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Dimensional and profile measurements of deep-hole parts are key processes both in manufacturing and product lifecycle management. Due to the particularity of the space conditions of deep-hole parts, the existing measurement instruments and methods exhibit some limitations. Based on the multi-axis, highly precise servo drive system, a novel measuring device is developed. The laser displacement sensors are fed by the flux-switching permanent magnet linear motor, and the part is rotated by the servo motor. On this basis, the assessment methods of roundness, straightness, and cylindricity are proposed by employing the least square method (LSM). Additionally, considering the axial center deviation between the sensors and the part, the rotating center coordinate is optimized by the gradient descent algorithm (GDM). Then, the measurement system is constructed and the experiment study is conducted. The results indicate favorable evaluation error of the LSM fitting and GDM iteration. Compared with the coordinate measuring machine (CMM), the measured results show good consistency. In the error analysis, the angle positioning error of measured point is less than 0.01°, and the axial positioning error is less than 0.05 mm. The proposed system and assessment method are regarded as a feasible and promising solution for deep-hole part measurements. [ABSTRACT FROM AUTHOR]

In order to find the optimum climb parameters for decreasing aircraft pollution emissions, we establish a calculation model of aircraft pollutant emissions to thoroughly examine the economy of aircraft operation and its impact on the environment, based on the International Civil Aviation Organization reference emission data and Boeing Method 2 which can calculate pollutant emissions in different flight phases by correcting the ICAO emission data. Firstly, we propose the concept of integrated flight cost considering the effect of emissions and establish its calculation model. Secondly, we establish the climb speed optimization models based on the traditional flight cost and integrated flight cost. Then, we analyze the effect of climb performance on the integrated flight cost. Next, we establish a combined optimization model of indicated airspeed and thrust using the genetic algorithm. The model simulation and result analysis are carried out using a wide-body aircraft. Finally, we analyze the effect of the optimization parameters and the sensitivity of the pollution index. The results show that the decrease in the flight speed and thrust effectively reduces the cost of pollutant emission during flight. The combination of (Vc, Tr) with the smallest integrated flight cost reduces the integrated flight cost by 1.28% and emission cost by 4.56%.

In order to develop reliable constitutive equations for the simulation, the hot deformation behavior of FV520B steel was investigated through isothermal compression tests in a wide range of temperatures from 900 °C to 1100 °C at an interval of 50 °C and strain rate from 0.01 to 10 s−1 on Gleeble-1500D simulator. The effects of temperature and strain rate on deformation behavior were represented by Zener-Holloman parameter in an exponent-type equation of Arrhenius constitutive. The influence of strain was incorporated in the constitutive analysis by material constants expressed as a polynomial function of strain. The constitutive equation (considering the compensation of strain) could precisely predict the flow stress only at strain rate 0.01 s−1 except at the temperatures of 900 °C and 1000 °C, whereas the flow stress predicted by a modified equation (incorporating both the strain and strain rate) demonstrated a well agreement with the experimental data throughout the entire range of temperatures and strain rates. Correlation coefficient (R) of 0.988 and average absolute relative error (AARE) of 5.7% verified the validity of developed equation from statistical analysis, which further confirmed that the modified constitutive equation could accurately predict the flow stress of FV520B steel.

Due to the poor processability of 0Cr17Ni4Cu4Nb stainless steel, the inserts are quickly worn down during the cutting process, affecting both the machining accuracy and surface quality of the machined part. In this study, the wear performance of four different types of coated inserts, TiCN+Al2O3, TiAlN, multilayer Ti composite, and TiCN+Al2O3+TiN, were investigated on the external turning of 0Cr17Ni4Cu4Nb stainless steel. The effects of different coatings on insert durability were analyzed from the perspective of wear profile, flank wear, and chip morphology. The wear of the inserts was mainly resulted from abrasive wear, diffusion wear, and adhesive wear. The flank wear ranking from the lowest to the highest for four coated inserts was TiAlN coating, TiCN+Al2O3 coating, TiCN+Al2O3+TiN coating, and multilayer Ti composite coating. The TiAlN coating deposited by physical vapor deposition exhibited excellent high-temperature oxidation resistance and stability, indicating its suitability for the turning of 0Cr17Ni4Cu4Nb stainless steel component. This study provides not only an important guidance for choosing inserts with different coating materials to improve wear performance, but also a good reference on the optimal design of indexable coated inserts for different materials. [ABSTRACT FROM AUTHOR]

In recent years, mechanical clinching has been widely used to join aluminium alloy sheets to build the automotive body. The high protrusion on the joint may limit the use of the mechanical clinching in the visible places. In order to get a lower protrusion, a compressing method was investigated in this work. Clinched joints with different geometrical parameters were used to conduct the experiments. AL5052 was taken as the material of the sheets. The protrusion of the clinched joint was compressed by two flat dies. A rivet placed in the pit of the clinched joint was used to control the metal flow in the compressing process. The top die moved downward to compress the protrusion, and the bottom die was fixed. The study shows that the tension-shearing strength and cross-tensile strength can be increased by the compressing method. The compressing method can increase the tension-shearing strength and cross-tensile strength by increasing the neck thickness. The compressed joint has larger neck thickness and lower protrusion than the clinched joint. Neck fracture mode is the main failure mode of the joints. The energy absorption can also be increased after the compressing process. [ABSTRACT FROM AUTHOR]

A mechanical clinch–compress joining technology was investigated to join sheets with different thicknesses in the present study. A pair of flat dies was used to compress the clinched joint, and a rivet was used to increase the joining strength. Al5052 sheets with different thicknesses were used to conduct the joining experiments. Tensile strength test and shearing strength test were conducted to evaluate the quality of the compressed joint. Failure mode, feasibility of the joining method, neck thickness, tensile strength, shearing strength, and energy absorption were investigated to show the mechanical properties of the compressed joint. The main failure mode of the joints is neck fracture mode, which means that the neck thickness determines the strength in this study. The mechanical clinch–compress joining technology can increase the strength and energy absorption of the joint by increasing the neck thickness. The joint with a thick upper sheet also can get higher strength and energy absorption by producing a thicker neck thickness. The mechanical clinch–compress joining technology can be used in the visible areas where higher strength and lower protrusion are needed. [ABSTRACT FROM AUTHOR]