scholarly journals Machining Distortion Minimization of Monolithic Aircraft Parts Based on the Energy Principle

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1586
Author(s):  
Longxin Fan ◽  
Hui Tian ◽  
Liang Li ◽  
Yinfei Yang ◽  
Nenggan Zhou ◽  
...  

Machining distortion is a recurring problem in the machining of monolithic aircraft parts. This paper aims to study the machining distortion minimization of monolithic aircraft parts. Firstly, the energy principle of machining distortion was analyzed. Then, a rapid prediction model of the final part distortion for beam parts was proposed based on the equivalent stress, and the initial bending strain energy contained in the final part was used to characterize the bending distortion risk of the final part. Numerical simulation and milling experiments verified the effectiveness of the proposed prediction model. The relative error between the experimental and calculated results does not exceed 26.5%. Finally, the influence of initial residual stress fluctuation, part geometry and the part location on part distortion was analyzed from the energy point of view. The obtained results indicated that the expected final part distortion can be minimized by adjusting these three factors.

JOGED ◽  
2020 ◽  
Vol 16 (2) ◽  
pp. 188-201
Author(s):  
Chorine Nur Shofa

Jepaplok merupakan judul dari sebuah karya tari kelompok yang di dalamnya melibatkan sembilan penari perempuan. Kata Jepaplok yaitu berasal dari Njeplak (Manggap) dan Nyaplok (mencaplok). Karya tari ini berawal dari pertunjukan Jaranan di Tulungagung Jawa Timur. Barongan atau biasa disebut Caplokan/Jepaplok adalah penggambaran hewan mitologi berupa ular naga sebagai penguasa hutan yang jahat. Sosok yang dilihat dari segi visualnya menyeramkan dan ganas, serta dari sudut geraknya yang sangat ekspresif. Gerak-gerak dasar yang digunakan antara lain seperti leang-leong, ngaplak, ngepruk, sondongan, pattetan, dan sundangan. Karya tari Jepaplok terdiri dari 4 bagian adegan. Pada bagian introduksi dipertunjukkan sosok Barongan dan Jaranan yang berbeda ruang dan kemudian saling menyerang. Bagian 1 berfokus pada gerak Barongan tanpa menggunakan properti topeng. Pada bagian 2 persiapan penyerangan terhadap penari Jaranan, sehingga dalam bagian ini sudah menggunakan properti topeng. Bagian 3 lebih kepada esensi penggunakan topeng dan diolah dengan permainan ritme dan menggunakan komposisi berpasangan. Bagian 4 yaitu akhir dari pertunjukan karya tari Jepaplok yaitu perangan Barongan dan Jaranan. Tetapi pada bagian akhir ini tidak semata-mata saling berhadapan satu dengan yang lain melainkan hanya sebatas permainan per kelompok. ABSTRACT Jepaplok is the title of a workgroup in which dance involving nine female dancers. The word Jepaplok is derived from Njeplak (Mangap) and Nyaplok (annexed). This dance originated in the works of interest in dance salon when watching a show used Jaranan (dance horse) in Tulungagung, East Java. The point of view of the Director of the dance stopped when one of the characters enter the staging area performance Barongan. Suspenseful atmosphere emerges when section toward the battle between used Horse and Barongan. Barongan or commonly called Caplokan/Jepaplok is the depiction of mythological animals in the form of a dragon serpent as ruler of the evil forest. The figure is seen in terms of the Visual sinister and vicious, as well as from the point of highly expressive movements that inspired the stylist for him to dance in a group dance with paper based on motion and feel the music used Jaranan Sentherewe Tulungagung, East Java. The focus of the implementation work of the dance called Jepaplok is more to perangan and Barongan figures. Basic motion-motion that is used among other things such as leang-leong, ngaplak, ngepruk, sondongan, pattetan, and sundangan. In the work of this Jepaplok dance doesn't bring up the story and consists of four parts of the scene. On the introduction of a dance figure demonstrating Barongan and different spaces used Horse and then each other. Part one is more focused on motion the Barongan poured into members of the body of a dancer without using the mask property. In part two, namely more to preparation which showed Barongan attacks against dancers used Horse, so in this section are already using property mask. Part three more to the essence of the use of mask and mingled with the game rhythm and composition using paired. Part four, namely the ending of the show dance work Jepaplok, as in general the final part of the art used Horse namely perangan and Barongan used Horse. But in the end, it does not solely face each other with one another but rather only as a game between groups.


2012 ◽  
Vol 504-506 ◽  
pp. 77-82 ◽  
Author(s):  
Liana Paraianu ◽  
Dan Sorin Comsa ◽  
Ioan Pavel Nicodim ◽  
Ioan Ciobanu ◽  
Dorel Banabic

The accuracy of the forming limit curves predicted by the Marciniak-Kuczynski model depends on the type and flexibility of the constitutive equations used to describe the mechanical response of the sheet metal. From this point of view, the yield criterion has the most significant influence. The paper presents a comparative analysis referring to the quality of the forming limit curves predicted by the Marciniak-Kuczynski model for the case when the plastic anisotropy of a DC04 sheet metal is described by the BBC2005 yield criterion. The coefficients included in the expression of the BBC2005 equivalent stress are evaluated using different identification strategies (with 4, 6, 7, and 8 mechanical parameters). The forming limit curves predicted by the Marciniak-Kuczynski model in each of the cases previously mentioned are compared with experimental data.


2021 ◽  
Vol 604 (9) ◽  
pp. 61-72
Author(s):  
Kinga Kuszak

Abstract The article tackles the issue of defining the concept of “adult-child communication” from the point of view of female students of pedagogy, future teachers and educators. The introduction explains the issue of symbolic representation of real and imagined objects, events, and situations by means of concepts and their definitions. The next part of the article describes the results of a study carried out in the group of 255 female students, who were asked to define the concept of “adult-child communication”. The study yielded a description of the concepts used to describe the defined concept and the signs of evaluation contained in the definitions. The final part of the article identifies and outlines four categories of the “adult-child communication” concept and discusses three types of definitions created by the respondents. The following types were distinguished: definitions similar to professional ones in terms of content and form, common definitions regarding the child-adult relationship with elements of professional vocabulary, common definitions and puerile definitions.


Author(s):  
Cijing Sun ◽  
Lisha Chen ◽  
Jinguo Liu ◽  
Jian S Dai ◽  
Rongjie Kang

Continuum robots have attracted increasing attention in recent years due to their intrinsic compliance and safety. Nevertheless, the use of structure compliance may lead to reduction of stiffness and positioning precision. This paper presents a novel design of a hybrid continuum robot whose actuators are composed of pneumatic muscles and embedded elastic rods. Such robot can switch drive modes between large-scale movement and fine adjustment of position by employing a locking mechanism to change its stiffness. A three-dimensional static model of the robot is presented using an improved Kirchhoff rod theory, where elastic deformation of the robot is accounted for from an optimal control point of view via minimal total potential energy principle. Experiments were carried out to validate the static model and to test the stiffness and precision of the robot. This work provides a possible way to strengthen the control precision of a continuum robot with compliant structure.


2013 ◽  
Vol 4 (4) ◽  
pp. 50-58 ◽  
Author(s):  
Janusz Pobożniak

Abstract The paper focuses on the algorithm for the recognition of manufacturing features defined in ISO 14649 (STEP-NC). First, the features defined in STEP-NC standard are discussed and then commonly used feature recognition methods are presented. Then the developed algorithm for recognition is presented in details starting with the discussion of STEP-NC features from the point of view of their recognition. The steps of the algorithm responsible for the recognition of profile based, transition and group features are presented. The software developed to verify the algorithm is also described. The final part includes the directions for the future research works. This paper adds to the works aimed to strengthen the position and use the full benefits of this new ISO 14649 standard.


2017 ◽  
Vol 1 (2) ◽  
pp. 74-83
Author(s):  
Lívia Trellová

This paper deals with conceptual and functional diversity of the Ombudsman Institution in Asia from comparative constitutional point of view. The author analyses ombudsman institution in Asia. Characteristics and definiton of Ombudsman made by European legal doctrine and also by the International Bar Association resolution was used as an starting point to set certain criteria upon which Asian ombudsman institutions are subject to comparative anaysis. Final part throws light on the prospects and problems of models, establishment and functioning of ombudsman institutions in Asia.


LingVaria ◽  
2019 ◽  
Vol 14 (28) ◽  
Author(s):  
Katarzyna Sicińska

The Honorificative Formula in 18th c. Polish Letters The paper discusses, from the formal, semantic, pragma- and sociolinguistic point of view, the honorificative formula that constituted one of the components of the final part of an epistolary Polish text of the 18th century. Most commonly, it took the shape of a conventionalized phrase which consisted of the preposition z (‘with’), an adjective, and a noun; e.g. z prawdziwym szacunkiem ‘with true respect’. The formula was syntactically dependent, as it was part of a larger whole – nearly always the subscription, i.e. the broadly understood signature of the author of the letter. The lexical composition of the formula showed considerable diversity. The nouns that constituted it include estymacja ‘esteem’, poważenie ‘reverence’, szacunek ‘respect’, weneracja ‘veneration’, and others. The attributes that described the main stem of the formula were also characterized by notable semantic diversity. Moreover, the honorificative formula could also appear in the form of a Latin quotation, e.g. profundo cultu. The usage of the formula depended on social and situational factors, namely it was used in letters to people of equal or higher social status (e.g. to members of princely families), as well as in highly official situations.


2020 ◽  
Author(s):  
Gianfranco Cianchini ◽  

<p>Earthquakes, the most energetic phenomena in the lithosphere, often cause danger and casualties: thus, their study and comprehension are greatly worth doing because of the obvious importance for society. Geosystemics intends to offer a way to study the Earth system by viewing it as a whole, looking at the possible couplings among the different geo-layers, i.e., from the earth’s interior up to the ionosphere through the atmosphere. It uses specific universal tools to integrate different methods that can be applied to multi-parameter data, often taken on different platforms (e.g., ground, marine or satellite observations). Its main aim is to understand the particular phenomenon of interest from a holistic point of view. Central is the use of entropy, together with other physical quantities that are introduced case by case. In this paper, we will deal with earthquakes, as final part of a long-term chain of processes involving, not only the interaction between different components of the Earth’s interior but also the coupling of the solid earth with the above neutral or ionized atmosphere, and finally culminating with the main rupture along the fault of concern. Particular emphasis will be given to some Italian seismic sequences.</p>


2021 ◽  
Vol 18 (3) ◽  
pp. 293-307
Author(s):  
Claudio Paolucci

Abstract In this paper I will try to outline the reasons why, in order to understand the life and the nature of meaning, the semiotic tradition has always thought that it was better not to separate semantics and pragmatics. I will first reconstruct the history of this idea, grounded in Pragmatism and in Structural Linguistics. Later, I will deal with its first formulation in A Theory of Semiotics by Umberto Eco. In the second part of the paper, I will work on the idea by Ferdinand de Saussure that meanings are values, that is, indeterminate entities whose identity is determined only through reciprocal determination. I will claim that this idea is the importation in linguistics of Leibniz’s principles of the differential calculus. In the final part of the paper, I will apply this idea to the distinction between semantics and pragmatics, claiming that meanings are better understood through a theory of modes of existence. If we understand the differential nature of meaning, we can see that meanings live only through the using of the expressions and these variations contribute to offer stability within the transformations, without creating a stable object defined by its properties and endowed with an independent existence split from the relationships that define it.


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