RESEARCH OF SEED GROUP STRUCTURE CHARACTERISTICS OF VERTICAL DISC METERING DEVICE BASED ON DISCRETE ELEMENT METHOD

The vertical disc seed metering device was selected to study the influence of the structural characteristics of seed group on the filling performance of seed metering device. The working process of seed metering device was simulated by discrete element software to study the influence of seed quantity and structure characteristics of seed chamber on seed movement and filling results. The seed group was divided into four zones: ascending zone, relative static zone, collapse zone and recirculation zone. The number of seeds and the rotation speed of disk have no effect on the inclination angle of the recirculation zone upper surface, which was always about 35°. But they had a significant effect on the filling performance. When the number of seeds was 500-1500, QFI (quality of feed index) decreased, MIS (miss index) increased and MUL (multiple index) did not change significantly. However, when the number of seeds was 2000, the change trend of filling performance was completely opposite. Inner surface inclination angle and axial width of the seed chamber have significant effects on the filling performance. QFI first increased and then decreased with the increase of inclination angle, reaching the maximum at 20° and MIS showed the opposite trend. QFI increases with the increase of thickness and tends to be stable at 40mm. Similarly, MIS has the opposite trend.

Damping Impact on 1-Dimensional Ultrasonic Vibration-Assisted Turning Machining

In ultrasonic vibration-assisted turning (UVAT), vibration is one of the critical factors that causes noise during machining and affects cutting tool life, machining accuracy and workpiece surface quality. Vibration generated by piezoelectric actuators tends to transmit undesired vibration on the edge of the cutting tool and tool post. This situation hinders the maximization of vibration energy usage in the cutting tool. Thus, this paper investigated the vibration performance in the cutting tool by adding an isolator pad as damping element in the static zone of a tool holder to reduce the resonance generated during the machining process. The static, vibration and surface roughness analysis has been performed to determine the impact of damping on the machining performance. The results revealed a significant improvement in surface roughness where the best Ra for UVAT was 0.38 μm. In addition, vibration and static analysis showed the application of isolator pad capable of reducing 80% of energy loses and a supporter to increase the displacement, respectively. Ultimately this innovative solution can play an important role in improving UVAT performance.

Damping Impact on 1-Dimensional Ultrasonic Vibration-Assisted Turning Machining

In ultrasonic vibration-assisted turning (UVAT), vibration is one of the critical factors that causes noise during machining and affects cutting tool life, machining accuracy and workpiece surface quality. Vibration generated by piezoelectric actuators tends to transmit undesired vibration on the edge of the cutting tool and tool post. This situation hinders the maximization of vibration energy usage in the cutting tool. Thus, this paper investigated the vibration performance in the cutting tool by adding an isolator pad as damping element in the static zone of a tool holder to reduce the resonance generated during the machining process. The static, vibration and surface roughness analysis has been performed to determine the impact of damping on the machining performance. The results revealed a significant improvement in surface roughness where the best Ra for UVAT was 0.38 μm. In addition, vibration and static analysis showed the application of isolator pad capable of reducing 80% of energy loses and a supporter to increase the displacement, respectively. Ultimately this innovative solution can play an important role in improving UVAT performance.

Smart Radar Glasses

The aim of the project is to help differently able person, especially blind or visually impaired people, who are unable to recognize the object which is coming towards them. When a visually impaired person navigates into the heavy traffic area, it is difficult for them to cross the street. The outcome of the project is to give a signal to the visually impaired person, so that he/she can be able to keep themselves in a safe/static zone and is easy to use for the visually impaired person. In this project we use glass sensors having an accurate and precise sensor (VL53L1X) which is based on the LIDAR which will calculate the distance between objects or hurdles in front of blind person and respond. For response we have use a vibrating mini motor which will alert the blind person by giving vibrating alert. A vibration will be produced in accordance with the distance. Nearer the object, faster will be the vibration and far the object, slower will be the vibration. We have tried to make a user friendly and handy equipment by using a power supply of 3.7V battery, which is rechargeable, compact in size and easy to use by the user. An Arduino Nano is being used to reduce complexity of circuit and to produce the required output.

Investigation of Bearing Strength of Single-Bolt Double-Lap Joints in Composite Laminate

Based on the Upper Bound Theory, a Simplified Engineering Approach is Presented to Determine the Ultimate Strength of a pin-Loaded Composite Laminate in this Papaer. According to the Upper Bound Theory, the Displacement Rate in a Given Ply is Divided into Two Zones: the Moving Zone and the Static Zone. the Applied Load Q that Associated with Displacement must be Less than the Maximum Resistance of the Laminate. in this Paper we have Discussed the Failure Region, Failure Type of each Ply and Simplified the Tsai-Wu Failure Criterion. Experiments of Single-Bolt Double-Lap Joints have been Conduncted According to ASTM D5961 Test Standard. Finally, we can Observe that the Engineering Approach is in Good Agreement with the Test Results.

Analysis of Particle Trajectory within Rotating Cylinders by DEM Simulation

Particle trajectory within rotating cylinders has been investigated in terms of radial positions by using the discrete element method (DEM). The dynamic information of particle groups has been obtained under a wide range of rotation speed by a method of particle marking and tracking. The results show a periodic way of inwards trend for particle motion within material bed. The period of particle motion is directly related to the rotation speed of the cylinder. However, the residence time of particles in the active layer shortens with periods, while that in the static zone prolongs. Moreover, the peak value of radial positions periodically decays, whereas the valley value periodically increases. This research laid a good foundation for further research on particle mixing and heat transport within the material bed in rotating cylinders.

Solids Flow Models for Gas - Flowing Solids - Fixed Bed Contactors

Three solids flow models for gas – flowing solids – fixed bed contactors are analyzed. They all presume axial dispersion in the dynamic, freely flowing zone, but they differ in the interpretation of the stagnant zone. The models have been examined and the model parameters have been optimized on the basis of two types of tracer experiments. One provides step response curves for flowing solids at the exit and the other presents the response curves of the static flowing solids holdup. The model which assumes axial dispersion and exchange between dynamic and two active static zones, most accurately describes the solids flow pattern. A simpler model which presumes exchange between dynamic and one static zone can be used if there is no need for a precise description of the behavior of stagnant particles. The most simple axial dispersion model is not realistic, as it does not explain stagnancy at all, which was experimentally observed for the gas – flowing solids – fixed bed contactors.

Imaging quasi‐layered conductive structures by simple processing of transient electromagnetic data

An “imaged” conductivity section of a layered earth can be obtained by simple transformation of step‐response electromagnetic data measured in the quasi‐static zone. This method of data transformation is presented as an alternative to conventional apparent conductivity transformations. At each delay time, the variation of the step response as a function of geometry (transmitter and receiver location) is transformed to an equivalent reference depth h, which can be related to the depth of electromagnetic field diffusion. The behavior of h as a function of delay time is nearly independent of the source‐receiver geometry. The slowness dt/dh divided by the magnetic permeability is almost exactly proportional to the cumulative conductance measured from the surface down to a depth h. Thus we can estimate an apparent conductivity, which we call the “imaged conductivity,” at depth to be [Formula: see text]. The cost of this transformation is a fraction of the cost of conventional data inversion, and it does not require an a priori constraint on the number of parameters used in the inversion. The empirically developed technique was used successfully to process UTEM field data measured over a quasi‐layered earth.

Behaviour of a sensitive clay during pile driving

A full scale investigation with six instrumented test piles has been carried out on the Saint-Alban test site in order to study the behaviour of friction piles in soft sensitive soils. The first part of this investigation, reported in this paper, deals essentially with the effects of pile driving on the induced pore pressures and their dissipation and on the disturbance of the clay around the pile.It is shown that the induced pore pressures at the pile tip ΔuT, and at the pile surface Δus, correspond to 1.6σvo and 0.8σvo respectively. If the failure pattern developed during driving is interpreted by means of the theories of expansion of cavities, it is shown that the induced pore pressures calculated at the pile–soil contact agree well with the measured values; these pore pressures are fully dissipated after 600 h.Immediately after driving, a decrease in the undrained shear strength varying between 0 and 30% was observed in a zone of 3 diameters around the pile. The strength in that zone was nearly fully recovered after the pore pressures had dissipated.The tip resistance measured during driving was quite in excess of the static zone penetration resistance qc, indicating possible scale effects. The average unit skin friction was observed to decrease from a value in the order of cu to about 0.10σvo′ and to be directly related to the pore pressures, i.e., to the effective stresses in the clay around the pile.