scholarly journals Analysis of the interactions between joint and component properties during clinching

Author(s):  
Christian Steinfelder ◽  
Johann Acksteiner ◽  
Christina Guilleaume ◽  
Alexander Brosius

AbstractClinching is a joining process that is becoming more and more important in industry due to the increasing use of multi-material designs. Despite the already widespread use of the process, there is still a need for research to understand the mechanisms and design of clinched joints. In contrast to the tool parameters, process and material disturbances have not yet been investigated to a relatively large extent. However, these also have a great influence on the properties and applicability of clinching. The effect of process disturbances on the clinched joint are investigated with numerical and experimental methods. The investigated process variations are the history of the sheets using the pre-hardening of the material, different sheet thicknesses, sheet arrangements and punch strokes. For the consideration of the material history, a specimen geometry for pre-stretching specimens in uniaxial tension is used, from which the pre-stretched secondary specimens are taken. A finite element model is set up for the numerical investigations. Suitable clinching tools are selected. With the simulation, selected process influences can be examined. The effort of the numerical investigations is considerably reduced with the help of a statistical experimental design according to Taguchi. To confirm the simulation results, experimental investigations of the clinch point geometry by using micrographs and the shear strength of the clinched joint are performed. The analysis of the influence of difference disturbance factors on the clinching process demonstrate the importance of the holistic view of the clinching process.

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2077
Author(s):  
Oliver Zeman ◽  
Michael Schwenn ◽  
Martin Granig ◽  
Konrad Bergmeister

The assessment of already installed anchorages for a possible exceeding of the service load level is a question that is gaining more and more importance, especially in building maintenance. Bonded anchors are of particular interest here, as the detection of a capacity reduction or load exceedance can cause damage to the concrete-bonded mortar behavior. This article investigates the extent to which ultrasonic methods can be used to make a prediction about the condition of anchorages in concrete and about their load history. A promising innovative assessment method has been developed. The challenges in carrying out the experimental investigations are the arrangement of the transducers, the design of the test set-up and the applicability of direct, indirect or semidirect ultrasonic transmission. The experimental investigations carried out on a test concrete mix and a bonded anchor system show that damage to the concrete structure can be detected by means of ultrasound. The results indicate the formation of cracks and therefore a weakening of the response determined by means of direct, indirect and semidirect ultrasonic transmission. However, for application under non-laboratory conditions and on anchors with unknown load history, the calibration with a reference anchor and the identification of the maximum load is required. This enables a referencing of the other loaded anchors to the unloaded conditions and allows an estimation of the load history of individual anchors.


Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 480 ◽  
Author(s):  
Bernd-Arno Behrens ◽  
Jörg Schröder ◽  
Dominik Brands ◽  
Lisa Scheunemann ◽  
Rainer Niekamp ◽  
...  

Residual stresses in components are a central issue in almost every manufacturing process, as they influence the performance of the final part. Regarding hot forming processes, there is a great potential for defining a targeted residual stress state, as many adjustment parameters, such as deformation state or temperature profile, are available that influence residual stresses. To ensure appropriate numerical modeling of residual stresses in hot forming processes, comprehensive material characterization and suitable multiscale Finite Element (FE) simulations are required. In this paper, experimental and numerical investigations of thermo-mechanically processed steel alloy 1.3505 (DIN 100Cr6) are presented that serve as a basis for further optimization of numerically modeled residual stresses. For this purpose, cylindrical upsetting tests at high temperature with subsequently cooling of the parts in the media air or water are carried out. Additionally, the process is simulated on the macroscale and compared to the results based on the experimental investigations. Therefore, the experimentally processed specimens are examined regarding the resulting microstructure, distortions, and residual stresses. For the investigation on a smaller scale, a numerical model is set up based on the state-data of the macroscopic simulation and experiments, simulating the transformation of the microstructure using phase-field theory and FE analysis on micro- and meso-scopic level.


2012 ◽  
Vol 12 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Kirsi Lehto ◽  
Harry J. Lehto ◽  
Ari Brozinski ◽  
Esko Gardner ◽  
Olav Eklund ◽  
...  

AbstractWith the aim to visualize the span of time since the formation of our Universe we have set up a nature and hiking trail called ‘Time Trek’. The 13.7 km length of the trail corresponds to the age of the Universe, and portrays its history including events important for Earth and life. One kilometre corresponds to a billion years, and one metre to a million years of time. The trek combines astronomical, physical, geological and biological time lines, and presents a holistic view of the history of time. It helps people to comprehend the causal and temporal connections of different phenomena. To the trekker, it offers a concrete experience of the lengths and proportions of different time periods, which otherwise are very difficult to understand.


2011 ◽  
Vol 101-102 ◽  
pp. 500-507
Author(s):  
Bin Hua Wang ◽  
Peng Min Lu ◽  
Yu Hong Shao

The motion equation of boom system of pump truck carrying concrete flow is set up based on the coupled vibration theory of cantilevered pipe and the finite element theory. Dynamic stress history of boom system with parameters of dip angle α=0°is simulated combining MATLAB simulation analyses with ANSYS finite element model. The feasibility of this method is verified through field experiment. Stress histories are simulated by adjusting parameter of dip angle as follows: α=20°,52°and 80°.Great stress points are painted on the Goodman Fatigue Limit Diagram measured by experiment. And then fatigue strength assessment of boom system is done. The research method can be used for the design calculation of similar products.


2014 ◽  
Vol 4 (3) ◽  
pp. 95-98
Author(s):  
Iana Proskurkina

Abstract The growing number of foreign applicants looking forward to getting education in Ukrainian medical universities makes us find the ways how to improve and make effective the pre-professional training system of foreign medical applicants for further education. The article deals with the issues of the history of formation and development of the preprofessional training system of foreign medical applicants in Ukraine. On the ground of the electronic databases of the official websites of higher educational establishments, the data on years of opening first offices of the dean, departments and preparatory faculties for foreign medical applicants in Ukrainian medical universities are analyzed and systematized. Also the data on the setting up preparatory faculties at other universities who carry out licensed training of foreign students of the medical profile are presented. The data on the operating and management of such institutions in the system of the University administration are generalized. It’s revealed that during the years of its functioning the pre-professional training has changed, in particular the system was commercialized and the institutions involved in training foreign applicants have been reorganized. The modern trends in teaching foreign medical students at the preparatory faculties of the Ukrainian medical universities are displayed. Based on the analysis of the data it is concluded that the system of the pre-professional training of foreign medical applicants was set up in the 50s-60s years of the twentieth century. During this time, some positive experience in the preparation of future international medical specialists has been gained. The system of the pre-professional training of foreign medical applicants has been comprehensively improved and an effective system of managing foreign medical applicants has been created.


2019 ◽  
pp. 134-197
Author(s):  
V.E. . Sergei

The article is dedicated to the history of the Military Historical Museum of Artillery, Engineering and Signal Corps. The author examines the main stages of the museums formation, starting with the foundation of the Arsenal, established in St. Petersburg at the orders of Peter the Great on August 29th 1703 for the safekeeping and preservation of memory, for eternal glory of unique arms and military trophies. In 1756, on the base of the Arsenals collection, the General Inspector of Artillery Count P.I. created the Memorial Hall, set up at the Arsenal, on St. Petersburgs Liteyny Avenue. By the end of the 18th century the collection included over 6,000 exhibits. In 1868 the Memorial Hall was transferred to the New Arsenal, at the Crownwork of the Petropavlovsky Fortress, and renamed the Artillery Museum (since 1903 the Artillery Historical Museum). A large part of the credit for the development and popularization of the collection must be given to the historian N.E. Brandenburg, the man rightly considered the founder of Russias military museums, who was the chief curator from 1872 to 1903. During the Civil and Great Patriotic Wars a significant part of the museums holdings were evacuated to Yaroslavl and Novosibirsk. Thanks to the undying devotion of the museums staff, it not only survived, but increased its collection. In the 1960s over 100,000 exhibits were transferred from the holdings of the Central Historical Museum of Military Engineering and the Military Signal Corps Museum. In 1991 the collection also received the entire Museum of General Field Marshal M.I. Kutuzov, transferred from the Polish town of Bolesawjec. The Military Historical Museum of Artillery, Engineering and Signal Coprs is now one of the largest museums of military history in the world. It holds an invaluable collection of artillery and ammunition, of firearms and cold steel arms, military engineering and signal technology, military banners, uniforms, a rich collection of paintings and graphic works, orders and medals, as well as extensive archives, all dedicated to the history of Russian artillery and the feats of our nations defenders.Статья посвящена истории создания ВоенноИсторического музея артиллерии, инженерных войск и войск связи. Автор рассматривает основные этапы становления музея, начиная с основания Арсенала, созданного в СанктПетербурге по приказу Петра I 29 августа 1703 года для хранения и сохранения памяти, во имя вечной славы уникального оружия и военных трофеев. В 1756 году на базе коллекции Арсенала генеральный инспектор артиллерии граф П. И. создал мемориальный зал, установленный при Арсенале, на Литейном проспекте СанктПетербурга. К концу 18 века коллекция насчитывала более 6000 экспонатов. В 1868 году Мемориальный зал был перенесен в Новый Арсенал, на венец Петропавловской крепости, и переименован в Артиллерийский музей (с 1903 года Артиллерийский Исторический музей). Большая заслуга в развитии и популяризации коллекции принадлежит историку Н.Е. Бранденбургу, человеку, по праву считавшемуся основателем российских военных музеев, который был главным хранителем с 1872 по 1903 год. В годы Гражданской и Великой Отечественной войн значительная часть фондов музея была эвакуирована в Ярославль и Новосибирск. Благодаря неусыпной преданности сотрудников музея, он не только сохранился, но и пополнил свою коллекцию. В 1960х годах более 100 000 экспонатов были переданы из фондов Центрального исторического военноинженерного музея и Музея войск связи. В 1991 году коллекцию также получил весь музей генералфельдмаршала М. И. Кутузова, переданный из польского города Болеславец. Военноисторический музей артиллерии, инженерных войск и войск связи в настоящее время является одним из крупнейших музеев военной истории в мире. Здесь хранится бесценная коллекция артиллерии и боеприпасов, огнестрельного и холодного оружия, военной техники и сигнальной техники, военных знамен, обмундирования, богатая коллекция живописных и графических работ, орденов и медалей, а также обширные архивы, посвященные истории русской артиллерии и подвигам защитников нашего народа.


2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2547
Author(s):  
Elena Garcia ◽  
Julio Torres ◽  
Nuria Rebolledo ◽  
Raul Arrabal ◽  
Javier Sanchez

Reinforced concrete may corrode in anoxic environments such as offshore structures. Under such conditions the reinforcement fails to passivate completely, irrespective of chloride content, and the corrosion taking place locally induces the growth of discrete pits. This study characterised such pits and simulated their growth from experimentally determined electrochemical parameters. Pit morphology was assessed with an optical profilometer. A finite element model was developed to simulate pit growth based on electrochemical parameters for different cathode areas. The model was able to predict long-term pit growth by deformed geometry set up. Simulations showed that pit growth-related corrosion tends to maximise as cathode area declines, which lower the pitting factor. The mechanical strength developed by the passive and prestressed rebar throughout its service life was also estimated. Passive rebar strength may drop by nearly 20% over 100 years, whilst in the presence of cracking from the base of the pit steel strength may decline by over 40%.


2013 ◽  
Vol 456 ◽  
pp. 576-581 ◽  
Author(s):  
Li Fu Xu ◽  
Na Ta ◽  
Zhu Shi Rao ◽  
Jia Bin Tian

A 2-D finite element model of human cochlea is established in this paper. This model includes the structure of oval window, round window, basilar membrane and cochlear duct which is filled with fluid. The basilar membrane responses are calculated with sound input on the oval window membrane. In order to study the effects of helicotrema on basilar membrane response, three different helicotrema dimensions are set up in the FE model. A two-way fluid-structure interaction numerical method is used to compute the responses in the cochlea. The influence of the helicotrema is acquired and the frequency selectivity of the basilar membrane motion along the cochlear duct is predicted. These results agree with the experiments and indicate much better results are obtained with appropriate helicotrema size.


2013 ◽  
Vol 589-590 ◽  
pp. 157-162
Author(s):  
Ya Hui Hu ◽  
Qing Yun Zhang ◽  
Xiao Yu Yue

The changes of drilling forces during bone drilling provide a useful index for evaluating the risk of potential damage to the bone. The aim of the work is that an elastic-plastic dynamic finite element model is used to simulate the process of a drill bit drilling through the bone. The finite element model was set up in the Abaqus6.11; the prediction model of the drilling force was gotten by using the regression orthogonal experiment and data processing software Matlab7.0. Diverse values of drilling speed, feed rate and drill diameter are important factors which will lead to changes in the drilling forces. By controlling the drilling parameters can obtain the optimal drilling force. The results show that the diameter has the greatest influence on the drilling force, the drilling speed the second, the feed rate the last.


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