bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of microalloying on the sheared edge ductility of ferritic steels
Authors: Hannula J. , Kaijalainen A. , Porter D. , Kesti V. , Kömi J.
Published: November 2019

Sheared edge ductility plays a critical role in many automotive and structural applications. The effect of microalloying elements on the microstructure, mechanical properties, sheared edge quality and hole expansion properties of six thermomechanically laboratory hot rolled and coiled, approximately 4 mm thick, precipitation hardened ferritic steels have been investigated. The studied V-microalloyed steels had low carbon contents, 0.05 and 0.09 wt.%, and, in some cases, microalloying additions of either Nb or Nb+Ti. Yield strengths were in the range 500 MPa to 750 MPa and hardness values between 176 and 260 HV10 depending on the carbon content and level of precipitation strengthening. Detailed microstructural analysis using laser scanning confocal microscopy (LCSM), FESEM and FESEM-EBSD revealed that all the steels consisted of mainly single-phase ferrite. FESEM analysis revealed the presence of relatively coarse precipitates at grain boundaries and inside some of the ferrite grains, but the number density of visible precipitates varied greatly between grains. The addition of Nb or Nb+Ti reduced the ferrite grain size, especially the size of the largest grains as defined by the 90th percentile in the cumulative grain area distribution (d90%). Mean hole expansion (HE) ratios varied from 39 % to 76 % with the highest values associated with the lowest carbon contents. Despite raising the strength, microalloying with Nb or Nb+Ti had little if any detrimental effect on HE ratios compared to the V-microalloyed variants without Nb or Ti, presumably as a result of the grain refinement. Titanium nitrides acted as void nucleation sites close to the sheared edge. Microalloying with Nb and Nb+Ti led to a decrease in the depth of the shear affected zone (SAZ) and a smaller difference in hardness between the base material and the SAZ.
Novel roll stand for flexible profile bending
Authors: Martschin J. , Meya R. , Löbbe C. , Tekkaya A. E.
Published: November 2019

A new method and roll stand for the manufacturing of structural profiles with tailored dimensions and properties based on the combination of rolling and profile bending is developed. Through this merged process the outer contour of a semi-finished product is shaped by a set of driven flexible and rigid rollers. The profile inner side is supported by an adjustable mandrel, so that an arbitrary variation of the cross-section along the profile can be achieved. Additionally, a moveable guiding roll facilitates the bending of the product. Conventionally, the manufacturing of load-optimized bent profiles requires a sequence of operations, whereas the novel method enables the manufacturing of those components in one process step. This leads to a reduction in tooling cost and setup time. Hence, the production of lightweight structures in small batch sizes is facilitated. In this contribution, the new forming method and the design of the developed roll stand are presented alongside with an investigation of the effects of stress superposition on bending stresses during combined bending and rolling as well as the possible processes applications.
Parameter identification of 3D yield functions based on a virtual material testing procedure
Authors: Butz A , Wessel A , Pagenkopf J , Helm D
Published: November 2019

The parameter identification of anisotropic 3D yield functions for sheet metals based on experimental data is very difficult, because material properties associated to the out-of-plane stress states cannot be directly measured. An alternative and promising approach for identifying parameters of anisotropic yield models, and particularly for 3D yield models, is the concept of virtual testing. Within the presented work, a full-field microstructure simulation framework based on a crystal plasticity (CP) model is used to determine macroscopic mechanical properties of a ferritic deep drawing steel DX56 within 3D stress space. The results are utilized to identify the parameter of anisotropic 2D and 3D yield models according to Hill [1] and Barlat [2, 3].
Pressure and sliding velocity dependent surface asperity based friction model: Application to springback simulation
Authors: Lee K J , Lee M G
Published: November 2019

For accurate predictions of the formability and springback in the finite element sheet forming simulations, significant advances have been achieved in constitutive modeling that captures complex deformations occurring in the sheet forming process. However, friction behavior has been still modeled and implemented as a simple way though it is one of critical factors for accurate numerical simulations. For instance, sheet metal forming simulations often employ the Coulomb friction law with a constant friction coefficient, but it is known to be a function of other factors such as contact pressure, sliding rate and other surface quality. In this study, the microscopic surface asperity based friction model originally proposed by Westeneng [1], as one of microscale level friction models, was revisited by using additional contact assumptions. In particular, the model added the strain rate effect to the existing contact pressure dependent model in order to include the effect of both contact pressure and sliding velocity during sheet forming process. The calculated contact friction coefficient was compared to that by the measured for dual-phase 780 steel sheet under different pressure and sliding velocity. Moreover, the predicted friction model was employed in the simulation of U-draw bending springback by using a user friction subroutine, which was evaluated by the comparison of experimentally measured springback profile
Parameter Measurement and Conductive Heating During Press Hardening by Hot Metal Gas Forming
Authors: Bach M , Degenkolb L , Reuther F , Psyk V , Mauermann R , Werner M
Published: November 2019

Press hardening of steels for the production of car body components is very common. The reason for this is that the process allows the use of blanks with low wall thickness and the production of ultra-high strength components with complex geometries. The Hot Metal Gas Forming (HMGF) process for closed profiles combines the advantages of hydroforming, such as increased rigidity, functional integration or elimination of joining operations, with those of press hardening. In this paper results of continuous tests with actively cooled tools are presented in combination with temperature and displacement measurement. Furthermore, test results for HMGF with tool integrated conductive heating are demonstrated. Tests were done with tube material PHS1800 by SSAB, part temperatures over the Point of austenitisation and maximum internal pressure of 70 MPa. Thermocouples recorded the heat distribution in the tools. Other measured and recorded variables were the displacement of the component wall while forming under increasing internal pressure by a tactile displacement sensor and simultaneous temperature of its surface with a thermal sensor head. For the first time, information on pressure, the corresponding deformation stage and temperature profile could be documented during an entire forming step. A close to series production geometry DP4 was used to investigate the tool-integrated conductive heating of components.
Feedback control of laser forming using flattening simulations for error determination
Authors: Thomsen Anders Noel , Endelt Benny , Kristiansen Morten
Published: November 2019

Laser forming is a non-contact forming method. By control of different process parameters, different forming mechanisms can be achieved. The forming mechanisms allows for bending, compression and buckling. Process control to ensure correct combination and usage of each forming mechanism is still an open issue. Present work is an attempt to implement a feedback control loop using measurements of the current shape between laser scan pass. This work presents an initial case study used to evaluate a feedback control loop. A flattening model is used to determine the difference in strains between a target shape and the current shape. The current shape is updated between laser scan paths. The case study examines different shapes including the dome, saddle and v-bend shapes. By examining different shapes that require different forming mechanisms, this work takes steps toward formulating process design principles for use in feedback control of laser forming. The results show decent agreement with the target shape and the formed shape for the v-bend. As the cases increase in complexity, requiring a combination of forming mechanisms, the disagreement increases. The analysis of the process indicates that the boundary conditions of the flattening model and the design of the controller could be improved to reduce tolerances.
Strain Rate and Temperature Dependent Plastic Response of AA7075 during Hot Forming
Authors: Pandya K. S. , Roth C. C. , Mohr D.
Published: November 2019

High strength 7xxx series aluminum alloys are being increasingly considered for automotive applications due to their superior specific strength compared to 6xxx series alloys. Complex structural components made from 7xxx series alloys need to be manufactured through warm forming or hot stamping due to their low ductility at room temperature. For hot stamping, the AA7075 blanks are heat treated to above 480°C, yielding a supersaturated solid solution, corresponding to a W temper state. The preheated blanks are then simultaneously formed and rapidly quenched using cooled dies. The entire forming process takes place in the W temper condition. The stamped parts are further subject to an artificial aging heat treatment to achieve the desired temper through precipitation hardening. Therefore, understanding the strain rate and temperature dependent plasticity behavior of AA7075-W is critical to establish optimum design parameters for the hot stamping process. The present work is concerned with the strain rate and temperature dependent plastic response of AA7075 in the W temper state. In particular, the results from a comprehensive experimental program on uniaxial tension specimens are presented. High temperature experiments are carried out at strain rates ranging from 0.001-2/s in a universal testing machine. An induction heating system with infrared high speed imaging is used to span the entire temperature range from 180°C to 480°C, over the full range of strain rates considered. Based on the experimental results, a candidate plasticity model with an empirical mixed Swift-Voce hardening law and a Johnson-Cook type strain rate and temperature dependence is calibrated.
Towards neural network models for describing the large deformation behavior of sheet metal
Authors: Gorji Maysam B. , Mohr Dirk
Published: November 2019

Neural networks provide a potentially viable alternative to a differential equation based constitutive models. Here, a neural network model is developed to describe the large deformation response of a Levy-von Mises sheet material with isotropic strain hardening. Using a conventional return-mapping scheme, virtual experiments are performed to generate stress-strain data for random monotonic biaxial loading paths (up to strains of 0.2). Subsequently, a basic feedforward neural network model is trained and validated using the results from virtual experiments. The results for a shallow network with only two hidden layers show remarkably good agreement with all experimental data. The identified neural network model is implemented into a user material subroutine and used in basic structural simulations such as uniaxial tensile and notched tension experiments. In addition to demonstrating the potential of neural networks for modeling the rate-independent plasticity of metals, their application to more complex problems involving strain-rate and temperature effects is discussed.
Friction modelling in sheet metal forming simulations for aluminium body parts at Daimler AG
Authors: Bolay C. , Essig P. , Kaminsky C. , Hol J. , Naegele P. , Schmidt R.
Published: November 2019

Tribology plays a key role in the production of high-quality car body parts. In forming simulations, often a constant value for the friction coefficient is used, which limits the overall simulation accuracy. In reality, friction depends on the pressure distribution, forming velocity, interface temperature, plastic strain, type/amount of lubrication and the surface topography of both the sheet and the tooling. The simulation accuracy, and therefore the prediction of the formability of complex geometries, can be improved significantly by taking all these parameters into account. This paper presents a selection of results for 2 aluminium cases: 1 scientific part conducted at the IFU Stuttgart and 1 complex body part from Daimler AG. Simulation results have been validated by experimental results to show the influence of friction on e.g. part quality, draw-in and spring-back. Results show that friction modelling becomes increasingly important in the stamping process of aluminium parts, and that the overall simulation accuracy increases when accounting for the actual tribological conditions in stamping.
Die Quench Process Sensitivity of AA7050
Authors: Boulis R. , DiCecco S. , Worswick M.J.
Published: November 2019

The current work investigates the sensitivity of AA7050 aluminum alloy sheet to the thermal cycle involved in the die quenching (DQ) process. This entailed the variation of three key parameters in the thermal cycle, namely solutionizing time, transfer time and quench rate, considering both water quenching (WQ) and die quenching (DQ) at various die pressures. Following a lab-grade T6 heat treatment, Vickers hardness (HV-1000) measurements of all test conditions and tensile testing on a reduced number of test conditions were completed. The results showed only limited sensitivity to solutionizing time for the range of conditions tested. Longer transfer times and slower cooling rates both negatively affected final hardness properties, with up to 4% reduction in final hardness relative to the water-quenched T6 condition. Higher cooling rates during die-quenching produced statistically similar final tensile properties to those achieved from water quenching, following a T6 heat-treatment; while slower cooling rates resulted in significant reductions in tensile strength and uniform elongation. Limiting dome height testing of a 101.6 mm dome sample under die-quench conditions produced a major true limit strain of 0.42. The die-quench limit strain compared favourably against the limit strains of the same geometry in the T6 condition at room temperature and 150 °C (isothermal), which were 0.12 and 0.18, respectively.
Prediction of forming limit diagrams using machine learning
Authors: Chheda Amar M , Nazro Louis , Sen Fatih G , Hegadekatte Vishwanath
Published: November 2019

Measuring forming limit diagrams (FLDs) is a time consuming and expensive process. Data-driven and artificial intelligence approaches have been used to facilitate finding relationships between alloy composition, and manufacturing processing conditions with mechanical properties of materials. Machine learning (ML) methods are a promising route to predict FLD of aluminium alloys that are increasingly used in automotive structural applications. In the present work, we developed a machine learning (ML) based tool to establish the relationships between alloy composition / thermomechanical processing route to the material’s FLD, which is a measure of formability. Measured FLDs of various 5XXX and 6XXX aluminium alloys along with their chemical composition and thermomechanical processing parameters like homogenization, hot and cold rolling parameters etc. and the respective mechanical properties like n and r values were manually curated and stored in a database. A two-stage ML model was trained on this database. In the first stage, the minimum and maximum points of the minor strain were predicted using a feature set incorporating chemical composition, thermomechanical processing parameters, and n and r values using support vector regression (SVR). In the second stage, the predicted minor strain in the first stage was used as input in addition to the same feature set to predict the major strain using gradient boost regression (GBR). The trained ML model successfully predicted FLDs with R2 value above 0.93. To study the impact of the difference between a predicted and a measured FLD on stamping simulation results, finite element simulations of a cross die were performed. The difference in draw depth of the cross-die using the predicted FLD and the measured FLD was between 5 to 10%. The current results show that ML can be a viable way for predicting FLDs.
Simulation of the optimal control of a reagent supply in the in-situ uranium leaching process
Authors: Sadykov M P
Published: November 2019

This article develops an optimization task model for a physicochemical process that takes place in a mineral-bearing formation at the in-situ leaching of mineral. As a result of research, a certain hydrodynamic pressure and velocity field are obtained in a reservoir under the action network of wells, distributive reagent concentrations, mineral in a solid and liquid phase. Furthermore, according to this technique, the intensity-reagent impacts are studied on an extraction degree and mineral extraction time.
The neural networks application in predicting the geometrical parameters of coatings formed on a steel substrate by laser alloying
Authors: Ulakhanov N , Mishigdorzhiyn U
Published: November 2019

A mathematical model for predicting the geometric parameters of boron and aluminum-based coatings formed on a steel substrate by laser alloying is presented in the work. The model combines the principles of the theory of experiment planning with an artificial neural network (ANN) apparatus. Coatings were formed by means of laser heating of the steel surface with a pre-applied treatment paste. The ANN was built, trained and tested for the prediction of the width and depth of the molten bath on a steel substrate. The prediction results of the obtained neural network were compared with the corresponding linear models. The efficiency of the considered approach and the possibility of its application for predicting the values of laser treatment of steel parts of machines subjected to surface hardening are shown. The presented approach allows to use one mathematical model for predicting several parameters, thereby reducing the number of experiments.
Modeling and optimization of the processes of turbulence
Authors: Lvovich I Ya , Lvovich Ya I , Preobrazhenskiy A P , Choporov O N
Published: November 2019

In this paper the problem associated with the modeling and simulation of turbulent flows is considered. Turbulent flows are quite common and a complete theory is not built for them at the moment. Among the models that are based on the subgrid scale, the model proposed by Smagorinsky was chosen. On the basis of the created subsystem in the form of a cross-platform dynamic library for modeling turbulent media, the simulation of water flow around a circular obstacle was carried out. The simulation results are presented. Suggestions are given for the optimization procedure, with variations in the implementation of the considered system of medium motion.
Application of a discrete model of fatigue defect growth for assessment of the safe operation life of the main pipeline section with a corrosion defect
Authors: Vansovich K , Aistov I , Nakhlestkin A
Published: November 2019

The article proposes a model of fatigue defect growth obtained on the basis of the analysis of the three-dimensional stress state at the apex of the corrosion defect. To study the stress-strain state the actual operational loads of the pipeline were simulated by the finite element method. The scientific novelty of the study is that when developing a model of fatigue defect growth, it is assumed that the growth of the defect, which develops by the opening fracture mode, is controlled only by normal stresses. In one loading cycle, the intensity of the fracture process is determined by both the maximum tensile stresses during the loading period and the maximum compressive stresses during the unloading period. Based on the assumptions made, it has been established that the growth rate of fatigue defects of corrosion origin depends on the magnitude of the coefficient of the average stresses change ahead of the crack front during full loading cycle.
Stretch elasticity and garment pressure of shaping-underwear fabric
Authors: Gong Yun-Qi , Mei Shun-Qi
Published: November 2019

In recent years, the relationship between corsets and human health has been widely concerned. In order to explore the relationship between body shaping fabric and garment pressure, this paper starts from the reasons for the formation of body-dressing clothes, discusses the comfort range of human body wear and summarizes the principles, advantages and disadvantages of various methods of testing body-dressing clothes. At the same time, five elastic fabrics are selected to test their tensile properties. The garment pressures produced by the human calf diameter of 9 cm are also tested. The relationship between the tensile properties of the fabric and the garment pressure is analyzed, which lays the foundation for designing the intelligent corset that can meet the health requirements of people and realize the shaping of the body.
Synthesis and antimicrobical activity of composite oxides nanoparticles based on ZnO
Authors: Kondranova A M , Lozhkomoev A S , Kazantsev S O , Pervikov A V
Published: November 2019

It should be noted that zinc oxide nanoparticles have increased antibacterial activity. ZnO/Me composite nanoparticles have a more pronounced antimicrobial effect in comparison with monometallic nanoparticles obtained by similar conditions. In present work ZnO/Ag and ZnO/CuO composite nanoparticles were obtained by the electrical explosion of Zn and Cu or Zn and Ag wires in oxygen containing atmosphere. Composite nanoparticles were characterized by transmission electron microscopy, XRD analysis and micro electrophoresis. Antibacterial activity of composite nanoparticles against Gram-positive E.coli and Gram-negative MRSA was studied. The as-synthesized nanoparticles demonstrated excellent bactericidal effect due to their unique properties including not only components additive effect but also synergetic one.
Mathematical modelling of the process of melting alloys of the Si-Cr-Ni-Fe system in the iron-carbon melt
Authors: Zayakin O V , Renev D S , Zhuchkov V I , Lozovaya E Yu
Published: November 2019

The process of melting of the Si-Cr-Ni-Fe ferroalloys in the iron-carbon melt under static conditions was studied using the method of mathematical modelling. It was found that the melting process takes place in three stages. The effect of silicon concentration and the initial size of a piece of alloy on the duration of each stage of alloy melting is revealed. It was shown that an increase in the silicon content from 6 to 40 % in the complex ferroalloy of the 50 mm fraction containing ~ 27 % Cr and ~ 12 % Ni leads to a decrease in the total melting time of the alloys from 67 to 30 seconds at the iron-carbon melt temperature of 1600 ºC.
Analysis of the possibility of using Cu-Au nanoclusters as bits in phase charge memory devices
Authors: Bashkova D A , Gafner Yu Ya , Zamulin I S , Kuznetsov M F
Published: November 2019

This work analyses the potential of using copper-gold nanoalloy as a material for phase charge memory cells. For this purpose, smooth cooling of the melt of Cu-Au nanoclusters of 2.0 – 8.0 nm diameter was simulated with the molecular dynamics method, based on the modified tight-binding potential (TB-SMA). Particles of different chemical compositions were investigated. The gold content in the alloy varied from 10 to 90 percent. The authors also explored the influence of the cooling intensity on the character of the formed substructures. To reach the goal, the values of the heat removal rate were varied. As a result, nanoclusters of compositions Cu90Au10 and Cu10Au90 were found in a range of particles. Some parameters were selected for them, at which the stable development of amorphous and crystalline structures is possible.
Definition of preferable thickness of metal cylindrical panels with mild camber based on post-buckling behaviour due to compression
Authors: Mitrofanov O V
Published: November 2019

Engineer design methodology for metal cylindrical panels with mild camber with post-buckling behavior accepted in case of compression above limit level is suggested. Method is based on geometrically non-linear task analytic solution and is reduced to solution of non-linear equation in panel thickness with limit stress being reached with post-buckling behavior of rigidly supported panel taking into account initial deflection.
Post-buckling behaviour estimation of thin cylindrical composite shells of non-symmetrical structure in case of compression
Authors: Mitrofanov O V
Published: November 2019

The paper deals with the result of analytic solution of the geometrically non-linear task for composite thin-walled cylindrical shell post-buckling behavior in case of axial compression by using Bubnov-Galerkin method. Initial correlations take into account composite structure non-symmetry.
Design of cylindrical composite panels with mild camber for biaxial compression taking into account geometrical non-linearity with uniform heating and rigid support
Authors: Mitrofanov O V , Klesareva M V
Published: November 2019

Based on geometrically non-linear task analytic solution for cylindrical composite panel with mild camber method of best possible design for post-buckling state with biaxial compression is suggested. Uniform heating and panel all-boundary rigid support are taken into account in basic correlations.
On an optimization method of chemical reactors
Authors: Burlakov I D , Buldaev A S
Published: November 2019

The class of model problems of optimal process control of chemical reactors is considered. A new method of constructing successive approximations to the optimal problem solution is proposed, based on the implementation of the constructed conditions for improving control in the form of fixed-point problems. This form allows to apply and modify the theory and methods of searching for fixed points to optimize control. A comparative analysis of the effectiveness of the proposed optimization method with well-known computational algorithms in the calculation of specific model problems of optimization of chemical reactors is carried out.
Determination of the geometric characteristics of fatigue cracks by digital image processing method
Authors: Bazaron S A , Damdinova T Ts , Bochektueva E B
Published: November 2019

The article deals with the problem of determining the rate of crack growth in the process of fatigue failure of helicopter part samples. The studies were conducted using a video recording of the experiment. Methods of digital image processing were applied to the frames of the video recording to process the data of the object destruction process. Based on the developed algorithm, computational experiments were carried out, the geometric parameters of the cracks were determined for calculating the rate of change in their sizes. The use of digital image processing methods allows significantly improve the accuracy and reduce the processing time of experimental data.
Strength evaluation of the relocatable building made of the polymer composite material
Authors: Bokhoeva L A , Baldanov A B , Kurokhtin V Yu
Published: November 2019

The article deals with the problem of improving the efficiency of the frame relocatable building structures by perfecting structural forms, introducing sound and lightweight materials, in particular, polymer composite materials (PCM). For this purpose, we have developed an engineering calculation algorithm using CAD / CAE systems and considered various options for deposition of PCM layers. The analytical formulas that determine the Eulerian instability for PCMs are compared with the values in ANSYS.
An experimental research of the laminated composite plates stability
Authors: Bokhoeva L A , Bochektueva E B
Published: November 2019

The article shows the results of experimental studies of stability, supercritical behaviour and fracture of plates of a layered composite material. Composite plates are made of fiberglass layers glued with epoxy resin. To reliably assess the bearing capacity of laminated plates, numerical and experimental methods are used. A methodology for experimental research of the deformation and strength properties of composite materials using testing equipment has been developed. The difference between the critical strength values of three-layer samples and the critical strength of four-layer samples was determined to be 2-3%. Thus, products from composite materials (unmanned aerial vehicles) can be made from three-layer plates to reduce their weight. Models of two-layer, three-layer, and four-layer plates were performed with the ANSYS program. The obtained experimental results were compared with numerical values. The possibility of using experimental data of the mechanical behaviour of layered composite materials in the design and calculation of unmanned aerial vehicles was estimated.
Mechanical properties of self-compacting concrete containing sandstone slurry
Authors: Gupta R C , Basu P , Agrawal S
Published: November 2019

India embraces wide variety of dimensional stones. It includes granite, marble, sandstone, limestone and slate. Amid all the states, Rajasthan is known as mineral majestic of India, with an abundance of important stones. Rajasthan produces more than 90% of sandstone of all over the country. The total quantity of mined out sandstone is 200.27 million tons per year, out of which 110.25 million tons are accounted as waste during various manufacturing and processing stages of sandstone. An experimental work has been conducted to manufacture self-compacting concrete (SCC) with dry sandstone slurry (DSS) and study the properties of SCC. Seven SCC mixes have been prepared with various percentages of sandstone slurry (i.e. 0, 5, 10, 15, 20, 25 and 30 percent) as partial replacement of pozzolana portland cement (PPC). Compressive, flexure and tensile strength of all SCC mixes up to 180 days curing age and abrasion resistance after 28 days curing age have been found out and presented in this paper. The conclusion of this study draws an idea about the use of SCC mixes made with DSS are in favor of using DSS up to 10% for reinforced cement concrete work and up to 20% for plain cement concrete work.
Rheological properties of two stainless steel 316L powders for additive manufacturing
Authors: Gong Haijun , Xing Xiaodong , Gu Hengfeng
Published: November 2019

This study measures the rheological properties of two stainless steel 316L powders which are used for the powder-bed-fusion based additive manufacturing process. The purpose is to evaluate the newly acquired powder in comparison with the used and recycled powder, so that both powders can be mixed with each other to supplement the powder usage. The powder rheology properties, such as dynamic property, bulk property, and shear property, are tested and compared. The results and analysis confirm the compatibility of powder mixing.
Influence of varied process parameters on the microstructure, densification and microhardness of spark plasma sintered Ti-6Al-4V/h-BN binary composite
Authors: Abe J O , Popoola A P I , Popoola O M
Published: November 2019

The influence of varied process parameters involving three levels of temperature, pressure, heating rate and dwell time on the microstructure, densification and microhardness of spark plasma sintered Ti-6Al-4V/h-BN binary composite was studied. Taguchi design method was adopted to randomize the SPS process parameter levels. The microstructure was analyzed by optical microscopy, densification was determined based on the principle of Archimedes and Vickers microhardness tester was used to evaluate the microhardness of the sintered composite. The consolidation of Ti-6Al-4V powder and nanoparticles of 3 wt.% of h-BN via SPS produced nearly full theoretical densification of 99.77% and the sintered composite gave a microhardness value of 710.37 HV which is more than 200% that of the monolithic alloy. The best combination of relative densification and microhardness were obtained at the sintering parameters of 1000 °C of temperature, 40 MPa of pressure, 100 °C/min heating rate and 15 min of dwell time. Generally, it was found that improved microstructure, densification and microhardness were influenced by the high temperature of sintering and low rate of heating that gave room for adequate diffusional mass transport resulting in solid bonding between the particles of the matrix and the ceramic reinforcement.
Wear and surface roughness analysis of machining of Ti-6Al-4V under dry, wet and cryogenic conditions
Authors: Ali Khan Muhammad , Husain Imran Jaffery Syed , Khan Mushtaq , Ikramullah Butt Shahid
Published: November 2019

Use of cooling media contributes in elevation of desired responses owing to its cooling and lubrication effects especially in case of hard to cut materials like Ti-6Al-4V. This study aims to analyze the effect of cooling media in addition to cutting speed on responses including tool wear and surface integrity during turning. Results highlighted the effectiveness of cooling system in particular that of cryogenic media. Use of cryogenic media and cutting fluid enhanced tool life max by 33% and 21% respectively. At lower cutting speed surface roughness was improved by 13% and 8% by cryogenic media and cutting fluid respectively.
Tall buildings seismic behavior comparative study by increasing the concrete mechanical strength through non-linear static analysis and seismic performance
Authors: Lopez-De-La-Cruz F , Choncen-Arboleda A , Moreno-Sanchez J
Published: November 2019

The use of high strength concrete in tall buildings implies less lateral displacement, however, an important question is. In what other measures the seismic behavior of a building improves with high strength concrete (550 kg/cm2). As a result, the material allows the construction of slender structural elements, however we won’t be able to know how much the ductility of the structure in front of a seismic event will improve. Therefore, the reason of this study is to analyze the dynamic response of a tall building with different sections and resistance to the compression of its structural elements. The aim of this study is to obtain the curve of capacity and the point of seismic performance of each structural model.
Analysis of surface treatment of ASTM A516 Grade 70 using Salt spray method
Authors: Ali Khan Muhammad , Shah Aqueel , Husain Imran Jaffery Syed , Khan Mushtaq , Rasheed Khan Adnan
Published: November 2019

Conversion coating is an effective way to safeguard against corrosion. It is performed on a number of materials inhibiting the surface layer to corrosive attack. In this work surface engineering is carried out on test material ASTM A 516 Grade 70 which is widely used for constructional purposes. During the passivation process samples were given a hot alkaline oxide bath in sodium hydroxide and sodium nitrate. The corrosion resistance was then analyzed using advanced testing procedures. Salt spray test was used as a yard stick in making a comparative analysis of different samples including unpassivated samples, passivated samples and passivated samples with prior surface treatment. Results have shown that mechanical surface treatment improves material life by 3% whereas passivation with prior surface treatment can increase life by 18%.
Effect of Internal BN Substitution on Electronic Properties of Pyrene Derivatives
Authors: An Li
Published: November 2019

Pyrene as an important chemical building block has found wide applications in the field of organic electronics. In solution, pyrene and its derivatives are well-known examples for excimer formation. Here, we studied the boron-nitrogen (BN)-substituted pyrene, decorated with thiophene side chain. From density-functional theory (DFT) calculation, this isoelectronic BN substitution maintains the coplanarity of the central motif and the delocalized π-electron distribution, but additionally induces a much stronger permanent dipole moment. Time-dependent DFT indicates a much-reduced oscillator strength for low energy transitions, and surprisingly a forbidden π-π* transition, therefore resulting in a much red-shifted absorption spectrum. Our simulation results call for future experiments to study the photo-excited properties of BN-substituted pyrene and molecular self-assembly through dipole-dipole interaction and π-π* interaction.
Alpaca Waste Management Model for Improving Fiber Productivity Through the use of Biomass in Andean Highland Communities
Authors: Fernandez-Lizama V , Espinoza-Ccatamayo A , Chavez-Soriano P , Raymundo-Ibañez C
Published: November 2019

In an environment where the international market demands a large amount of fiber, the countries that produce raw material must be prepared to face the fulfillment of exports. However, it must be noted that in majority of the countries, this fiber, such as alpaca, can be found in the mountains at more than 3, 000 MASL where frosts are constant and cause deaths. Likewise, if the collection of feces is not adequate, it can represent an infectious focus which, in addition to the deaths, would reduce the productivity of the fiber. Thus, we can say that the main cause is the incipient knowledge of sanitary practices. This document proposes an alpaca waste management model for the generation of biogas for heating alpacas in frost seasons and obtaining biol for the improvement of pastures. The stages in which the project is carried out include infrastructure of the house, connection of house alpaca and system of drainage, biodigester, improvement of pastures. This model was validated by means of a continuous biodigester prototype supplied with alpaca feces and pig biol achieving 1 of biogas.
Interconnected State Control Method and Simulations of Four-corner Interconnected Air Suspension
Authors: Zhongxing Li , Ying Zhou , Xiao Zhang , Hong Jiang , Hongtao Xue
Published: November 2019

The four-corner interconnected air suspension can effectively improve vehicles ride comfort, but the opening of the interconnection will intensify the roll or pitch of the car body, reducing the vehicle handling stability when the vehicles are in the turning, acceleration and deceleration conditions. To solve the above problems, an interconnected state control method is proposed for four-corner interconnected air suspension, the interconnection state of the pipeline is determined by the relationship between the torque produced by the air spring and the roll angles or pitch angles of the car body. The parameters of air spring pressure, car body roll angle and pitch angle are used in the control method to obtain the optimal interconnection state of four interconnected pipelines through control algorithm calculation. Finally, the opening and closing of four interconnected pipeline solenoid valves are controlled. In order to verify the effectiveness of the control method, the MATLAB/Simulink model of four-corner interconnected air suspension is established and simulated.
Study on the ultimate load carrying capacity of journal bearings with different materials and surface treating processes
Authors: Li Hulin , Wang Yanzhen , Yin Zhongwei
Published: November 2019

The ultimate load carrying capacity of journal bearings with different materials and surface treatment processes was studied in the present work. The load carrying capacity and backside temperature of bearing were examined using a bearing fatigue test machine (Glacier Vandervel, made in UK). The results showed that the copper-based sputtering bearing has the highest ultimate bearing capacity and the fatigue strength reaches 131.3 MPa. The bearing capacity of copper-based electroplated bearings is 99.7 MPa, which is lower than that of copper-based sputtering bearings. The bearing capacity of high tin aluminum alloy is obviously higher than that of white alloy bearing, and the bearing capacity of the two bearings is 72.7 MPa and 36.3 MPa, respectively. Finally, the mechanisms of fatigue failure of the bearings were analyzed.
Electromechanical Device for Temperature Control of Internal Combustion Engines
Authors: Mamani A , Quispe G , Raymundo-Ibañez C
Published: November 2019

Internal combustion engines are the most commonly used engines in the automotive world. However, these engines lack an overheating prevention system against cooling system failures when they exceed their normal operating temperature. Less experienced drivers (users) usually do not notice overheating until the engine stops, generating economic expenses in engine repairs. As such, this paper describes the design and construction of an electromechanical device to prevent engine overheating. This device is installed in a vehicle and operates independently from the electronic control unit (ECU); it records the coolant temperature and controls air admission to the engine of the vehicle in which it is installed. In addition, a new Arduino-based card will receive signals from a temperature sensor as input and process them according to its programming. Then, it will send signal outputs to the actuators: a servomotor, monitor, LED display, and buzzer. To control the intake flow, a butterfly valve is used with the servomotor. This valve partially or totally restricts the engine airflow, based on the temperature programmed for the Arduino, thus protecting the engine from overheating.
Ventilation System Simulation Model at a Mine
Authors: Artica I , Quispe G , Raymundo-Ibañez C
Published: November 2019

This research project modeled and simulated a ventilation system at a Mining Concession, obtaining real-time information regarding the fans used to ventilate the mine. The simulation was developed using the VENTSIM 5 software, which also helped define the number of fans and the operating parameters required, field information, mine dimensions, the mining method, production, geothermal gradient, gas emission, air stream, and air pressure. In addition, the results from software operation revealed the need to open chimneys and use fans. Furthermore, the results also suggest that a specialist dedicated to ventilation and fan maintenance must be hired to formalize mining operations as per the Occupational Safety and Health Mining Regulations from Executive Action No. 024-2016-EM as this Mining Concession is currently operating without license.
Applying Lean Manufacturing Principles to reduce waste and improve process in a manufacturer: A research study in Peru
Authors: Kaneku-Orbegozo J , Martinez-Palomino J , Sotelo-Raffo F , Ramos-Palomino E
Published: November 2019

In the present scenario, lean manufacturing techniques are the most successful improvement concepts that many companies can apply in order to eliminate waste and non-value-added activities related to the manufacturing process. This paper discusses the implementation of lean manufacturing tools and an integrated framework between production planning and quality in a SME dedicated at a production of kitchen equipment. Studies of the company processes showed that the cutting and bending processes tend to create the most amount of sheet metal waste and non-value-added activities. The main objectives of the research were to standardize work, reduce waste, eliminate machine failures and develop the guidelines for a correct planning that meets quality requirements. The improvement results have shown a positive impact reducing the waste ratio and this has meant a saving of 13% in the manufacturing cost.
Creating a High and Homogenous Resolution Workspace for SCARA Based 3D Printers
Authors: McClinton Essence , Wylie Brianna , Moore Dr. Carl A.
Published: November 2019

3D printing is an additive manufacturing process that has an untold number of applications in fields as diverse as medical prostheses to military vehicle manufacturing not to mention its long term use in component prototyping [1][2]. With the creation of robotic arm based printers, the 3D printing process can be improved in terms of flexibility and time-efficiency, but with the potential trade-off being lower resolution in some areas of printer workspace. To counteract the resolution reduction, we are studying the use of continuously variable transmissions (CVTs) coupled to the robot’s traditional revolute joints [3]. This paper will show that CVTs allow our SCARA-based robotic printer called DEXTER to achieve a resolution as good or better than a traditional desktop style 3D printer.
Artificial Intelligence in the Aviation Manufacturing Process for Complex Assemblies and Components
Authors: Ian McAndrew , Elena Vishnevskaya , Michael Johnson
Published: November 2019

Aviation manufacturing is at the leading edge of technology with materials, designs and processes where automation is not only integral; but complex systems require more advanced systems to produce and verify processes. Critical Infrastructure theory is now used to protect systems and equipment from external software infections and cybersecurity techniques add an extra layer of protection. In this research, it is argued that Artificial Intelligence can reduce these risks and allow complex processes to be less exposed to the threat of external problems, internal errors or mistakes in operation.
Multi-scale model retrieval for case recommendation in manufacturability optimization
Authors: Li Zhi , Zhou Danchen , Zhang Bo
Published: November 2019

This paper proposed a multi-scale retrieval framework to help optimize manufacturability. The case based workflow integrates both geometry and rules with model-based definition. At conceptual stage, defect models are categorized and global retrieval is initialized to narrow down cases as defects references. At detail stage, local feature retrieval finds similar defect feature with pre-defined rules, to adapt to manufacturability optimization. Intersection feature detection and decomposition are explored to improve generality.
Mooring systems analysis of floating wind turbines in Italian seas
Authors: Re P , Passoni G , Gudmestad O T
Published: November 2019

In recent years, interest in exploiting wind power in deep waters has grown, with the realization of floating structures that could accommodate a turbine and produce electricity. One of the many challenges that these projects face is the position keeping of the system in a defined part of the sea: this is carried out with mooring systems, designed to withstand extreme marine conditions. The first aim of this work is to analyze these systems, to find a general solution for a floating wind farm in the Italian seas. Of importance is to suggest a design that could be fabricated in an Italian dry dock and towed to site. A numerical model of the floating structure and the environment has been realized using the software, OrcaFlex, and simulating the 50- and 100-year return period conditions in the Adriatic Sea and in the Strait of Sicily, with different mooring combinations of present-day technologies. The model’s implementation requires environmental and structural parameters: the former have been obtained with a statistical analysis of actual recordings of wind speed and wave height and with the official Italian cartography. Structural details have been derived by looking at existing floaters, finding the most suitable one for the Italian environment. After simulations, the results are interpreted with a comparison of tension in the lines, vertical forces at the anchors, wire length and mooring footprint, finding out that depth has the greatest impact on these factors. With respect to this, the proposed numerical model can provide a simple indication for the mooring of floating wind turbines in two different areas of the seas surrounding the Italian peninsula: for the Adriatic Sea (shallow waters), suction anchors with chains should be preferred, while, for the Strait of Sicily (deeper waters), traditional anchors may be considered, with lines composed of chains or a combination of chains with synthetic fibers.