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- 3D Scanning (1)
- Axialspiel (1)
- Axialspielprüfgerät (1)
- Clean Waterjet Cutting (1)
- Gurtförderanlage (1)
- Measurement of Manufacturing Accuracy (1)
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В статье приведены результаты исследования производственных допусков при водоструйной резке методом трехмерных (3D) измерений: отклонения формы были показаны путем трехмерного справнения отсканированных образцов. Размеры были измерены также с использованием двухмерных (2D) срезов отсканированных образцов. Определено, что чистая водоструйная резка имеет тенденцию отделять мягкие материалы, такие как пластмасса, фольга, пена или бумага, а также пища. В отличие от чистой водоструйной резки, абразивная резка используется для твердых материалов, таких как сталь, керамика, стекло. Вычислено оптимальное давление для обработки материалов. Особое значение уделено разделению композитных материалов, которое не может быть удовлетворительно осуществлено с использованием обычных методов.
The Vibro Displacement Column (VDC) is one of the most widely-used techniques in
ground improvement. The present design of the column is exposed to high stresses from the soil during operation. There has been an increased fracture failure on basic parts of this VDC which has led to increase the downtime in construction projects. The major points of failures are identified and analyzed. Optimized design is presented after undergoing functionality experiments.
This paper investigates experimentally and numerically the aero-acoustic noise generated by airflow around sheet metals with periodic hills of three different geometries named KMT, PWO and WAB used in automotive industry.
Each sheet was tested experimentally in a wind tunnel at airflow of free-stream-velocity of 18 m/s and Reynold’s number based on the respective sheet thickness in the range of 1800-4200. The experiment was based on measuring the aero-dynamic sound generated by each sheet using a microphone. Moreover, it was based on measuring the velocity fluctuation after the sheets trailing edge by a Hot Wire Anemometer (HWA). Finally, an acoustic camera was used to locate the locations of sound sources in the flow. On the other hand, the numerical analysis used turbulence model as Large Eddy Simulation with Kinetic Energy Transport as a sub-grid model. Ffowcs-Williams & Hawkings model was used to predict the acoustic sources.
Agreements were found between the trend of acoustic noise
produced from experiment and numerical simulation over some
ranges of frequency. The experiment has showed that the three
sheets had comparable sound pressure level over the whole
spectrum while the numerical results have showed that KMT
sheet has achieved significant loudness at frequencies under 400
Hz while the WAB sheet has achieved significant quietness at
frequencies below 400 Hz. The velocity contours obtained from
the simulation showed that flow is laminar over some length
before it changes to turbulent at a transition point. This
behavior agrees with other data presented for long sheets
subjected to flow of similar values of Reynolds Number.
Umfassende Untersuchungen von Lagerausfällen bei Tragrollen mit einer Lagergröße ab über 6306 ergaben zu geringe Werte für das Axialspiel, welche sich als Schadensursache herausstellten. Da in der DIN 22112 Teil 2 lediglich Grenzwerte für die axiale Verschiebbarkeit für Tragrollen bis zu einer Lagergröße 6306 aufgeführt werden, war eine Bewertung von Tragrollen mit größeren Lagern im Sinne der Qualitätskontrolle bisher nicht möglich. Ausgehend von den Schadensbildern werden die theoretischen Zusammenhänge in Bezug auf den Lagerverschleiß erörtert. In Zusammenhang mit den wirkenden Belastungen auf die Tragrollen werden geeignete Grenzwerte für die axiale Verschiebbarkeit ausgearbeitet, welche die LEAG (Lausitz Energie Bergbau AG) in die aktuellen Lieferanforderungen für Tragrollen aufnahm. Weiterhin wird ein Axialspielprüfgerät vorgestellt, welches im Vergleich zu der vorgestellten Messeinrichtung aus der DIN 22112 Teil 3 präzisere Messergebnisse unabhängig von dem Achsgewicht der jeweiligen Tragrollen liefert.
This paper examines the surface roughness and power consumption of the machine when
using different inserts and cutting parameters in rough turning. For this purpose, the surface quality of the parts, cutting parameters at different levels (cutting speed, feed rate, depth of cut) and optimal tools that influence the energy when machining S355JR steel material of different cutting tools were used in the turning process.
Belt conveyors are highly efficient systems used in mining and other industries to transport bulk materials, mainly brown coal and overburden, over distances ranging from short distances to several kilometres. For technical reasons, their operation is associated with noise emissions. During inspections and maintenance this can lead to increased noise exposure of employees. In the vicinity of residential buildings or in areas needing protection, exceeding the emission limits can lead to a temporary restriction of the operation of these high performance installations. Measures are required to reduce the noise impact primarily at the source or in the immediate vicinity. The acoustic and mechanical parameters are investigated on a test bench at the Technical University of Brandenburg (BTU) Cottbus-Senftenberg as part of the drive assembly tests in cooperation with LEAG. The stages of these tests are: Run-up test. In this test the supporting roller is accelerated under test load to a circumferential speed of 10 m/s and the sound pressure level is recorded. This makes it possible to calculate the sound emission as a function of the peripheral speed; Recording the geometry of the idler gear. An accurate description of the geometry of the idler housing allows conclusions to be drawn about the possible causes of excitation. The defined characteristics serve to quantify the acoustic effect of the driven rollers and derive specifications for use in belt conveyor systems. Based on the special requirements to the planned belt conveyor system, an adapted selection of low-noise idler rollers can be made at an early stage on the basis of specified parameters and confirmed test results.