Effect of process parameters on stress and strain of hybrid deposition and micro-rolling

Purpose This paper aims to summarize the influence law of hybrid deposited and micro-rolling (HDMR) technology on the shaping strain and residual stress. And the rolling parameters combination was further optimized to guide the actual production. Design/methodology/approach This paper proposed a three-dimensional coupled thermo-mechanical model of the HDMR process. The validated model is used to investigate the influences of rolling parameters on stress and plastic strain (the distance between the energy source and roller [De–r], the rolling compression [cr] and the friction coefficient [fr]). The orthogonal optimization of three factors and three levels was carried out. The influence of rolling parameters on the plastic strain and residual stress is analyzed. Findings The simulation results show that HDMR technology can effectively increase the shaping strain of the weld bead and reduce the residual tensile stress on the weld bead surface. Furthermore, the influence of rolling parameters on stress and strain is obtained by orthogonal analysis, and the corresponding optimal combination is proposed. Also, the rolling temperature significantly affects the residual stress, and the rolling reduction has a substantial effect on the plastic deformation. Research limitations/implications Owing to the choice of research methods, this paper failed to study microstructure evolution. Originality/value This paper provides a reference principle for the optimal selection of rolling parameters in HDMR.

Multi-objective optimization of muffler for vehicle air-conditioning compressor pipeline

The noise reduction of air-conditioning systems has gradually become an urgent problem with the comfortable requirement of driving, and the muffler is a commonly used noise reduction equipment for air-conditioning pipeline. In this article, the transmission loss of prototype muffler is co-simulated at different speeds. For optimizing the muffler, a new method that combines orthogonal optimization and detailed optimization is proposed. In orthogonal optimization, the multi-objectives orthogonal test is used to analyze the effect of four structural parameters (the shoulder height, the length of the cavity, the diameter of cavity, and the length of intubation) on the average transmission loss, the transmission loss at 1120Hz, and the frequency band width below 4dB. The influence of different factors on the transmission loss is studied at different speeds, and it found that the length of intubation has a significant impact on the transmission loss. In detailed optimization, the method is characterized by rapidity in the design of air conditioning system of vehicle, and the final optimization model is determined. The results show that the optimized structure is better than the original structure. The maximum reduction of average noise can reach 11.99dB, and the maximum noise reduction at 1120Hz reach 8.58dB.

Influence of automobile sealing rib structure on sound insulation performance and optimization of section parameters

The door sealing strip plays an important role in the sound insulation of the car, and its sound insulation performance has a great influence on the sound quality and comfort of the vehicle. The sound insulation performance of the seal can be analyzed by Finite Element-Statistic Energy Analysismodel. There are great differences in the cross-section of the door sealing strip system at different positions, which leads to the difference of sound insulation. Therefore, it is very important to study the sound insulation performance of the sealing strip by studying the parameters of different sections. This paper explores the influence of the structure of automobile sealing rib on the sound insulation performance. Taking the sound power of the receiving end of the sealing strip as the index, the orthogonal optimization test is carried out for the simplified section shape of the door seal strip: the wall thickness of the sealing strip, the height of the sealing strip and the rib length. The optimal combination of a set of sealing strip sections is established, and the sound insulation performance of the sealing strip is improved.

Application of a modified biological flocculant in total nitrogen treatment of leather wastewater

Leather wastewater harms the ecological environment and human health. In this study, a modified bio-flocculant was prepared to facilitate treatment of leather wastewater. A bio-flocculant produced by Bacillus cereus was combined with amphoteric starch and modified using a cerium ammonium nitrate initiator. Single factor optimization and orthogonal optimization were used to determine the optimal preparation conditions as follows: amphoteric starch-to-flocculant ratio = 22:30; reaction temperature = 64 °C; initiator dosage = 2.00%; reaction time = 15 min; stirring speed = 600 rpm; and flocculation system pH = 8.0. At a dosage of 1 g/L added to simulated leather industry wastewater, the flocculation efficiency (98.17%) and the total nitrogen removal efficiency (100.00%) of modified bio-flocculant was superior to that achieved by 1 g/L of unmodified bio-flocculant (72.16% and 50.00%, respectively), amphoteric starch (8.50% and 0.00%) and polyacrylamide (95.55% and 75.00%). Analysis of natural and flocculated precipitates in the wastewater showed that the modified bio-flocculant significantly changed several characteristics of the flocculated particles; in addition, it promoted the removal of nitrogenous substances in the process of denitrification. These changes helped explain the material's flocculating ability. The results confirmed that the modified bio-flocculant was an effective additive for treating leather wastewater.

Extraction of Anthocyanin from Eggplant Peel by Ultrasonic Assisted Method and Application in Cosmetics

The anthocyanin of eggplant skin was extracted by ultrasonic assisted method. Single factor experiment and orthogonal optimization experiment were used to optimize the extraction factors of anthocyanin from eggplant peel. The results showed that the optimum extraction of anthocyanin from eggplant peel was obtained by orthogonal experiment under the condition of feed-liquid ratio of 13:15, time of 40 min, and temperature of 50ºC. The anthocyanin is stable by treating 1 min after 100ºC.