Constitutive and Fracture Modeling of Biaxially Oriented Polyethylene Terephthalate Film and Its Application to Polymer-Coated Sheet Metal Forming

Polyethylene terephthalate (PET) films produced by rolling and tentering have biaxial orientation and thus exhibit anisotropic mechanical properties such as yielding, hardening, and fracture. The anisotropy of film makes it difficult to analyze deformation and failures occurring during processing such as metal forming of polymer-coated sheet metals. In this work, the anisotropic yielding and hardening of the PET film were measured and an anisotropic constitutive model is developed to represent the anisotropic behavior. In addition, fracture limits of the PET film were measured using the Nakajima test. To describe anisotropic fracture behavior of the film, an anisotropic fracture criterion based on the strain energy density and the theory of isotropic equivalent material was proposed. For validation of the developed constitutive model and the fracture criterion, a deep drawing test of the PET-coated sheet metal was conducted. The film cracking predicted by the anisotropic fracture criterion agreed well with measurements.

Tendencies of export and import of steel industry products of Russia within 9 months of 2019

Structure of the Russian export and import of steel industry products presented by results of 9 months of 2019 operation. It was shown, that the total share of pig iron, ferroalloys and semi-products (40.3%) in the ferrous metals export from Russia is practically the same as the share of rolled products and steel pipes (39.4%), whereas the shares in the import structure were 7.7 and 75% accordingly. The share the far abroad countries in the Russian export and import of finished steel products (in natural terms) accounted for 80.6 and 28.7% accordingly, while the share of CIS countries – 19.4 and 71.3% accordingly. For 9 months of 2019 the Russian export of semi-products declined by 10.9% comparing with the analogue period of 2018 and accounted for 10.9 m tons. 54.6% of the total export shipping of semi-products were directed to Mexico, Turkey, Egypt and Taiwan. Within the nearest years the Russian export of semi-products and billets, in particular, will be effected by the further development of the semi-products production in in the countries of Middle East, Turkey, Vietnam and India. The domestic market remained to be more attractive for many Russian companies. For the 9 months of 2019, export of long and flat products accounted for 3 and 5.7 m tons accordingly, declining comparing with the analogue period of the previous year by 11 and 15.6% accordingly. Import of long and flat products decreased by 12 and 0.5%, accounting for 1.0 and 2.9 m tons accordingly. By the results of 9 months of 2019, import declined and export shipping of coated sheet increased. Taking into account the expansion of steel grades assortment by Russian plants, increase of capacities for production of sheet with different coatings, this tendency is likely to remain.

Evaluation and Modeling of Corrosion Rate of Selected Roofing Sheets Using Tetraoxosulphate (vi) Acid and Trioxonitrate (v) Acid as Simulated Acid Rain

The study focuses on the evaluation of the impact of acid rain on some common roofing sheets, including; Stone Coated, Galvanized, 0.55 m and 0.45 mm Long Span , Aluminum/Zinc sheet using simulated acid rain. The simulated acid rain was from four different molar concentrated H2SO4 and HNO3. The parameter used for the evaluation was a weight loss of the roofing sheet over the study period. Gravimetric analysis technique was adopted for the study. At the end of the study, the result obtained showed that for 1 mole solution H2SO4, 0.45 mm long Span recorded the lowest weight loss of 0.43 g, followed by Cameroon zinc with loss of 0.46 g while 0.55 mm long Span recorded 0.63 g. Stone-coated and galvanized sheet melted up before the end of the experiment. 1 mole solution of HNO3 recorded a similar trend with 0.46 g, 0.36 g, 0.47 g and 3.95 g weight loss for 0.55 mm long Span, Cameroon Zinc, 0.45 mm Long Span and stone Coated sheet respectively while Galvanized sheet melted up before the experiment ends. Stone Coated and Galvanized sheet melted up before the end of the experiment in 0.5 mole H2SO4 while 0.45 mm Long Span, 0.55 mm long span and Cameroon Zinc recorded 0.47 g, 0.5 g and 0.35 g weight loss respectively. Only Galvanized sheet melted up in 0.5 mole of HNO3, 3.5 g, 0.28 g, 0.38 g and 0.3 g weight loss was recorded for stone coated sheet, 0.45 mm long Span, 0.55 mm long Span and Cameroon Zinc respectively. Polynomial model of the fourth order show the best fit for the data. The models obtained for the weight loss and rate of corrosion showed a good fit with R2's ranging from 0.9 and above except for stone coated and galvanized sheets in 1 mole solution of H2SO4 with R2 of 0.782 and 0.8142. It is worthy to note from all the results obtained from the research that high percentage Aluminum base roofing sheet is the best for H2SO4 and HNO3 polluted environment.

PENGARUH TEMPERATUR TERHADAP RESISTANSI PADA THERMOELECTRIC GENERATOR TIPE SP 1848-27145 MODUL 5 SUSUNAN SERI KETIKA DIPANASKAN

One source of potential energy with new innovations, namely the use of thermoelectric generator. Utilization of thermoelectric generators as a Heat power plant requires further study or research to produce an optimal system so that it can be a source of electrical energy substitutes in the provision of electrical energy. The working principle of the heat power plant is the first thermoelectric generator heated by filament where between filament and thermoelectric generator coated sheet metal. If the temperature of the heated metal is greater than the temperature of the metal heat dissipation, then the temperature difference causes a thermoelectric generator starts to work optimally. Measurement of Thermoelectric Generator with model number SP 1848-27145 carried out a total of 11 experiments on different materials with the same method. It consists of 4 modules compiled series, saddled lamp dc 12 Volt, 5 Watt. Optimization for charging the accumulator is 12 volts dc with temperature 270C and with a current that is obtained is 3.01 Ampere.

Fatigue behavior of 590MPa Tensile Strength galvanneal coated sheet steel laser welded blanks

The use of Laser Welded Blanks (LWBs) with different grade/gauge combinations in automotive body structures is well established; however, the acceptance of LWBs in fatigue critical chassis and underbody components has been slower because of lack of reliable models for durability assessment of laser welded joints (LWJ). Most prior fatigue studies of LWBs are carried out in tension - tension loading mode, making it difficult to relate it to the cyclic deformation and fatigue behaviors of the substrate steel grade. In contrast, in this study, LWJ is conceptualized as a "notch" to estimate the local stresses from the strain - life data of the parent grade and the fatigue notch concentration factor (Kf) is estimated from the nominal stress values of LWJ. The method is illustrated with strain controlled fatigue data for 1.4 mm galvanneal coated 590 MPa steel and fully reversed, fatigue data for homogeneous and heterogeneous LWB combinations. The results indicate that for both homogeneous and heterogeneous LWJ configurations, Kf increases with fatigue life, but tends to saturate at life levels greater than about million cycles. Considering 105 cycles to failure as an example, Kf is estimated as 1.07 for the homogeneous and 1.25 for the heterogeneous combinations.