The concrete steps were as follows: firstly, a single variable was adjusted by manual control and the best parameter combination was determined through the comparison of 10 groups of data. Based on the preliminary optimization, the computer was used for automatic calculation and optimization. In this paper, by manually and automatically adjusting the structure of claw-flap PET carbonated beverage bottle bottoms, the cracking phenomenon of PET bottle bottoms due to stress concentration was effectively alleviated.Simple manual comparison is necessary, which can determine the optimal solution in a large range and reduce the number of operation groups in automatic optimization, thus, greatly shortening the operation time.Firstly, the variables were controlled manually for preliminary comparison and optimization. In fact, the structural design of the bottle bottom is also one of the important factors affecting the stress cracking of the PET bottle bottom. However, most of the above studies are about the characteristics of PET materials, without considering the geometric structure of products. focused on the effect of annealing before stretching on strain-induced crystallization of PET and found that treatment at 120 ☌ for 60 s would lead to amorphous phase relaxation and higher crystallinity, and with time, higher mechanical strength and smaller shrinkage would be obtained. The PET bottle blocked about 80% light transmission in a wavelength range of 400–700 nm and could be used in the food industry, especially in the packaging of dairy products, which are easily irradiated by light. used PET/nano hydroxyapatite (nHAp) composite particles to produce PET/nHAp bottles. In addition, the orientation and crystallinity of PET molecules are also the main factors that determine whether the mechanical properties of finished products are excellent. used Taguchi method (TM), Grey Relational Analysis (GRA), and ECHIP to analyze the effects of preform temperature, stretching rod position, and final pressure, and optimized the performance parameters. found that with the delay of pre-blowing pressure relative to the stretching effect, more materials would gather in the lower area of the final product by studying the influence of stretching and blow molding combination on the wall thickness distribution of 1.5Lt PET bottles. In terms of production technology, Lontos et al. In order to solve the cracking problem of the PET bottle bottom, scholars have conducted a great deal of research on the process of PET bottle injection molding and the characteristics of the material itself. This claw-flap-shaped PET bottle with complex bottom structure was prone to stress cracking. At present, the most commonly used carbonated beverage bottle was designed in the mid-1980s. PET has been widely used in the packaging of carbonated beverages because it can block CO 2 gas and retain the taste of soda water. Polyethylene terephthalate (PET) is an ideal container for food and beverage packaging, with properties of non-toxicity, light weight, high transparency, and impact resistance. The extremely high reduction ratio was caused by manual–automatic double optimization. Compared with the original bottle bottom, the total maximum principal stress and total elastic strain energy in the bottle bottom after manual–automatic double optimization decreased by 69.4% and 40.0%, respectively, and the displacement caused by deformation decreased by 0.60 mm (74.1%). Comsol software was used for automatic optimization. First, through manual optimization, the initial optimal parameter combination was as follows:the inner diameter of the bottle bottom was 17 mm, the dip angle of the valley bottom was 81°, the deepest part of the valley bottom was 25 mm, and the outer diameter was 27 mm. Because carbonated drinks contain large volumes of CO 2 gas, the container needs to bear a tremendous pressure from the inside of the bottle.If the stress exceeds the bearing limit, the material will show the phenomenon of local cracking and liquid overflow.For the structural design, the method of manual adjustment before automatic adjustment was adopted. PET bottlesare often used as airtight containers for filling carbonated drinks.
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