bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geochemical Distribution of REE and Grain Size Analysis of Heavy Mineral Associated with Tin Placer-Type Deposit, Bangka
Authors: Syafrizal  , Hakim AYA , Sulastri A 
Published: May 2022

Abstract
Indonesia is included in the East Malaya Block of the Southeast Asian Tin Belt. Two types of tin deposits in Indonesia are primary and secondary tin deposits (placer). Factors that can cause the formation of placer tin deposits include S-type granite, weathering, transportation, and sedimentation. Factors that control the formation of placer tin deposits include the presence of source rock (granite type S), weathering processes, erosion, transportation and sedimentation, and the presence of basins or valleys where weathering materials are deposited. The transportation process has a major role in the grain shape of a material. This study aims to determine the geochemical distribution and characteristics of heavy mineral grains at the accumulation of placer tin deposits, e.g., colluvial, alluvial, and tailings, in which there are 62 sample points located Bangka Island, Indonesia. The research method used in this study was grain size analysis, radiation level measurement using a scintillometer, and geochemical analysis using ICP-MS.
Study of Water Balance for Tropical Peatland Restoration Case Study: Sinarwajo Village, Jambi Province, Indonesia
Authors: Fauziah S.N. , Widodo L.E. , Ramdan H. 
Published: May 2022

Abstract
Efforts to restore degraded peatlands that have declining groundwater levels are carried out to prevent disasters such as forest fires and carbon emissions into the atmosphere. At present, peatland restoration is an essential topic for researchers, especially regarding hydrological restoration (the re-wetting). Water balance calculation is needed in providing hydrological information and supporting re-wetting of degraded peatlands. In this paper, a study of water balance was conducted for peatland re-wetting in Sinarwajo Village, the Province of Jambi. The result showed that the evapotranspiration budget is 56% from the rainfall. Besides, run-off and groundwater storage is about 32% and 12% respectively. This information can be a primary goal of re-wetting, so the efforts of re-wetting should increase more groundwater storage and limit the water discharge from peatland.
Focal Mechanism Analysis of the Earthquakes Beneath the Sunda-Banda Arc Transition, Indonesia, Using the BMKG Data
Authors: Supendi Pepen , Rawlinson Nicholas , Nugraha Andri Dian , Widiyantoro Sri , Abdullah Chalid Idham , Daryono  , Prayitno Bambang S. , Sadly Muhammad , Karnawati Dwikorita 
Published: May 2022

Abstract
Structural complexity in the Sunda-Banda arc transition is a topic of much debate amongst Earth scientists. We have processed focal mechanism study using moment tensor inversion for 20 events in the region using the Agency for Meteorology, Climatology, and Geophysics (BMKG) data from 2014-2016 for earthquakes of magnitude Mw ≥ 5.0. Our result shows different solutions that depend on the source region of the earthquakes that include subduction zones and collision zones, which host active faults and the back-arc thrusts. Earthquakes that occurred in the subduction zone appear to rupture on thrust faults for shallow and intermediate events, while the deep events have normal fault mechanisms. The shallow events in the collision zone occur on thrust faults with differing strike directions, but generally, there are largely parallel to the Timor trough. We also found normal fault mechanisms at play for deep events below the collision zone. The occurrence of deep earthquakes in this area is consistent with remnant slab activity that persists to the present day. Focal mechanism solutions for shallow events in the north of Sumbawa island indicate a thrust fault with a strike direction that is almost parallel to the back-arc thrust in this area. We also found evidence of strike-slip motion along local-scale active faults in the area.
Iterative 2D Gravity Modelling for Basement Depth Estimation
Authors: Ariesti Faradilla Thelma , Grandis Hendra 
Published: May 2022

Abstract
In gravity modelling, iterative refinement of 2D basement geometry is a classical problem where the density contrast has to be determined in advance. We present a relatively simple method to estimate 2D basement depth along with its density contrast. Known basement depths at several points and their associated gravity anomalies determine the gravity - depth relationship that is used to obtain the first estimate of the overall basement depth. The initial model response is calculated with a unitary density. The linear regression between calculated model response and actual gravity data results in the density contrast estimation. The misfit or residuals and the gravity - depth relationship are used to update the model iteratively. The proposed technique is relatively stable and results in a recovered model quite similar to the synthetic model. We also explore the possibility to include estimation of the constant the regional anomaly.
Geothermal Potential in a Small Volcanic Island
Authors: Achmad Rahim , Salam Ramdani 
Published: May 2022

Abstract
In this paper we report the continuation of previous observation of hot spring phenomenon in northern Ternate island. The hot spring distribution spread unevenly with temperature ranging from 29 °C to 35.5 °C along shore line. Geomagnetic measurements, chemical water and physical water properties have been carried out to find the caused of unevenly hot spring distribution . This research intends to reveal geothermal potential in a small volcanic island. The result of geomagnetic measurements, showed low magnetic anomalies as demagnetization rock by heat. Magnetic anomaly map shown any fault structure alignment with the northeast – southwest. The fault structures create path of heat. The result of chemical and physical water properties also agree with geomagnetic measurement that show indication of geothermal system. The heat source comes from magma chamber and passes through rock fractures (fault) as known as up flow geothermal system.
Identification Protocol of Yoshida-Uemori Hardening Model
Authors: Lemoine X , Chichery Q , Devin J M , Duroux P 
Published: May 2022

Abstract
The Yoshida-Uemori model is a combined hardening model coupled with the elastic modulus evolution which depends on the equivalent plastic strain. A lot of publications show that it allows to improve the springback prediction compared to a classical isotropic hardening model. It is implemented in the most used FEA stamping codes (Autoform®, Ls-Dyna® and Pamstamp®) with some variations and it is more and more used in automotive industry. ArcelorMittal decided to provide material cards to its customers. To achieve this goal, ArcelorMittal has at one’s disposal the equipment to perform reverse shear tests and hysteresis loops for all steel grades. An in-house methodology has been developed to identify the Yoshida-Uemori adjusting parameters in a very precise and robust manner. The material cards are produced for each FEA stamping code, considering the specificities of the implementations.
Phenomenological-based constitutive modelling of warm deformation behavior of high-Strength lightweight AL-Li alloy sheets
Authors: Abd El-Aty A , Xu Y , Zhang S H , Guo X , Tao J , Lee M G 
Published: May 2022

Abstract
The flow behavior and formability of Al-Li alloys under warm forming conditions are complicated because they depend on several factors, such as the deformation mode, strain, and strain rates. Therefore, characterizing the mechanical response, and deformation behavior of AA2060-T8 sheets under a wide range of temperatures and strain rates is crucial to develop a new thermo-mechanical processing (TMP) route for their wide industrial applications. Furthermore, determining the activation energy (Q) and predicting the flow behaviour of AA2060-T8 sheets under warm forming temperatures is meaningful for characterizing the mechanical response of AA2060-T8 sheets at warm deformation conditions. Thus, in this study, the Arrhenius constitutive model is developed to investigate the influence of strain rate and temperature on the warm deformation behaviour of AA2060-T8 and determine the activation energy (Q) of AA2060-T8, which is a crucial physical parameter to estimate the difficulties of deforming AA2060-T8 sheets under warm forming conditions.
Less damage accumulation of aluminum alloy sheet during electromagnetic forming based on Gurson-Tvergaard-Needleman model
Authors: Liu W , Zhou H , Meng Z , Li J , Huang S 
Published: May 2022

Abstract
The formability of aluminum alloy sheet is usually improved during electromagnetic forming (EMF). Here, the ductility enhancement mechanism was investigated on the basis of Gurson-Tvergaard-Needleman (GTN) model. The parameters of GTN models under quasi-static tension and EMF conditions were respectively determined by inverse identification. For AA2024-O aluminum alloy sheet under quasi-static tension, the initial void volume fraction is identified as 0.006, the critical void volume fraction where voids begin to aggregate is 0.075, the void volume fraction of nucleating particles is 0.131 and the mean nucleation strain is 0.44. With the similar initial void volume fraction, the other parameters under EMF condition are determined as 0.045, 0.055 and 0.58. The evolution curve of void volume fraction with strain were compared under EMF condition and quasi-static tension. The results show that the total growth of void volume fraction is less under EMF condition than that under quasi-static tension. A box part with inclined flange was preliminary achieved by electromagnetic forming process. The GTN model was finally verified by comparing the numerical and experimental results.
Numerical analysis of a backward flow forming operation of AA6061-T6 and comparison with experiments
Authors: Mocellin K , Vidal M A , Frascati F , Bouchard P O 
Published: May 2022

AbstractIncremental forming processes can be used to produce thin products (tubes or sheets)[1]. Very high deformation of the material can be reached taking advantage of the local and cyclic loading of the material. In this study we will focus on backward flow forming of aluminum tubes. In this process, tube thickness is reduced by the combined action of a rotating mandrel that imposes the inner radius and 3 rollers that decrease progressively the tube thickness. An experimental campaign is conducted on a laboratory device to study the influence reduction rate. The corresponding configurations are simulated to understand the mechanical loading path. The material characterization is presented to focus on the influence of the chosen behavior law on flow forming simulation results. Different damage criteria coming from the literature are studied to evaluate their capability to predict fracture and to compare the amount of damage reached for each process configurations. Even if none of them is able to predict accurately damaging configurations, the classical Cockroft and Latham seems to be the only capable to reflect the hierarchisation of configurations.
Investigation on the formability of friction stir welded Al-TWB through incremental forming
Authors: Shubham  , Nayak Kiran K , Teja Pilli J , Jain Rahul , Bandyopadhyay Kaushik 
Published: May 2022

Abstract
In the quest for weight reduction, automobile industries introduced the technology of tailor welded blanks (TWB) which offered utilization of material as per functional requirement. In general, friction stir welding (FSW) is mostly used for fabricating aluminum based TWBs as fusion welding of Al—alloys are problematic. Recently, single point incremental forming (SPIF) gained popularity among researchers as well as in industry as a dieless flexible forming technique. Hence, in this study two aluminum sheets namely AA6061 and AA7075 of similar thickness were welded together using FSW with square pin. The formability of the TWBs were evaluated in terms of cup height, wall angle and fracture location through SPIF incorporating different tool geometries. To assess the effect of weld, similar welded Al blanks were also deformed in the similar condition. The formability of the similar welded blanks and corresponding parent metals did not differ much and fracture did not initiate at the weld. However, cup depth for the TWB was in between the cup heights of the parent metals and failure was not observed at the weld region. TWB cups did not show any weldline shift.
Deep drawing of DC06 at high strain rates
Authors: Tulke M , Galiev E , Psyk V , Kräusel V , Brosius A 
Published: May 2022

Abstract
Velocity effects in production technology provide technological and economic advantages, but they require consideration of strain rate dependent material behaviour in numerical process modelling. This paper proposes a deep drawing process with DC06 at high strain rates of up to 100 s-1. Basis of the investigation are the results of the inverse parameter investigation at high strain rates in [1]. In addition to the velocity dependent flow curve in numerical modelling, the damage parameters are also taken into account. The drawing ratio and the punch velocity that affects the strain rate and the stress state in the deep drawing process are varied while the blank holder force is constant. Due to the high punch speed and the pronounced inhomogeneity of the strain rate over the work piece volume, the punch speed and punch force is very well suited to verify the numerical results. Additionally, the mesh dependency of the temperature evolution in the sheet metal is examined for further investigations of the adiabatic heating of the work piece during deformation in experiment and simulation. In this context, the deep drawing tools as well as the results of the numerical and experimental investigations are presented and discussed.
Post necking evaluation of the tensile test using artificial neural networks
Authors: Hakenbeck F , Lafarge R , Brosius A 
Published: May 2022

Abstract
This paper introduces a new method for evaluating the tensile test using finite element simulations and data-driven artificial neural networks. For this purpose, a synthetic data set was generated by finite element simulations using LS-DYNA. Artificial neural networks of two different topologies were trained and tested on parts of this synthetic data set. The networks use geometry information of the necking area as input data to predict a correction factor to convert the stress obtained from the tensile test to the equivalent flow stress. The best models are evaluated on the test set and good results are achieved.
On the use of elliptical bulge tests in material characterization through inverse methodologies
Authors: Rossi M , Lattanzi A 
Published: May 2022

Abstract
The hydraulic bulge test is an experimental technique that can be used to identify the properties of sheet metals up to large strain. The hydraulic bulge test, usually, is a free expansion of a sheet blank through a circular hole, driven by the pressure of a fluid, where the ends of the blank are blocked using a suitable die. The state of stress during the bulge test is mainly equi-biaxial, however, using elliptical holes with different aspect ratios, it is possible to produce heterogeneous stress-strain fields that can be used to identify the properties of the material through an inverse method; in this case, the non-linear Virtual Fields Method (VFM) was adopted. With respect to the traditional tests employed with the VFM in plasticity, i.e. double notched specimens or specimens with holes subjected to tensile tension, elliptical bulge tests allow to investigate a different zone in the stress-strain space, with a higher triaxiality. The capability of this type of test to calibrate the parameters of advanced anisotropic models is here assessed using simulated experiments.
Investigation of frictional behavior of steel and aluminum at different temperatures
Authors: Huang G , Fenton F 
Published: May 2022

Abstract
In order to evaluate the performance of the press line, it is essential to investigate the frictional behavior and properties of materials under production temperatures. In servo press line production conditions, the tooling temperature can reach 45-55 °C after around 150 stampings. In this investigation, a clamping fixture with drawbead and flat plate inserts was employed to conduct the friction tests at room temperature and an elevated temperature (54 °C). Three mild steels and two aluminum grades (5000 and 6000 series) were used in the tests. The results from drawbead tests showed that friction force on the two aluminum materials increased by 10% at 54 °C compared to that at room temperature. However, for the 3 steels the change of friction force was negligible from 22 °C to 54 °C. This implies that for exposed panel applications, the selected steel grades might have a more controlled sliding behavior potentially resulting in better control of formability than aluminum grades for the range of temperatures observed during production stamping.
A data-driven methodology for separately quantifying the effects of tool wear of upper and lower tool on the quality of cut surfaces in shear cutting processes
Authors: Niessner S , Liewald M 
Published: May 2022

Abstract
Shear cutting processes are characterised by physical parameters that change in time and space because of influencing process effects. Those parameters partwise can be measured and recorded by sensors and assigned to causal process effects through detailed evaluation based on analytical models. If the analytical model can classify the causal process effects in detail, the quality of the processed sheet metal component can be monitored on the basis of knowledge about tool wear influences and so a permanent part quality only can be ensured by a preventive tool change. In detail, the quality of the cut surface of a shear cut component to be assessed in this process is influenced by both the tool wear effect of the upper and lower tool, whereby both in fact show a significant influence on the different dimensional and surface characteristics of the cut surface. Analytical models for such analysis often are not available, or, if available, it may deliver only proximate results that needs improvement for the respective process effects. Previous procedures for such prediction purpose are frequently based on large and complex neural networks that require as well as process a huge amount of data.
In this regard, a novel evaluation method has shown great potential for data-driven quantification of tool wear effects and looks capable of far outperforming previous process evaluation methods in its performance under different process conditions. In previous studies, specific upper and/or lower tool wear was not considered in a separate manner and a detailed inspection of the finished cut surface there for could not be carried out. This paper investigates how a data-driven approach can be used to evaluate specific wear effects of upper and lower tools in a differentiated manner, and in which degree of detail the main quality characteristics of the cutting surface in a shearing process thus can be assessed.
Field meta modelling for process design in complex sheet metal forming
Authors: Schwarz C , Kriechenbauer S , Mauermann R , Drossel W G 
Published: May 2022

Abstract
Actually, new applications of machine learning methods like variance-based sensitivity analysis take place for developing complex sheet metal forming and joining processes. The application of this methods will help to quickly start of production when the simple numerical designing of the processes becomes too complicated. Two investigated examples show the application of the method for complex planning situations. The first one uses variable functions of force and motion during deep drawing to extend the process limits. The second one describes the complex clamping of an assembly of different sheet metal parts. Field meta modelling approaches are shown to automate tasks, visualize results and support engineers to plan and run different complex processes regarding sheet metal parts.
Control of draw-in in the deep-drawing process by regulating the force on the blank holder
Authors: Palmieri M E , Tricarico L 
Published: May 2022

Abstract
Sheet metal forming processes are strongly influenced by process parameters, moreover fluctuations during the process and in material properties often lead to robustness problems. Therefore, numerical simulations as a function of design and noise parameters are usually adopted to detect ahead critical regions. To ensure efficiency and quality, the new era of industry 4.0 aims to develop systems that can control critical issues online. The aim of this work is developing a methodology that allows to adjust the force on the blank holder to obtain an optimal draw-in profile. This latter assures a minimization of defects (e.g., compression areas, thickened areas, insufficient stretch areas, splits) on the final component, even when variability of friction coefficient and yield strength occur. This methodology is applied to the deep-drawing process of a component obtained from a DC05 steel sheet with a thickness of 0.75 mm. For this purpose, Finite Element (FE) simulations in AutoForm software have been performed as a function of the design parameter i.e., Blank Holder Force and of noise parameters i.e., friction coefficient and yield strength. The results explored to evaluate the quality of the stamped part are: (i) percentage of compression areas, (ii) thickened areas, (iii) insufficient stretch areas, (iv) excessive thinning areas and (v) areas with splits. The data collected from FE simulations were adopted to perform a multi-objective optimization by means of the desirability function approach. Consequently, the value of process parameters that minimize defects (high value of total desirability) were identified. In correspondence with this optimal solution, the optimal draw-in profile was obtained. Such optimal profile was compared with the draw-in profile which involves defects on the final component (non-optimal draw-in profile). This latter was obtained for a value of the force on the blank holder equal to the optimal one and for non-optimized values noise parameters. In fact, noise parameters are not controlled process parameter. Based on the point-by-point difference between the two draw-in profiles, a numerical control strategy was implemented using AutoForm and MATLAB software. This iterative strategy allows to modify step by step the force on the blank holder so that the non-optimal draw-in profile match with the optimal one. Finally, experimental tests on a 3000 kN hydraulic press were performed to verify FE results.