Static Friction in Oil Lubricated Cold Forming Processes

Friction is one of the variables that have a far-reaching influence on forming processes. In the past, less attention was paid to static friction than to sliding friction in forming processes. In this paper, a test stand for the determination of static friction under load in metal forming is presented. The results are discussed using the example of an oscillating cold forming process. It could be shown that the expected influence of static friction is low in this application. Graphical abstract

G-Force Test Stand for the Evaluation of Weapon Component Strength

This paper discusses the design of a G-force test stand intended to examine of the effects of mechanical loads present during firing of a weapon and applied to the electronic components contained in the 155 mm calibre guided projectile. The G-force test stand is used to develop and test the effects of using high mechanical loads by decelerating a test specimen through the use of a purpose-designed fender assembly. For the purpose of testing, it is irrelevant whether a load is developed by acceleration or deceleration of the test specimen, as a test result obtained by the deceleration of a test specimen is equivalent to a test result obtained by the acceleration of a test specimen, as used in a 155 mm calibre artillery guided projectile. The G-force test stand was used to test and determine the velocities developed by the test specimens and the G-forces applied to them. The maximum velocity to which a test specimen was accelerated was approx. 72 m/s. The test stand was able to propel the test specimens to velocities an order of magnitude higher than the velocities obtained with a Kast and Masset ram. The tests were performed with rubber and copper fender assemblies. The effect of the specific fender used was demonstrated on the trend of the generated G-force. The test stand could develop G-forces in excess of 10,000 with a duration of more than 500 µs.

Tests of a SI engine powered by gaseous fuels blends of LPG + DME of various proportions with variable load

The article presents the test stand and the test results of a vehicle with an SI engine, fueled by a blends of LPG and DME gaseous fuels. During the tests, a chassis dynamometer was used, which reproducibly reflected road conditions. The tests were carried out for various shares of DME in the mixture, thus determining the maximum possible share of this fuel. The measuring points have been extended with different engine loads and different rotational speeds. The analysis of the pressure inside the engine cylinder made it possible to compare the operation of the engine powered by mixtures of different proportions to the reference fuel - LPG.

Simulation research of the strength of an engine mount in an aircraft piston diesel engine

The article presents strength simulations of a mount for mounting the test engine. Mounted on a stationary test stand, this mount consists of external fixings, fixings to stabilize the engine and tubular elements as a truss. These tubular elements are pipes made of seamless black steel. The material of the truss is S235JR steel. The article examines three different versions of the mount: mount no. 1 - initial mount, mount no. 2 - mount after a modification of pipe arrangement, mount no. 3 - mount after a modification of pipe wall thickness. For each version of the mount and subsequent calculation steps, the same boundary conditions and results legend were assumed. All calculations were made in Catia v5 in the Generative Structure Analysis module. To reflect the conditions prevailing during the engine operation on the test bench, the following conditions as mount load were adopted: gravity from the engine mass as 1000 N; engine thrust as 5000 N, and engine torque as 227 Nm. First, the model was pre-calculated to check the influence of mesh size on the obtained results. 2 mm parabolic tetrahedral elements were used in a computational grid. All subsequent steps of the mount modification showed a positive effect of reducing the maximum stress values or their mitigation as dispersion over a larger area. The changes made it possible to eliminate potentially dangerous areas of stress accumulation points. The material used has a strength several times greater than the stresses occurring in the tested elements. It was found that no further modifications to the mount are required and it is possible to use the created geometry on the test stand.

Test stand for pulsed jet actuator command and characterization

The paper presents a test stand for characterization of a new design of a Pulsed Jet Actuator. The aim of the work was to characterize the performance of the PJA in terms of air parameters in the air supply line and velocity at the PJA outlet. To perform a detailed characterization of the system performance, the test bench comprised: a pressure reductor, a mass flow rate controller, a mass flow rate meter, a pressure sensor, a fast pressure sensor, a flow temperature sensor and a Constant Temperature Anemometer. The PJA was commanded by a real time controller with Field Programmed Gate Array architecture. The experimental results show good agreement with the results of Computational Fluid Dynamics simulations performed at the design stage of the PJA. It has been found that the flow parameters at the PJA nozzle outlet match the design goals. The developed bench testing procedures will be used for silent conditions tests of the PJA system integrated into a leading edge of a wind tunnel model.

A Simple Brushless Motor and Propeller Test Stand for Experiment from Home

A brushless motor and propeller test stand is used to test brushless motors and propellers. This testing instrument is still only available in research laboratories. Students and researchers are unable to use laboratory facilities because of the Covid-19 epidemic, thus students must be able to do tests independently from home. Purchasing this testing instrument would be too expensive for students. It is essential to construct a brushless motor and propeller testing instrument at home using simple components that are easy to get on the marketplace. The design concept reads force data using a loadcell sensor and an HX711 driver, and current and voltage data with an INA 219 sensor. The brushless motor’s rotational speed is controlled by a potentiometer. Force, current, voltage, and power are all examples of test results data. A 16×2 LCD is used to show data immediately. Data is also transmitted via a USB connection to a computer device for storage or additional analysis. This study proposes a simple brushless motor and propeller test stand that can measure forces from 0 gf to 1000 gf with an error rate of 0.72 %. The power that can be read ranges from 0 mW to 18960 mW, with a 0.59 % error rate.