scholarly journals Statistical Estimation of Resistance to Cyclic Deformation of Structural Steels and Aluminum Alloy

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 47
Author(s):  
Žilvinas Bazaras ◽  
Vaidas Lukoševičius

Resistance to cyclic loading is a key property of the material that determines the operational reliability of the structures. When selecting a material for structures operating under low-cycle loading conditions, it is essential to know the cyclic deformation characteristics of the material. Low-cycle strain diagrams are very sensitive to variations in chemical composition, thermal processing technologies, surface hardening, loading conditions, and other factors of the material. The application of probability methods enables the increase in the life characteristics of the structures and the confirmation of the cycle load values at the design phase. Most research papers dealing with statistical descriptions of low-cycle strain properties do not look into the distribution of low-cycle diagram characteristics. The purpose of our paper is to provide a probability assessment of the low-cycle properties of materials extensively used in the automotive and aviation industries, taking into account the statistical assessment of the cyclic elastoplastic strain diagrams or of the parameters of the diagrams. Materials with contrasting cyclic properties were investigated in the paper. The findings of the research allow for a review of durability and life of the structural elements of service facilities subjected to elastoplastic loading by assessing the distribution of low-cycle strain parameters, as well as the allowed distribution limits.

Author(s):  
Alexander Zvorykin ◽  
Roman Popov ◽  
Mykola Bobyr ◽  
Igor Pioro

Analysis of engineering approach to the operational life forecasting for constructional elements with respect to the low-cycle fatigue is carried out. Applicability limits for a hypothesis on existence of generalized cyclic-deforming diagram in case of complex low-cycle loading (deforming) are shown. It is determined, that under condition of plane-stress state and piecewise-broken trajectories of cycle loading with stresses and deformation checking the cyclic deforming diagram is united in limits of deformations, which are not exceeded 10 values of deformation corresponding material yield point. Generalized kinematic equation of material damageability is described. The method of damageability parameter utilization for increasing of accuracy calculation of structural elements low-cycle fatigue by using the effective coefficients of stresses and deformations taking into account the damageability parameter is given.


2019 ◽  
Vol 8 (11) ◽  
pp. 509-517 ◽  
Author(s):  
Kyoung-Tak Kang ◽  
Yong-Gon Koh ◽  
Kyoung-Mi Park ◽  
Chong-Hyuck Choi ◽  
Min Jung ◽  
...  

Objectives The aim of this study was to investigate the biomechanical effect of the anterolateral ligament (ALL), anterior cruciate ligament (ACL), or both ALL and ACL on kinematics under dynamic loading conditions using dynamic simulation subject-specific knee models. Methods Five subject-specific musculoskeletal models were validated with computationally predicted muscle activation, electromyography data, and previous experimental data to analyze effects of the ALL and ACL on knee kinematics under gait and squat loading conditions. Results Anterior translation (AT) significantly increased with deficiency of the ACL, ALL, or both structures under gait cycle loading. Internal rotation (IR) significantly increased with deficiency of both the ACL and ALL under gait and squat loading conditions. However, the deficiency of ALL was not significant in the increase of AT, but it was significant in the increase of IR under the squat loading condition. Conclusion The results of this study confirm that the ALL is an important lateral knee structure for knee joint stability. The ALL is a secondary stabilizer relative to the ACL under simulated gait and squat loading conditions. Cite this article: Bone Joint Res 2019;8:509–517.


Author(s):  
Valeriy V. Kirilovskiy ◽  
Yuri V. Belousov

Bearing units of lifting machines, products of construction, road, aviation, space and other branches of technology are very important structural elements, since the failure of even one bearing can cause the failure of the entire product. The results of experimental verification of the theoretical model of bearing operation under combined loading conditions are presented. The behavior under load of bearing units in the most general case can be represented by a sequence of five design schemes, expressed in the form of five statically indeterminate beams. The purpose of the experiments was to test this model under real loading conditions. The experiments were based on the analysis of the geometric shape of the curved elastic line, which the shaft of the bearing assembly acquires under load. The experimental results confirmed the validity of the model and showed that the previously generally accepted model of a two-support beam is not implemented. The conclusion is confirmed that in responsible lifting machines, as well as in responsible products of construction, road, aviation, space and other branches of technology, it is impractical to calculate bearings according to the traditional method, since an erroneous value of bearing durability can be obtained, overestimated from 28.37 to 26.663.9 times.


2020 ◽  
Vol 10 (18) ◽  
pp. 6327
Author(s):  
Alberto Campagnolo

This Special Issue covers the broad topic of structural integrity of components subjected to either static or fatigue loading conditions, and it is concerned with the modelling, assessment and reliability of components of any scale. Dealing with fracture and fatigue assessments of structural elements, different approaches are available in the literature. They are usually divided into three subgroups: stress-based, strain-based and energy-based criteria. Typical applications include materials exhibiting either linear-elastic or elasto-plastic behaviours, and plain and notched or cracked components subjected to static or cyclic loading conditions. In particular, the articles contained in this issue concentrate on the mechanics of fracture and fatigue in relation to structural elements from nano- to full-scale and on the applications of advanced approaches for fracture and fatigue life predictions under complex geometries or loading conditions.


Author(s):  
А.А. Водяницкая

Постановка задачи. Работа посвящена изучению оценочных характеристик отзыва научного руководителя, функционирующего в рамках академического дискурса. Впервые выявляются оценочные стратегии и тактики научного руководителя, вербализованные в отзыве при характеризации научно-исследовательской работы магистранта и бакалавра. Результаты. Как показало исследование, посредством оценочных значений, которые выстраивают отзыв о работе выпускника над выпускной квалификационной работой, научные руководители положительно характеризуют исследовательские навыки студентов. Отрицательные оценочные значения не вербализуются, но имплицируются в рекомендациях уделять внимание в дальнейшей работе, например, более планомерной организации исследования. Наиболее универсальной и распространённой характеристикой работы студента является формулировка академический дискурс сформирован , которая включает в себя все положительные оценочные значения, релевантные для научно-исследовательской деятельности в рамках академического дискурса. Во всех структурных элементах отзыва научные руководители прибегают к использованию оценочных значений. В наименьшей степени оценочные значения представлены в разделе Умение работать с научной, методической, справочной литературой и электронными информационными ресурсами. Выводы. Отзыв научного руководителя как жанр академического дискурса представляет собой амальгаму оценочных средств, с помощью которых научный руководитель эксплицирует, а в некоторых случаях и имплицирует своё отношение к проделанной студентом работе. В качестве объекта оценки служат те аспекты научно-исследовательской деятельности, которые выделены как структурные элементы отзыва, а также дополнительные объекты, которые научный руководитель считает необходимым выделить. В ходе исследования были выделены оценочные стратегии импликации, интенсификации, рекомендации и констатации. Problem Statement. The paper focuses on evaluative characteristics of research advisors’ reviews functioning in the framework of academic discourse. Evaluative strategies and tactics have been revealed for the first time as a part of a research advisor’s review. Results. The research has shown that research advisors characterize positively various aspects of graduate students’ research papers and the way they organized their research work. Negative evaluations are not verbalized, but teachers implicitly mention that their students should organize their work more thoroughly in the future. The fact that academic discourse has been acquired by the student to the full extent serves as a positive characteristic of their work, and, therefore, includes all the evaluations relevant for doing a research and for research results. In all the structural elements of the reviews research advisors use a variety of evaluative means. The latter are represented to a lesser extent in the structural element concerning the Ability of a student to retrieve information and to use a variety of information resources. Conclusion. Research advisor’s review as a genre of academic discourse is an amalgam of evaluative means which enable the research advisor to explicitly verbalize his attitude towards a student research work. Evaluative means characterize those aspects of research work which are specified in the body of the review as structural elements. Moreover, teachers specifies work ethic, ethical behavior, personal characteristics that are crucial for the research work. The research has revealed evaluative strategies of intensification, recommendation, stating and implication.


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