Unloading Process Research Articles

PENGARUH DARI RITASE KENDARAAN TERHADAP PENDAPATAN KENDARAAN ANGKUTAN BARANG DI PANDAAN PASURUAN JAWA TIMUR


 Expedition company as the transportation company are have very important roles in goods flow chain from one place to the other places. In addition, with their capability and skill, the expedition service can organize of delivering implementation through land, sea, and air. Thus the expedition are offers more services for trading (transporting/acceptance) of the goods from the producer until to the consumers. One of the company that provides goods expedition services which operates in Pasuruan to fulfill the need of goods expedition services. The objectives of this research are to analyze whether the trips gaining of the vehicles that are supported by variables of loading and unloading process, distance of the good delivering, physical condition and traffic eftfae road, driver behavior, and vehicle condition are have significant effects on revenue of each freight vehicles. Population that used in this research are all of vehicles that existing in the company by amount of 50 vehicles. The methods of data analysis that used are validity, reliability and regression analysis test.

An integrated study of physical and numerical modelling on the stability of underground tunnel influenced by unloading rate

Excavation of tunnel is the unloading process of surrounding rock, and the unloading rate is one of the important factors affecting the stability of underground tunnel. Through the combination of large-scale physical model test and numerical simulation, combined with the water bag filling technology to simulate high-speed unloading excavation, the influence of unloading rate and unloading magnitude on the stability of surrounding rock of underground tunnel is quantitatively analysed according to the crack depth, displacement and stress concentration of surrounding rock. The results show that low-speed unloading produces closed arc-shaped cracks on both sides of the tunnel, while high-speed unloading produces closed circular cracks around the tunnel surrounding rock. Tunnels excavated with low-speed form wedge-shaped cracks and flaky destruction. The cracks distribute on the left and right sides of the tunnel, and form closed arcs. Tunnels excavated with high-speed form wedge-shaped closed cracks, which are circularly distributed around the tunnel. The crack depth of tunnel surrounding rock caused by low-speed unloading is larger than that caused by high-speed unloading, and the local stress concentration of low-speed unloading is also more obvious in the sidewall of the tunnel. However, the overall stress of the surrounding rock of the high-speed unloading is more significant, which means it accumulates much energy, and dynamic disasters may occur. High-speed unloading is more suitable for projects in low ground stress or soft rock mass stratum, which may cause less damage to the surrounding rock. In contrast, low-speed unloading can reduce the possibility of dynamic disaster for projects in high ground stress or hard, brittle rock mass.

LAYOUT REDESIGN OF CONTAINER SHAKIGNG FIELD AT PT. XYZ

The Layout of the Field Layout Stacking containers is an important thing to consider because it can affect the effectiveness of the loading and unloading process in the field by arranging the Layout of the facilities in the stacking field in the Yard Layout including the Rubber Gantry Crane (RTG) and the arrangement of the lane Head Truck. So, it is necessary to research determining the Layout of containers. The design that will be made will affect the distance the head truck travels to transport containers from the dock. In several studies, two types of determined, Layout have been container namely Parallel Layout where the containers are arranged parallel to the pier, and Perpendicular Layout where the containers are arranged Perpendicular to the pier. Container terminal Makassar New Port using Parallel Layout. To increase the productivity of the loading and unloading process, an analysis of the arrangement of the stacking field is carried out. From the results of the research, the farthest travel distance is 1,048 m, with a total travel distance of 729,269 m with a fuel cost of Rp. 1,144,952 in the initial Layout (Parallel Layout), with the Perpendicular Layout, the farthest travel distance is 353.7 m with a total travel distance of 473,533 m, and the use of materials burn 743,446.8 m

Energy dissipation of mechanical metamaterials composed of multilayer buckling elements

The effect of layer number, buckling sequence and drive velocity on energy dissipation per buckling event of mechanical metamaterials composed of representative volume element (RVE) is studied. Buckling behaviors of a single RVE encompassing buckling beams are investigated based on an approximate model. The metamaterials are modeled as a tandem model composed of identical RVEs. The buckling behavior can not induce energy dissipation if for the proposed structure. As or drive velocity increases, energy can be dissipated during elastic buckling. Besides, the dissipated energy per buckling event gradually decreases during one complete loading and unloading process.

PENGARUH DARI RITASE KENDARAAN TERHADAP PENDAPATAN PADA KENDARAAN ANGKUTAN BARANG DI PANDAAN PASURUAN JAWA TIMUR

Expedition company as the transportation company are have very important roles in goods flow chain from one place to the other places. In addition, with their capability and skill, the expedition service can organize of delivering implementation through land, sea, and air. Thus the expedition are offers more services for trading (transporting/acceptance) of the goods from the producer until to the consumers. One of the company that provides goods expedition services which operates in Pasuruan to fulfill the need of goods expedition services. The objectives of this research are to analyze whether the trips gaining of the vehicles that are supported by variables of loading and unloading process, distance of the good delivering, physical condition and traffic eftfae road, driver behavior, and vehicle condition are have significant effects on revenue of each freight vehicles. Population that used in this research are all of vehicles that existing in the company by amount of 50 vehicles. The methods of data analysis that used are validity, reliability and regression analysis test.

A digital twin for 3D path planning of large-span curved-arm gantry robot

Gantry robots enjoy important applications in unmanned factories and intelligent manufacturing tasks. Aiming at the automated production of customized wooden furniture, this paper proposes a digital twin for three-dimensional (3D) path planning of a large-span curved-arm gantry robot. First, a digital twin platform is built to show the door panel loading and unloading process of the gantry robot. Then the 3D path planning problem and method are proposed based on the built platform. The core of the algorithm consists of a bilateral control method, a 3D mesh construction strategy, and multi-objective 3D path planning using assembly line scheduling. The bilateral control method is used to achieve the perception and control of the gantry robot in the physical space. The mesh construction strategy entails static point set construction, obstacle avoidance analysis, point set construction for leap obstacles, and convex plane construction analysis. Multi-objective 3D path planning is primarily based on the NavMesh algorithm, which leverages an assembly line scheduling model to complete the wooden door processing task. Experimental results show that the proposed method can ensure safety, improved production efficiency, and satisfactory real-time performance in controlling the real gantry robot.

Study on Dust Suppression of Air Curtain Soft-Sealing System of Grab Ship Unloader

In order to suppress the irregular diffusion of dust in the unloading process of grab ship unloaders, an air curtain soft-sealing system was designed that can effectively block the air flow and restrict the diffusion of pollutants and reduce the average mass fraction of pollutants outside the air curtain plane by 70.02%. The grab unloading model was constructed using the Computational Fluid Dynamics–Discrete Element Method (CFD-DEM) coupling method, and the diffusion law of the gas–solid two-phase flow field of the falling bulk material was studied. Moreover, the motion trajectory and velocity distribution of the particle flow field and air flow field were obtained, as well as the maximum air flow field velocity of five planes above the hopper. The three-dimensional model of the air curtain jet was used and simplified, and the air curtain parameters were set based on the maximum air flow field velocity. The barrier performance of the air curtain under different air curtain jet modes, jet widths, jet velocities and induced wind velocities was simulated by the control variable method. The results show that selecting the appropriate jet widths and jet velocities can significantly reduce dust diffusion; under different jet modes, the order of influence was blow and suction, unilateral blowing and bilateral blowing; under a certain range of induced wind velocities, the air curtain had an obvious blocking effect. These results can provide a reference for the design and improvement of dust suppression of the air curtain soft-sealing system.

Numerical Simulation Analysis of Mechanical Properties on Rock Brittle–Ductility Transformation Under Different Loading Rates

At present, a large number of physical tests and numerical simulations have been carried out to study the effect of confining pressure on rock deformation mechanism, and some achievements have been achieved; however, the mechanism of rock deformation in actual mine engineering needs to be further studied, for example, rock-burst is actually a unilateral unloading process of rock mass, and this process can not be completed by physical test. RFPA3D was used to simulate the brittle–ductility transformation mechanical properties of rock under different confining pressures in this paper. The damage constitutive equation of rock was derived from continuum damage mechanics; the damage coefficients of different rocks were determined based on the numerical results of stress acoustic emission, so the correctness of rock damage constitutive equation was verified. According to the derived brittle–ductility damage equation and the fitting results of ductility cumulative damage data, it was found that the development trend of rock brittleness stage was almost the same, and the extended separation occurred after entering ductility stage. The larger the Poisson’s ratio was, the longer the ductility stage was. The smaller the Poisson’s ratio was, the shorter the ductility stage was, but the larger the bearing capacity was. At the late loading stage, the ductility cumulative damage of rock showed a linear upward trend, the bearing capacity sharply decreased, the rock stability failure occurred, and the ductility damage coefficient increased gradually. The study on the brittle–ductile mechanical properties of rocks can help to deep mine’s rock-burst prediction and prevention and has significant engineering significance.

Promoted mechanical properties and functionalities via Ta–tailored Ti–Au–Cr shape memory alloys towards biomedical applications

In view of the urgent demands of shape memory alloys (SMAs) for biomedical applications due to the world population aging issue, the mechanical properties and functionalities of the biocompatible Ti–Au–Cr–based SMAs, which are tailored by Ta additions, have been developed in this study. The quaternary SMAs were successfully manufactured by physical metallurgy techniques and their mechanical properties and functionalities were examined. In the continuous tensile tests, it was found that the correlation between the yielding strength and phase stability followed a typical trend of mechanical behavior of SMAs, showing the lowest yielding strength at the metastable β–parent phase. Functional mappings between the alloy strength and elongation revealed that compared to the Ta–free specimen, the ductility was promoted 50% while the strength remained intact through the 4 at.% introduction of Ta. Slight shape recovery was observed in the cyclic loading–unloading tensile tests during the unloading process and the highest shape recovery was found in the Ti–4 at.% Au–5 at.% Cr–4 at.% Ta specimen. This indicates that the 4 at.% Ta tailored Ti–Au–Cr SMAs could be a promising material for biomedical applications.

Using true-triaxial stress path to simulate excavation-induced rock damage: a case study

This study presents an example illustrating the role of in situ 3D stress path method in simulating the roof damage development observed in the Mine-by tunnel at Underground Research Laboratory (URL) located in Manitoba, Canada. The 3D stress path, at the point 1 cm in the crown of the Mine-by tunnel, was applied to a cubic Lac du Bonnet (LdB) granite sample to further understand the roof damage process and the associated seismicity. After careful calibrations, a numerical model was used to reproduce the experiment, which produced similar seismicity processes and source mechanisms. Acoustic emission (AE) events obtained from laboratory and numerical modeling were converted to locations in relation to the tunnel face and were compared to the field microseismicity (MS) occurring in the upper notch region of the Mine-by tunnel. The crack development and damage mechanism are carefully illustrated. The difference between tests and field monitoring was discussed. The intermediate principal stress (σ2) unloading process was carried out in numerical simulation to investigate its role in rock damage development. The results clearly showed σ2 could play a significant role both in damage development and failure mode. It should be considered when predicting the damage region in underground excavations. This study highlights the potential role of laboratory and numerical stress path tests to investigate fracture processes and mechanisms occurring during engineering activities such as tunnel excavation.

Investigations of Micro-Deformation in Monocrystalline Copper at Low Temperatures via Indentation.

Indentation experiments on differently oriented faces of monocrystalline copper were conducted to investigate the micro-deformation process at temperatures ranging from room temperature to 150 K. The morphologies and textures of the residual imprints were observed using electron microscopy. Distinct slip bands were observed inside the imprints at 150 K compared to smooth surfaces at room temperature. Molecular dynamics simulations were performed to identify the deformation process beneath the indentation region. The results showed that plastic deformation was inhibited with decreasing temperature, but elastic recovery during the unloading process was enhanced, resulting in inner slip bands (ISBs) being observable in the residual imprints. The performances of these ISBs were strongly associated with the angles between the indentation direction and major slip surfaces and could be considered microscopic forms on the surfaces of aggregated geometrically necessary dislocations (GNDs). This work helped reveal the micro-deformation mechanism of indentations inside imprints.

Control System Upgradation with Linear Actuator in Coil Unloading Machine

Abstract: In this paper, we are going to see about the project is to unload the coil for the dispatching process from metal plate to place in thermo coal with the help of linear actuator. The process of coil unloading is automated with the help of HMI, sensors, motors and linear actuator. This process is carried out through ladder logic methodology. The linear actuator application machine process is the machine based on the PLC (PROGRAMMABLE LOGIC CONTROLLER) controller. Earlier PLC controllers are huge programmed size, spare parts are rare, inbuilt programming that could not change as per the requirements and the absolute models which is difficult to learn. The cam shaft mechanism takes over time to assemble the coil position. And also coils pick up and drop step by step process is difficult.To overcome this problem used the advanced PLC controllers model SIEMENS-S7 1200 instead of earlier telemechanic PLC controller because in this SIEMENS-S7 1200 model PLC the HMI is used to display the coil positions.

Discrete element simulation on failure mechanical behavior of transversely isotropic shale under two kinds of unloading paths

Based on the discrete element method, a two-dimensional numerical model of shale with different bedding inclinations was established. Using this model, the macro-and meso-mechanical properties of bedded shale under different unloading paths and bedding inclination were studied. In this study, the damage mechanism of bedded shale during the unloading process is revealed. The simulation uses the displacement-controlled loading method, with a loading speed of 0.05 m∙s−1. The results indicate that the bedding inclination of the shale has a significant impact on both mechanical parameters and failure modes under unloading. The peak strength and the ultimate bearing capacity show a “U” shape trend under both unloading paths. Observations of maximum values are observed at β = 0° or β = 90° while observing the minimum values at β = 30°or β = 45°. The failure mode of shale specimens with β = 0° at lower initial confining pressure, the failure mode is splitting damage along the multiple bedding plans, which gradually changes to shear damage with increasing initial confining pressures crossing the weak surface. The failure mode of the specimens with β = 15–45° at different initial confining pressure is shear-slip damage along the bedding planes. And shale at β = 60–90° failure modes are all conjugate shear damage intersecting with the weak surface. The damage to the specimen caused by unloading and increasing the axial stress is greater than that caused by the unloading and constant axial strain. The effects of β = 0° and 90° on microcracking and stress distribution within the specimen are significantly smaller than for the other bedding inclinations.

Towards three dimensional aspects of plasticity-induced crack closure: A finite element simulation

The mutual interactions between intrinsic (damage) and extrinsic (shielding) mechanisms are essential for understanding fatigue crack growth in ductile materials. In the latter case, plasticity-induced crack closure is the dominating retardation mechanism in the Paris regime. The transition between plane strain and plane stress states leads to a locally different fracture surface contact, which is difficult to access during experiments. In this work, plasticity-induced crack closure under constant amplitude loading of an AlCu4Mg (AA2024) aluminium sheet material is studied from a three-dimensional perspective. An elastic–plastic 3D finite element model of an M(T)160 specimen with a bilinear isotropic hardening model is used to study the evolution of plasticity during fatigue crack growth. Cyclic crack propagation is simulated with the releasing-constraint method.In the results, plasticity-induced crack closure is present up to a load ratio R = 0.3. Detailed investigations of the contact pressure distributions indicate a strong dependence on the stress intensity factors and the sheet thicknesses. The contact pressure distributions on the fracture surface can be divided into three characteristic regions. Near the plastic zone, plastic energy is still induced during the unloading process after the crack is already closed. However, the crack surface contact does not affect the shape of the plastic zone. Additionally, further plastic energy accumulates in the plastic wake region during crack closure within subsequent load cycles, described here as cyclic plastic wake. In summary, the finite element model can reproduce the major features of fatigue crack closure like Kop or Kcl and the three-dimensional and load-dependent evolution of plasticity-induced crack closure.

Organization of interaction of various modes of transport in the production and transport processes of production and delivery of non-metallic construction materials

Production and transport processes for the delivery of non-metallic construction materials begin, as a rule, at flooded or overland quarries, and end at the consumer. The article considers the features of production and transport processes of extraction, transportation, unloading and shipment of non-ferrous building materials of channel mining to adjacent modes of transport on the example of enterprises of the Ob basin. The factors determining the efficiency of interaction of various modes of transport in multimodal transport hubs are revealed. On the example of one of the largest river enterprises of the Ob basin – JSC "Tomsk Shipping Company", the analysis of the operational performance of the fleet, the duration of round trips was carried out, the points with the greatest ship downtime were identified, and the value of specific downtime was calculated based on 1000 tons of transported cargo. The solution of the problem of coordinating the interaction of river and road transport is given on the example of unloading crushed stone in the river port of Nizhnevartovsk, considering the available storage areas.

Simulation of seismic velocity changes in brittle rocks subjected to triaxial stresses using 3-D microstructural models

SUMMARY Numerical simulation of non-linear elastic wave propagation in rocks is indispensable for understanding stress/damage dependence of wave velocity changes and the associated micromechanisms. A numerical microstructural model is presented here to investigate seismic velocity changes due to stress and damage. By introducing pre-existing cracks and considering the valid microstructures in the bonded particle model, the proposed method successfully reproduces velocity changes of experiments on dry Lac du Bonnet granite and dry Darley Dale sandstone in both loading and unloading processes. Velocity increasing results from the closure of pre-existing cracks during loading stages, while the reopen of cracks during the unloading process causes velocity decreasing. Particle velocity vectors are used to illustrate wave propagation in a micromechanical way. P wave wave fronts are observed from the source to travel through the model, and wave intersections are clearly shown in the medium when the tensile wave front meets the compressive wave. The microstructure of the model shows a significant effect on rock mechanical behaviour and velocities and lends credibility to the velocity simulation. The valid microstructure produces realistic mechanical behaviour and velocity changes. Also, it replicates the initial hardening in the axial stress versus the axial strain curve, while invalid microstructures (e.g. cement overlap) underestimate the elastic modulus. The simulations also show that the wave velocities scale with the square root of the corresponding component of the coordination number, which can be used to quantify the mechanisms behind the velocity changes. Direct relations were established between velocity changes and opened crack density, which displays a similar tendency compared with predictions of the effective elastic theory. The microstructural model provides the ability to simulate the macro behaviour of rock under loadings in a more realistic manner and to directly examine the microprocesses underlying velocity changes.

Experimental Analysis of Mass Exchange Across a Heterogeneity Interface: Role of Counter‐Current Transport and Non‐Linear Diffusion

AbstractSolute transport in heterogeneous and fractured systems is a complex process given the permeability contrasts and the time scales discrepancies of transport in high‐permeability versus low‐permeability regions. We studied this phenomenon by injecting a solute (dyed water) in a micromodel comprising a single channel in contact with a porous medium and evaluated the mass exchange across the interface between the channel and porous medium (resembling the interface between free flow and porous media regions). Two sets of transport experiments were performed at three injection rates of 0.01, 0.1, and 1 ml/hr. Injection of dyed water into a clean‐water‐filled micromodel (referred to as the loading process hereafter) and injection of clean water into a dyed‐water‐filled micromodel (referred to as the unloading process hereafter). The dynamics of solute transport was recorded using time‐lapse optical imaging. Our experimental results demonstrated the change of the mass exchange rate coefficient with time and a much smaller transfer rate coefficient during the unloading compared to the loading process. It is proposed that concentration‐dependent counter‐current advection‐diffusion cause slow‐down and further delay in the transport. These results may provide further explanation for the observed slow release of contamination in aquifers.

Effect of mixed plastic hardening on the cyclic contact between a sphere and a rigid flat

This paper studies the effect of mixed plasticity mode (combined with isotropic and kinematic hardening law) on the cyclic contact between an elastic-plastic sphere and a rigid flat. Assuming power-law hardening with different levels of mixed plasticity for the sphere, we derived a semi-analytical expression of load versus interference during the first loading and unloading process. During cyclic loading, our results indicate that the isotropic plasticity model shows no variation of residual interference, while kinematic plasticity has the cyclic effect on the residual interference, and this effect is bigger for the material with a higher hardening exponent. In addition, we provided the semi-analytical expression for the evolution of residual interference, which is accurate for the strain hardening exponent from 0.1 to 0.5.

Characterization of arching effect and failure mode of longwall panel floor

The stress arching mechanism of longwall panel floor were studied by theoretical analysis, numerical simulation and field observation. The study results show that: the direction of the principal stress on the floor is deflected in the process of mining, so the concentrated stress of floor transmits along an arching line. The goaf floor went through a process of high unloading, which intensifies the degree of crack propagation and fracture of the floor. Microcracks in floor are likely to connect with each other to form a macroscopic fracture surface, which leads to a significant volume expansion of goaf floor. There is a terrace-like tensile plastic zone in the goaf floor and an arched shear failure zone exists outside the tensile plastic zone. Field monitoring results reveal that the goaf floor is dominated by unloading tensile failure, and the floor in front of the mining face is dominated by shear failure.

Gas Seepage Model and Experiment Based on Bedding Effect of Fractured Coal Body

Gas drainage is of great significance for the efficient and safe mining in coal mine, in which the coal seam layer bedding has a great influence on it. For obtaining gas permeability characteristics of coal body with the parallel and vertical bedding in fractured coal under the action of stress loading and unloading, experimental research was carried out employing a three-stress-axis simulation device. Experimental results showed that in the stress loading process, the permeability decreased with increasing effective stress; the decrement was initially rapid albeit it slowed later. With the increase of effective stress, the coal sample underwent three stages, namely, crack compaction, elastic deformation, and plastic deformation. In the stress unloading process, the permeability of coal samples increased with decreasing of effective stress, and the increasing trend of permeability was consistent. The degree of fracture compaction of the parallel bedding coal samples after compression was much higher than that of vertical bedding. In the stress-relieved coal seam, gas drainage boreholes should be arranged vertically to the bedding fissure to maximise the gas drainage effect. A group of parallel and vertical bedding gas drainage holes were arranged in the test mine to investigate the drainage effect. Field engineering application also showed that the drilling direction should be perpendicular to the bedding direction as far as possible, so as to improve the gas drainage effect. The research results can provide a reference for the gas drainage borehole layout, thus maximising the gas extraction efficiency and ensuring the sustainability of mine safety production.