Industry 4.0, is a well-suited tool to address downsides associated with the current NDE methods for analysis and interpretation of inspection results, where methods integrating AI into their inspection process become automated and are known as smart inspection methods. This article sheds a light on the conventional methods and the ...

A Novel Automated Approach for Geometric Reconstruction and Flexible Remanufacturing of Spur Gears Using Point Cloud Mapping Analysis

Computer-Aided Design and Applications

Quantum Beam Science

The benefits of laser welding include higher production values, deeper penetration, higher weldin... more The benefits of laser welding include higher production values, deeper penetration, higher welding speeds, adaptability, and higher power density. These characteristics make laser welding a superior process. Many industries are aware of the benefits of switching to lasers. For example, metal-joining is migrating to modern industrial laser technology due to improved yields, design flexibility, and energy efficiency. However, for an industrial process to be optimized for intelligent manufacturing in the era of Industry 4.0, it must be captured online using high-quality data. Laser welding of aluminum alloys presents a daunting challenge, mainly because aluminum is a less reliable material for welding than other commercial metals such as steel, primarily because of its physical properties: high thermal conductivity, high reflectivity, and low viscosity. The welding plates were fixed by a special welding fixture, to validate alignments and improve measurement accuracy, and a Computer-Ai...

Metals, 2021

In this article, the forming limit diagram (FLD) for aluminum 6061 sheets of thicknesses of 1 mm ... more In this article, the forming limit diagram (FLD) for aluminum 6061 sheets of thicknesses of 1 mm and 3 mm was determined numerically and experimentally, considering different punch velocities. The punch velocity was adjusted in the range of 20 mm/min to 200 mm/min during the Nakazima test. A finite element (FE) simulation was carried out by applying the Johnson–Cook material model into the ABAQUSTM FE software. In addition, a comparison between the simulation and the experimental results was made. It was observed that by increasing the punch velocity, the FLD also increased for both thicknesses, but the degree of the improvement was different. Based on these results, we found a good agreement between numerical and experimental analyses (about 10% error). Moreover, by increasing the punch velocity from 20 mm/min to 100 mm/min in 1 mm-thick specimens, the corresponding FLD increased by 3.8%, while for 3 mm-thick specimens, this increase was 5.2%; by increasing the punch velocity from ...

Arabian Journal of Geosciences, 2019

Water is an inherent component in coal masses. The presence of moisture has a significant impact ... more Water is an inherent component in coal masses. The presence of moisture has a significant impact on the mechanical properties of gas-bearing coal and plays a key role in the development of coal and gas outburst disaster. However, how moisture affects the mechanical behavior of gas-bearing coal is poorly understood. In this research, a series of triaxial compression and acoustic emission (AE) tests were performed on gas-bearing coal under different water treatment conditions. The results show that moisture reduces the change in surface energy of the coal by methane adsorption due to the predominance of water adsorption. Therefore, the influence of moisture is more prominent than that of methane and results in a reduction in strength and enhancement in the gas softening coefficient with increasing moisture content. Simultaneously, AE activity of gas-bearing coal is significantly inhibited by moisture, and two failure types can be determined based on the AE results around peak stress: a sudden rupture type for dry and low-water-bearing coal and a stable rupture type for water-saturated coal. Moreover, a meso-statistical damage model is proposed, which agrees well with the experimental results. An analysis indicates that the moisture in coal can reduce the surface energy and weaken the bonds among coal matrix particles, which not only changes the strength of gas-bearing coal but also restrains the energy release during failure; thus, moisture promotes the development of damage in gas-bearing coal.

Deep drawing is a forming process widely used in aerospace, military, automotive, and various ind... more Deep drawing is a forming process widely used in aerospace, military, automotive, and various industries. One of the essential useful parameters in the quality of deep-drawn products is Blank Holder Force (BHF). By Controlling BHF during the process, formability has been improved, reduced forming energy, and sheet thickness. Tearing is one of the most common and crucial defects in this process due to high radial stress in the cup's wall, resulting in many limitations in this field. In this process, the blank holder force plays an indispensable role in causing tearing. Therefore, controlling blank holder force during the process would be inevitable to avoid tearing or even wrinkling. This study aims to calculate the tearing limit with new criteria in analytical dominating plasticity Equations based on the slab Method. The St14 sheet with 1 mm thickness and 200 mm diameter is used in this study. The maximum blank holder force in each stage of punch stroke with new criteria based o...

A novel approach of residual stress prediction in ST-14/ST-44 laser welded blanks; mechanical characterization and experimental validation

Materials Letters, 2021

Abstract Sheet metal components capitalizing on the advantages of laser-welded blanks (LWBs) are ... more Abstract Sheet metal components capitalizing on the advantages of laser-welded blanks (LWBs) are widely used in automotive industries. In the current study, residual stresses are estimated in a deep drawing process of LWBs both experimentally (hole drilling) and numerically (using SIMUFACTTM and ABAQUSTM). This study aims at predicting residual stresses during laser welding and forming processes to improve the quality and service life of LWBs. Validating our proposed model on automobile parts presents promising results in which welding geometry and residual stress of LWBs are well estimated. These numerical and experimental stress analyses agree with a maximum error of 6%.

Comparison between laser beam and gas tungsten arc tailored welded blanks via deep drawing

Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 2020

This paper aims at analyzing the deformation behavior of tailor welded blanks (TWBs), manufacture... more This paper aims at analyzing the deformation behavior of tailor welded blanks (TWBs), manufactured by laser beam welding (LBW) and gas tungsten arc welding (GTAW), through the deep drawing process. Dissimilar and similar steels with different thicknesses were used in the production of tailor welded blanks. The Nd: YAG laser welding method with nitrogen (N2) as the shielding gas was used to join TWBs. The effects of some significant process factors, namely welding speed, blank holder forces (BHF), material properties of base metals, dry/lubricated condition and laser spot size was experimentally investigated on the weld line movement and drawing depth. Results indicated that using LBW with optimum parameters for the production of dissimilar TWBs caused the control of failure in the weaker base metal. Results showed that the sound welds were produced in similar TWBs with a thickness ratio of 2 when using GTAW, but the weld quality was poor when using LBW. Moreover, it is observed that...

Multi-objective topology optimization of deep drawing dissimilar tailor laser welded blanks; experimental and finite element investigation

Optics & Laser Technology, 2020

Abstract Laser welded blanks (LWBs) are semi-finished components typically manufacture by dissimi... more Abstract Laser welded blanks (LWBs) are semi-finished components typically manufacture by dissimilar materials, thicknesses, shapes, coatings, etc. After butt welding of the primary sheets, the product sheets are subjected to the sheet metal forming process. Formation of the heat-affected zones (HAZ) is typical in LWBs, which possess quite different mechanical properties than the base materials. Recently, laser beam technologies have been widely employed to weld different types of vehicles panels. In this study applying Nd:YAG laser welding, experimental and numerical investigations are carried out to evaluate the effects of process input factors on deep drawing process of LWBs. Laser beam power, welding speed, blank holder force (BHF), material properties, and friction coefficient are considered as process key input parameters. In addition, the laser welding and deep drawing processes were numerically simulated using Simufact Welding and Abaqus/Explicit software, Used the Simorgh supercomputer for heavy modeling calculations. Moreover, drawing depth, weld line movement, and energy absorption are taken into account as process main outputs or objective functions. Besides, using an advanced MATLAB code, multi objective optimization based on genetic algorithm is applied to determine the optimal design input parameters. It is observed that the critical stresses were taken place outside the weld zone and rupture due to high heat input of laser and metallurgical changes of the base metal occur in the pre-softening zone. In addition, the weld line displacement occurs as a result of plastic strain change of the weld joint that causes failure-prone zone creation as well as the adverse wrinkling. By considering weld line displacement and absorbed energy as multi-objective function, the optimal points is 1.15 mm and 0.21 KJ for weld line displacement and absorbed energy, respectively. Good agreement between the simulated and the experimental results revealed that the model would be appropriate for deep drawing of LWB process numerical simulation.

3D hardness profile mapping and geometrical defect prediction of laser-welded galvanized steel blanks using wobbling technology: an experimental investigation

The International Journal of Advanced Manufacturing Technology, 2022

A Novel Approach of Friction Stir Cladding of Aluminum on Carbon Steel Plate; Experimental Investigation and Material Characterization

Cladding is usually used to improve the material functionality (i.e. corrosion, wear, and oxidati... more Cladding is usually used to improve the material functionality (i.e. corrosion, wear, and oxidation) and to improve the mechanical and thermal properties of the components in different industries. In this study, a new cladding approach based on the friction stir processing was successfully employed on carbon steel plate with 6061-T6 Aluminum alloy. The mechanical and metallurgical properties of the cladding layer were examined at different process parameters. Metallurgical investigation of ST/Al interface was also evaluated using the Scanning electron microscope (SEM) and Optical microscope (OM). Two alloys were mixed uniformly together in the proper process conditions. Based on the results, the decrease of rotational speed from 1200 rpm to 800 rpm at a constant traverse speed of 15 mm/min, the cladding strength increased from 3.7 KN to 4.8 KN. At constant rotational speed of 800 rpm, with an increase in traverse speed from 15 mm/min to 35 mm/min, the cladding strength increased fro...

Experimental Study of Weld Line displacement and Drawing Depth in TWBs Sheets Manufactured by Laser beam and Friction Stir Welding

According to the fact that the FDM process has several input parameters that should be optimized ... more According to the fact that the FDM process has several input parameters that should be optimized toward a zero-defect manufacturing production. In this chapter, at first statistical analysis and mathematical methods used in the design of the experiment and optimizing printing parameters, which are used in FDM printing parameters are defined, and then they are reviewed, discussed and categorized. In this regard, the application of different methods such as statistical modelling, design of experiments (DOEs), Artificial Neural Networks (ANN), Genetic Algorithms (GA), and Hybrid approaches are discussed. In the next section, using the results of researches in this field, they are reviewed on a case-by-case basis and the optimal printing parameters with different conditions, materials and goals are introduced in FDM 3D printing.