Load capacity of single-lap adhesive joints made of 2024-T3 aluminium alloy sheets after shot peening

The goal of the work reported was to determine the influence of selected shot peening parameters on the deflection of the Almen strip and the load capacity of single-lap adhesive joints made of 2-mm-thick aluminium alloy EN AW-2024-T3. Moreover, the research was aimed at checking the possibility of using the Almen strip deflection indicator to predict the load capacity of adhesive joints after shot peening. The analysis was carried out according to Hartley’s PS/DS-P:Ha3 plan. The input factors were the shot peening parameters: treatment time t (60–180 s), ball diameter dk (0.5–1.5 mm) and compressed air pressure p (0.3–0.5 MPa). It has been proved in this work that shot peening treatment of the outer surface of single-lap adhesive joints can be used to strengthen the joint. The maximum increase in the load capacity of the shot peened joints was 33.4%. It was observed that the load capacity of the joints decreases with an increase in the deflection of the Almen strip (in the assumed area of variability of technological parameters). Moreover, the results obtained indicate that the adoption of too intensive treatment, manifested in high values of deflection of the Almen strip, may weaken single-lap adhesive joints.

The design of the sampling parameters for CMM of free-form surfaces

In order to improve the inspection accuracy of free-form surface by CMM, this paper adopted the different sampling parameters to research the influence of the measurement accuracy of free-form surface. Through the combination of area uniform block random sampling and Latin hypercube random sampling, the minimum sampling grid block area and ball diameter were taken as the research parameters. Firstly, this research analysed theoretically the influence of measurement accuracy of free-form surface by different sampling parameters. Secondly, carrying out experiments verified the analytical results. Then, the influence of two groups of sampling parameters on the normal deviation of free-form surface could be acquired by analysing the experimental data. Finally, this research could obtain the result of normal deviation of free-form surface. The research results showed that the minimum block area of sampling and the diameter of measuring ball become smaller, and the profile error become larger when the number of measuring points were the same, the more it can reflect the actual contour of the free-form surface, which proves that the measurement accuracy is higher.

Influence of Semi-Random and Regular Shot Peening on Selected Surface Layer Properties of Aluminum Alloy

This paper attempts to compare regular shot peening (RSP) and semi-random shot peening (SRSP). A characteristic of the first method is that the peening elements hit the treated surface in sequence, with a regular distance maintained between the dimples. The other method (SRSP) is a controlled modification of the shot-peening process, which is random by nature. The shot-peening method used in this study differs from conventional shot peening (shot blasting and vibratory shot peening) in that it allows controlled and repeatable determination of the configuration and distribution of impacts exerted by the peening element on the workpiece surface, which makes the process more repeatable and easier to model. Specimens of EN-AW 7075 aluminum alloy were used for testing. The following variables were used in the experiments: ball diameter, impact energy, and distance between the dimples. Microhardness distribution in the surface layer, 2D surface roughness, and surface topography were analyzed. FEM simulations of the residual stress distribution in the surface layer were performed. It has been found that regular shot peening results in reduced surface roughness, while semi-random shot peening leads to higher surface layer hardening.

NUMERICAL STUDY OF HEAT TRANSFER ENHANCEMENT BY INSERTING DIFFERENT SIZE BALLS INSIDE TUBE

In this paper, the challenge is to increasing of the heat exchanger performance by placing different size balls inside the tubes. the development of previous studies to enhance relatively bad case of heat transfer where the inserting (a large ball and then a small ball) to collide the water molecules in the ball and generate turbulent flow (Reynolds number range from 50,000 to 350,000) and thus increase the thermal performance due to collision of particles with the inner casing of the tube and reduce the stagnation near the wall. The usefulness of small ball, after the big ball, is Reduce of gets wake flow. A simulation was made when changing the diameter ratio of big to small ball (Dr = 3, 4, 5). Also, the distance between the big ball and the small ball was changed (X = 2, 3, 5) mm. It was concluded that the best ball diameter ratio and best Distance is (Dr= D_b/D_sb = 5), (X = 3 mm), respectively. The pressure drop acts as a side effect of enhancement. Therefore, the method of equal pumping was adopted. The average thermal performance factor (TPF=1.178) of tube with insert the balls enhanced by 17.8% at (x=3mm) and (Dr=5) when compared with smooth tube.

Survei Penggunaan Protective Equipment In Sport (PES) dalam Upaya Preventif dan Kuratif Cedera pada Atlet Bola Besar KONI Kota Malang

In addition to being identical to the ball diameter sport as the means used, big ball sports are also identical to the character of body contact. Direct body contact activity among athletes does not escape sports injuries. The increase in sports injuries occurs because body contact means the importance of both preventive and curative actions. The use of protective equipment in sports is an easy way to anticipate minimizing or worsening sports injuries. The purpose of this study was to determine the use of protective equipment in sport as a preventive and curative effort for big soccer athletes of KONI Malang City. This study used a quantitative descriptive research design with a survey approach. The population of this research is big soccer athletes such as soccer, basketball, volleyball and futsal, KONI Malang City. Sampling using probability sampling technique, the type of stratified random sampling with a sample of 21. The study used a questionnaire instrument with a Likert scale. The collected data were analyzed by IBM SPSS 21.0 application with a mean of 101.0952 and a standard deviation of 17.97750. The results of data analysis show that the level of use of protective equipment in sport is categorized as very low 1 or 4.8 percent, low 5 or 23.8 percent, moderate 9 or 42.8 percent, good 6 or 28.6 percent, and very good 0. The results of the study concluded that athletes in the use of protective equipment in sports, sports injuries were in law category. Abstrak: Olahraga bola besar selain identik dengan media diameter bola sebagai sarana yang digunakan, olahraga ini juga identik dengan karakter body contact. Aktivitas body contact secara langsung diantara olahragawan tak luput terjadinya peristiwa cedera olahraga. Maraknya peristiwa cedera olahraga terjadi karena body contact mengartikan pentingnya tindak preventif maupun kuratif. Penggunaan sarana pelindung atau protective equipment in sport merupakan salah satu hal mudah antisipasi meminimalisir maupun memperparah cedera olahraga. Tujuan penelitian ini adalah mengetahui penggunaan protective equipment in sport sebagai upaya preventif dan kuratif atlet bola besar KONI Kota Malang. Penelitian ini menggunakan rancangan penelitian deskriptif kuantitatif dengan pendekatan survei. Populasi penelitian adalah atlet bola besar seperti sepakbola, bolabasket, bolavoli dan futsal KONI Kota Malang. Pengambilan sampel menggunakan teknik sampling probability sampling, jenis stratified random sampling dengan sampel 21. Penelitian menggunakan instrumen kuesioner dengan skala likert. Data terkumpul dianalisis aplikasi IBM SPSS 21.0 dengan mean 101,0952 dan standar deviasi 17,97750. Hasil analisis data menunjukan tingkat penggunaan protective equipment in sport yaitu dikategorikan sangat rendah 1 atau 4,8 persen, rendah 5 atau 23,8 persen, sedang 9 atau 42,8 persen, baik 6 atau 28,6 persen, dan sangat baik 0 . Hasil penelitian disimpulkan atlet dalam penggunaan protective equipment in sport cedera olahraga kategori kurang.

ADDITIONAL CHARACTERISTICS OF HYBRID COMPOSITES FOR FILLING TEETH UNDER LOCAL MOUNTING CLOCKS

For the rational use of materials, it is necessary to have data on their ability to resist deformation and destruction. In particular, in each case it is necessary to have information on the stiffness, strength and resistance to destruction of materials in the specified operating conditions of the elements. To determine such strength characteristics of the material, certain studies are carried out. According to the analysis of literature sources in the study of dental composites mainly determine the tensile strength (bending) and compression [2-10], because it is subjected to restore materials during their operation in the oral cavity. The purpose of the study is to conduct a comparative analysis of the strength of hybrid composites of domestic and imported production during their local loading: Latelux (Latus, Ukraine), TETRIC N-CERAM (Ivoclar Vivadent, Liechtenstein), CHARISMA CLASSIC (Kulzer, Germany). To conduct research, 10 samples of each dental polymer composite were made. Packaging and molding of the material into a specially designed form was performed in laboratory conditions at an air temperature of 18 210 C with their subsequent polymerization with a LED photopolymer lamp Bluephase 20i (G2) (Ivoclar Vivadent). Before the test, the samples were kept for 24 hours at a temperature of 370 C in saline. The samples were loaded on the SVR-5 installation using a ball indenter (ball diameter mm steel SHX15, modulus of elasticity GPa, Poisson's ratio) with a speed of 0.002 mm/s. The purpose of the study is to conduct a comparative analysis of the strength of hybrid composites of domestic and imported production during their local loading. According to the results of experimental studies on the load of PB fracture, the Charisma Classic composite (5.72 ± 0.16 kN) has the highest strength, Latelux (4.23 ± 0.53 kN) the lowest, and Tetric N-Ceram (5, 03 ± 0.71 kN) occupies an intermediate position. To move the indenter, we obtained the following order of materials (in ascending order): Latelux (0.94 ± 0.11 mm); Charisma Classic (1.02 ± 0.04 mm); Tetric N-Ceram (1.03 ± 0.17 mm).

Design and Production of a New Smaller Diameter Axial Bearing Subjected to High Wear Loads

In the steering system of a passenger car, one of the essential components is the tie rod, and the sub-assembly component is the inner tie rod, which is subject to static and dynamic bearing loads. These bearing loads are the key points to ensure the inner tie rod's performance and total lifetime. A significant drop in the inner tie rod's performance can cause uncomfortable driving conditions and noise during driving. Most of the designs are developed over-safe with bigger ball sizes to fulfill the defined requirements. On the other hand, over-safe design can cause higher prices. In this study, a new small diameter axial bearing system is developed subjected to high wear loads on the inner tie rod. Three design parameters are considered: press force, tempering method, and tempering temperature. A smaller ball diameter design is created during the development phase. After the manufacturing, the inner tie rods are tested concerning the wear test and setting behavior under the maximum loading test. Results have been compared with a bigger ball size design. By changing the production and assembly parameters, optimum assembly conditions have been defined. Functional measurements before and after testing have validated the new smaller ball diameter design for serial usage.

Mathematical Modelling of the Fruit-Stone Culture Seeds Calibration Process Using Flat Sieves

The paper provided describes a mathematical model of calibration process of fruit-stone culture seeds of cherry, sweet cherry, cherry-plum, apricot and almond using flat sieves with impact shock ball cleaners oscillating in the horizontal plane. It has been defined that the mathematical expectation of time of knocking out the fruit-stone from the sieve opening T ⌢ \mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown$}}\over T} is the minimum value of ratio of average time of complete ball motion cycle in space under sieve to the probability of knocking out the stone by a ball with the kinetic energy level of 2 Mj. The dependences of energy distribution density of ball on impact on the sieve have been obtained, based on which the intervals of ball cleaner parameters have been determined, i.e. the ball diameter D belongs to the interval 25–35 mm; the space height H under sorting sieve belongs to the interval 1.2D–1.4D mm; the value range for distance between rods t belongs to the interval 0.5D–0.7D mm. Using the method of golden section, the following parameters of ball cleaner were obtained: D = 33 mm, t = 23 mm, H = 40 mm. The parameters obtained provide mathematical expectation of time of knocking out the fruit-stone from the sieve opening T ⌢ \mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown$}}\over T} = 0.03 s. Consequently, the average ball velocity v ⌢ \mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown$}}\over v} is = 0.4 m∙s-1, and the average ball path is L ⌢ \mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown$}}\over L} = 0.006 m.

Analytical modeling of through depth strain induced by deep rolling

The material properties of the surface layer caused by deep rolling are closely related to the degree of strain hardening. It is of great significance to establish the prediction model of strain distribution to realize the surface strain control and improve the service performance of deep rolling parts. In this study, the analytical models of elastic-plastic strain based on the Hertz contact theory were established by two different methods. The accuracy of the analytical prediction model of elastic-plastic strain was examined by deep rolling simulation. Then, the influence of deep rolling parameters, such as rolling force, the ball diameter, and material on the elastic-plastic strain along the depth was studied and validated by the microhardness profiles along the depth. The results indicate that the analytical model established by the first method is more accurate, and the error between maximum elastic-plastic strain obtained by the first method and finite element (FE) simulation is 12.6%. The elastic-plastic strain along the depth increases with the increasing rolling force and decreases with the increasing ball diameter, and its effective depth increases with the increasing rolling force. The tungsten carbide ball generates more elastic-plastic strain than balls of the other two materials (silicon nitride and steel). In addition, the elastic-plastic strain profiles are in accordance with the change of microhardness along the depth. In a word, the model can be used to predict the strain distribution along the depth induced by deep rolling.