Subjects: Mechanical Engineering >> Machine Tool submitted time 2024-05-14
Abstract： In-process detection of cutting forces, temperature, roughness, wear etc. during machining of titanium alloys are very important. The Finite element (FE) analysis plays an important role in monitoring and detection of machining responses. It offers a high accuracy in modeling of dry cutting processes and its performance in modeling of cryogenic machining process is a matter of interest. In this context, current investigation focuses on the dry turning and LN2/CO2 cooling assisted turning process of commonly used Ti6Al4V alloy. It is very useful material in the biomedical sector, and the simulation of cutting forces and cutting temperature via finite element method (FEM) has been performed. In addition, the simulation results are validated with experimental work. The results show that the deviations between FE modeling and experimental results for the cutting temperature are the average of 5.54%, 5.18% and 8.42% for the dry, LN2 and CO2 cooling conditions, respectively. On the other hand, the deviations from FE modeling and cutting force test results were 3.74%, 3.358%, and 3.03% under dry, LN2 and CO2 cooling conditions, respectively.
Subjects: Mechanical Engineering >> Machinofacture Technique and Equipment submitted time 2024-05-12
Munish Kumar Gupta
Hamza El Etri
Mehmet Erdi Korkmaz
Nimel Sworna Ross
Grzegorz M. Krolczyk
Józef Gawlik
Nafiz Yaşar
Danil Yu Pimenov
Abstract： Being easily fabricated, welded, biocompatible, having a high strength-to-weight ratio, withstanding comparatively high temperatures up to 800 °C and low modulus of elasticity make grade titanium and its alloys an important choice for automotive, biomedical and aerospace industries. In contempt of the different pleasant assets of Ti–6Al–4V alloy, the operation of this alloy is restricted especially when it comes to tribological and surface morphological characteristics. Enhancing these properties is important, for this purpose, a diversity of attempts and studies have been conducted. This paper mounts a review of morphological and tribological behaviors of titanium alloys including Ti–6Al–4V against different materials counting with carbide tools and other types of materials under dry and lubricated sliding conditions. The surface morphological, wear, and other properties have been discussed in this review article.
Subjects: Mechanical Engineering >> Machine Tool submitted time 2024-05-10
Grzegorz M. Krolczyk
Ça#1;grı Vakkas Yıldırım
Murat Sarikaya
Munish Kumar Gupta
Italo Tomaz
Danil Yu Pimenov
Mustafa Kunto#1;glu
Navneet Khanna
Abstract： Today, superalloys (also known as hard-to-cut materials) such as nickel, titanium and cobalt based cover a wide range of areas in engineering applications. At the same time, challenging material properties namely high strength and low thermal conductivity cause low quality in terms of cutting tool life and surface integrity of the machined part. It is important to improve the machinability of this type of materials by applying various methods in the perspective of sustainability. Therefore, current study presents surface integrity, tool wear characteristics and initiatives to improve them during the machining of superalloys. In this manner, it is outlined the surface integrity characteristics containing surface defects, surface roughness, microstructure alterations and mechanical properties. Also, tool wear mechanisms for example abrasive, adhesive, oxidation, diffusion and plastic deformation are investigated in the light of literature review. Finally, possible improvement options for tool wear and surface integrity depend on machining parameters, tool modifications, cooling methods and trade-off strategies are highlighted. The paper can be a guide for the researchers and manufacturers in the area of sustainable machining of hard-to-cut materials as explaining the latest trends and requirements.
Subjects: Mechanical Engineering >> Machinofacture Technique and Equipment submitted time 2024-05-10
Abstract： In this work, the sustainable machining approach is promoted by implementing the dry and minimum quantity lubrication (MQL) cooling conditions in the turning of duplex stainless steel. Initially, the turning experiments were performed under dry as well as MQL conditions and then, the influence of different positions of MQL nozzles on tribological and machining performance of 2205 duplex steel was investigated. The cutting parameters were kept fixed and the performance is evaluated in terms of surface roughness, micro-hardness, energy consumption, tool wear, machined surface microstructure and chips morphology. The results demonstrated that the highest average surface roughness values were obtained under dry conditions, with a value of 2.20 μm while MQL (flank + rake directions) produces the lowest surface roughness value of 1.55 μm with an improvement of 30%. Moreover, dual-jet MQL gives the lowest energy consumption (229 kJ) and tool wear (0.15 mm) with 23.67% and 52.38% enhancement, respectively.
Subjects: Mechanical Engineering >> Other Disciplines of Mechanical Engineering submitted time 2024-04-02
X Zhang
S. Mohammad Sajadi
Omid Malekahmadi
Z Li
Nidal H. Abu-Hamdeh
Muhyaddin J. H. Rawa
Meshari A. Al-Ebrahim
Aliakbar Karimipour
HPM Viet
Abstract： In this study, first, an orthopedic plate was 3D printed with Polylactic acid (PLA) and coated with polycaprolactone (PCL)/Akermanite (AKT) nano-fibers. The composition included 8 wt.% of PCL and 3 wt.% of nAKT, while diameter of the PCL/AKT nano-fibers was approximately 253 nm ± 33 nm. Thermomechanical properties such as pressure, three-point bending flexural, and thermal conductivity of coated and non-coated specimens were examined and compared. In the next step, the bioactivity of the coated samples was evaluated following a 28-day immersion in simulated body fluid (SBF). Further, scanning electron microscope (SEM) images were taken to assess morphology of nanofibers and apatite formation on samples. By adding PCL to PLA, the maximum pressure force is enhanced by 16.83%. Further by adding nAKT to PLA+PCL sample, the maximum pressure force is enhanced by 4.72%. Further, by adding PCL to PLA, the maximum bending flexural force is enhanced by 21.06%. Further by adding nAKT to PLA+PCL sample, the maximum bending flexural force is enhanced by 21.39%. The results of this study are used to improve modeling of the orthopedic plates.
Subjects: Mechanical Engineering >> Mechanical Design submitted time 2024-04-01
Abstract： Overstaffing production in underground coal mining is not convenient for daily management, and incomplete information of coal miners hinders the rescue process of firefighters during mine accidents. To address this safety sustainability issue, a novel face recognition method based on an improved multiscale neural network is proposed in this paper. A new depthwise seperable (DS)-inception block is designed and a joint supervised loss function based on center loss theory is developed to constructe a new multiscale model. The miniers can be recognized in the harsh underground environment during the life rescue. Experimental results show that the accuracy, recall and F1-score indexes of the proposed method for the miner face recognition in the underground mining environment are 97.26%, 94.17% and 95.42%, respectively. Transfer model with joint supervised loss can effectively improve the recognition accuracy by about 0.5~1.5%. In addition, the average recognition accuracy of the proposed face recognition method achieves to 91.34% and the miss detection rate is less than 5% in the dugout tunnel of coal mine.
Subjects: Mechanical Engineering >> Cutting Tool Technology submitted time 2024-03-31
Nikodem Wrobel
Michal Rejek
Jolanta Krolczyk
Mateusz Franka
Munish K. Gupta
Marcin Sliwinski
Grzegorz Krolczyk
Z. Li
Abstract： The present article describes a new and innovative method of producing an inseparable joint with the use of expansion jaws. The effect of jaw tool geometry on the reaction forces and ultimate strength of an inseparable joint formed on a prototype stand was analyzed. The results are also compared of joints produced by jaws with single movement method and with complex movement method. The tool responds with bending and pressing one part into the other, which results in their permanent connection. In the tests, differentiation was introduced with regard to the height of the applied force to the collar of the connection pipe. A novelty is also a solution based on a complex, parameterized trajectory of the stamp movement consisting of horizontal and vertical displacements. This paper presents the tests of the joints formed at the stand. The new approach described in this article has resulted in a joint strength increase of approximately 30% using the innovative complex jaw movement of the biaxial clinching process. A joint tensile strength close to 1000 N was achieved.
Subjects: Mechanical Engineering >> Mechanical Design submitted time 2024-03-31
Abstract： The bottom pivot is a vital support device in the miter gate but often subject to poor lubrication and wear failures. Calculating the hydrodynamic lubrication characteristics of the bottom pivot is a complex three-dimensional (3D) problem, and most of existing models adopt simplified assumptions to reduce the calculation difficulty. To solve this issue, this work develops a 3D model to calculate the hydrodynamic lubrication characteristics of the miter gate bottom pivot. The finite difference method is used to solve the oil film thickness and pressure distribution based on the spherical coordinates Reynolds equation. The component forces in three directions are calculated from the pressure distribution and compared with the theoretical values to generate the calculation difference. Then, the genetic algorithm (GA) is used to minimize the difference to determine the optimal initial parameters for the 3D model. The analysis results show that the calculation accuracy can be significantly improved by using the optimal initial model parameters. When our initial pressure is 5.64MPa, the results meet the engineering accuracy requirements.
Subjects: Mechanical Engineering >> Machinofacture Technique and Equipment submitted time 2024-03-28
Abstract： The heat transfer mechanism and temperature distribution in laser welding applications have a great impact on the quality of the weld bead geometry, mechanical properties and the resultant microstructure characterizations of the welding process. In this study, the effects of pulsed laser welding parameters including the frequency and pulse width on the melt velocity field and temperature distribution in dissimilar laser welding of stainless steel 420 (S.S 420) and stainless steel 304 (S.S 304) was investigated. A comprehensive comparison was conducted through the numerical simulation and artificial neural network (ANN). The results of numerical simulation indicated that buoyancy force and Marangoni stress are the most important factors in the formation of the flow of liquid metal. Also, increasing the pulse width from 8 to 12 ms due to increasing the pulse energy, the temperature in the center of the melt pool increased about 250 °C. This leads to increasing the convective heat transfer in the molten pool and heat affected zone (HAZ). The temperature difference at a distance of 1 mm from the beam center at both metals at a frequency of 15 and 20 Hz is bout 58 and 75 °C, respectively. Furthermore, reducing the frequency to 5 Hz, due to diminishment of thermal energy absorption time, has clearly decreased the weld penetration depth in the workpiece. According to the ANN results, increasing both pulse duration and frequency has the significant effect on increasing melting ratio from 0.4 to 0.8 compared to the other input parameters. The ANN results confirmed that under the same input conditions, because of the differences in thermal conductivity coefficient, absorption coefficient and melting point of the two pieces, S.S 304 has experienced higher temperatures about 10% more than S.S 420. Also, among the 13 back propagation learning algorithms, the Bayesian regularization algorithm had the best performance. Among the number of different neurons in the hidden layer, comparison was performed to prevent network overfitting. The maximum relative error of network output data and target data for S.S 304 and S.S 420 temperatures and melting ratio were 7.297, 10.16 and 11.33%, respectively.
Subjects: Mechanical Engineering >> Other Disciplines of Mechanical Engineering submitted time 2024-03-28
Darius Andriukaitis
Zhixiong Li
Xiaofei Wen
Mustafa Inc
Linxiang Li
Hadi Bagheri
S. Mohammad Sajadi
Chunsheng Yang
Abstract： Increasing the transfer (HT) coefficient used in thermal industries is very important. Various methods are used to improve the efficiency of thermal heat HT so that maximum HT takes place in a smaller space. Ethylene glycol (EG) is generally used as an agent for convective HT. EG obtains energy from a hot source and discharges it to the required location. At present, the most consumption of EG is to produce engine cooling fluid. In the upcoming research, the TB of EG fluid in two-dimensional microchannels (MCs) has been investigated using molecular dynamics (MD) simulations, and the effect of variables such as MC dimensions and MC wall temperature (Temp) on the TB of the simulated fluid has been investigated. The results revealed that by increasing the Temp difference of the MC wall from 10 to 50 K, the maximum temperature (Max-Temp) and velocity (Max-Vel) of the target sample increased to 640.94 K and 0.024 Å/ps. It can be concluded that the increase in the cross-sectional area and the wall Temp difference leads to an increase in the HT rate in the MC.
Subjects: Mechanical Engineering >> Mechanical Manufacture and Automation submitted time 2024-01-07
Abstract： In recent years, with the rapid development of the chemical industry and information combination, the data produced in the chemical refining system presents explosive growth. Alarm system is a kind of transmitting equipment abnormal state information to the operator of the system, but if the design is not reasonable, the equipment under abnormal state process may produce a large number of alarm and alarm saturation phenomenon, the serious influence the operator's information processing ability, thus increasing the probability of all kinds of industrial accidents. Therefore, how to mine useful information from the massive alarm logs is very important, and use the mined information to give positive guidance to the complex refining process. Deep learning is a method that can automatically learn and extract features from data. It does not require manual construction of complex and accurate physical and mathematical models, so it has been widely applied and paid attention to in the field of data prediction and classification.
Peer Review Status:
Awaiting Review
Subjects: Mechanical Engineering >> Mechanical Manufacture and Automation submitted time 2022-10-21
Abstract： With growing interest in Laser Additive Manufacturing (LAM) of High-entropy alloys (HEAs) during most recent years, compositional elements design and process strategies innovation are primary methods to overcome undesirable microstructures and defects. Here we propose a new approach, a novel real-time laser shock modulation of melt pool (LSMMP) to obtain melt pool modifications for yielding HEAs with desired characteristics. LSMMP utilizes a pulsed laser shocking a liquid melt pool caused by a continuous wave laser, enabling non-destructive and real-time modulations for high-performance HEAs. The numerical simulation reveals the convection mechanism of the melt pool in the LSMMP process, and the intervention of the pulsed laser promotes melt pool flow type to convert the Marangoni effect into a multi-convective ring, which accelerates melt pool flow and inhibits columnar crystal growth. Experimental results show the evolution law of the microstructure in the LSMMP process. The microstructure of CrFeCoNi HEAs undergoes a Columnar-Equiaxed Transition (CET), and higher hardness is obtained. Laser shock is demonstrated to be an effective in-situ modulative tool for controlled additive manufacturing.
Subjects: Mechanical Engineering >> Mechanical Manufacture and Automation submitted time 2022-09-26 Cooperative journals: 《桂林电子科技大学学报》
Abstract：
To test the rationality of the power system for a fuel cell commercial vehicle, the models of energy source (including fuel cell stack and battery pack), electric motor system (including electric motor and its controller) and driveline are built in Matlab. A global optimization energy management strategy based on dynamic programing is adopt to analysis the vehicle’s fuel economy with the European typical drive cycle under three load modes (including no-load, half-load and fullload). Simulation results show that the energy source employed satisfy the vehicle’s power requirements at the selected drive cycle, while with the increase of on-board load, the terminal SOC of battery gradually deviates from the initial value, which will limit the commercial vehicle’s dynamic performance in the long term cycles with a large on-board load. Verification results for the vehicle point that great power on-board fuel cell stack should be considered in the following research and vehicle verification.
Subjects: Mechanical Engineering >> Mechanical Manufacture and Automation submitted time 2022-09-26 Cooperative journals: 《桂林电子科技大学学报》
Abstract： Aiming at the problem of low efficiency caused by complex and redundant calculation of robot dynamics model, a
programmed modeling method is proposed. Taking the Stanford Arm with six degrees of freedom as an example, the dynamic
model based on Lagrangian equation is established by using this method. According to the core idea of "forward analysis,
reverse output", the recursive process of the model is analyzed emphatically. On the basis of verifying the correctness of
the model, the indexes such as the dimensions and running time of the Stanford Arm model based on the PMM and the conventional
Lagrange equation without the use of the PMM are compared. The results show that relative to the conventional
Lagrange method, the complexity of the model established by PMM is reduced by 67.6%, and the computational efficiency
is increased by 66.3%. Stanford Arm is a complete constrained system. PMM is extended to underactuated nonholonomic
constrained systems, numerical simulation and physical prototype experiment analysis are carried out by using partial feedback
linearization control algorithm which is closely related to the model, it’s reliability and effectiveness of the programmed
modeling method are verified, which provides a modeling method with higher efficiency and better versatility for different
types of robots.
Subjects: Mechanical Engineering >> Machinofacture Technique and Equipment submitted time 2022-08-24
Abstract： This paper combines the relevant policies, routes and requirements for improving the employment and entrepreneurship ability of workers and improving the quality of skills training and accelerating the training of knowledge-based, skilled, and innovative high-skilled Labor constructor, and puts forward the suggestions and methods of digitization transformation for the training of CNC machine tool installation and maintenance technicians and senior technicians from several aspects, such as task analysis, method research, ability training, technical connotation analysis, training problem solving, teaching implementation steps and keys.
Peer Review Status:Awaiting Review
Subjects: Mechanical Engineering >> Mechanical Manufacture and Automation submitted time 2022-05-31
Abstract：
With growing interest in Laser Additive Manufacturing (LAM) of High-entropy alloys (HEAs) during most recent years, the design of compositional elements and process strategies are primary methods to overcome undesirable microstructures and defects. Here we propose a new approach, a novel real-time Laser Shocking of Melt Pool (LSMP), to obtain melt pool modifications for yielding HEAs with desired characteristics. LSMP utilizes a pulsed laser shocking a liquid melt pool caused by a continuous wave laser, enabling non-destructive and real-time modulations for high-performance HEAs. The numerical simulation reveals the convection mechanism of the melt pool in the LSMP process, and the intervention of the pulsed laser promotes melt pool flow type to convert the Marangoni effect into a multi-convective ring, which accelerates melt pool flow and inhibits columnar crystal growth. Experimental results show the evolution law of the microstructure in the LSMP process. The microstructure of CrFeCoNi HEAs undergoes a Columnar-Equiaxed Transition (CET), and higher hardness is obtained. Laser shock is demonstrated to be an effective in-situ modulative tool for controlled additive manufacturing.
Peer Review Status:Awaiting Review
Subjects: Mechanical Engineering >> Machinofacture Technique and Equipment submitted time 2022-05-25 Cooperative journals: 《桂林电子科技大学学报》
Abstract：在电子封装领域中,所用的无铅钎料主要是二元或者三元Sn基共晶或近共晶合金,其基体相为富Sn相。为得到富Sn相的力学性能及应力-应变关系,由纳米压痕试验测试获得了富Sn相的弹性模量与硬度,并得到载荷-位移曲线。采用有限元反演分析的方法确定了富Sn相的特征应力和特征应变,并由量纲函数确定应变强化指数。将特征应力和特征应变强化指数等参数代入幂强化模型中,计算得到富Sn相的屈服强度为31.51 MPa,并最终确定富Sn相的应力-应变关系函数表达式。
Subjects: Mechanical Engineering >> Other Disciplines of Mechanical Engineering Subjects: Computer Science >> Computer Software submitted time 2022-02-16
Abstract：
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Peer Review Status:Awaiting Review
Subjects: Electronics and Communication Technology >> Information Processing Subjects: Engineering and technical science >> Engineering General Technology Subjects: Mechanical Engineering >> Other Disciplines of Mechanical Engineering submitted time 2022-02-08
Abstract：The spectral leakage (SL) from windowing and the picket fence effect (PEF) from discretization have been among the standard contents in textbooks for many decades. The SL and PEF would cause the distortions in amplitude, frequency, and phase of signals, which have always been of concern, and attempts have been made to solve them. This paper proposes two novel decomposition theorems that can totally eliminate the SL and PEF, they could broaden the knowledge of signal processing. First, two generalized eigenvalue equations are constructed for multifrequency discrete real signals and complex signals. The two decomposition theorems are then proved. On these bases, exact decomposition methods for real and complex signals are proposed. For a noise-free multifrequency real signal with m sinusoidal components, the frequency, amplitude, and phase of each component can be exactly calculated by using just 4m1 discrete values and its second-order derivatives. For a multifrequency complex signal, only 2m1 discrete values and its first-order derivatives are needed. The numerical experiments show that the proposed methods have very high resolution, and the sampling rate does not necessarily obey the Nyquist sampling theorem. With noisy signals, the proposed methods have extraordinary accuracy.
Peer Review Status:Awaiting Review
Subjects: Mechanical Engineering >> Mechanical Design submitted time 2021-11-17
Abstract： The biomimetic design provides an adequate solution to achieve an excellent design. However, the prototype space for biomimetic design is relatively large, and it becomes more and more challenging to find the required biological prototypes quickly and efficiently. In order to improve the design efficiency and enrich the means of biomimetic innovation, this paper proposes a biological knowledge-enabled bidirectional encoder representation from transformers (BERT) model to assist biomimetic design, namely BioDesign. We extract the biological strategies, functions and extract dimensional information from the Asknature as the data source. The linguistic expression model-BERT was used to recommend biomimetic strategies or functions combined with the biological strategies data. Finally, we take the biomimetic erosion wear resistant design of the valve core as an example and use the proposed BioDesign model to recommend biomimetic inspired functions. According to the recommended content of the BioDesign model, we obtained the erosion wear resistance strategies and designed the biomimetic structure. The erosion wear experiment proved the feasibility and effectiveness of the proposed method.
Peer Review Status:Awaiting Review
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