Tolerance analysis — Form defects modeling and simulation by modal decomposition and optimization

Tolerance analysis aims on checking whether specified tolerances enable functional and assembly requirements. The tolerance analysis approaches discussed in literature are generally assumed without the consideration of parts’ form defects. This paper presents a new model to consider the form defects in an assembly simulation. A Metric Modal Decomposition (MMD) method is henceforth, developed to model the form defects of various parts in a mechanism. The assemblies including form defects are further assessed using mathematical optimization. The optimization involves two models of surfaces: real model and difference surface-base method, and introduces the concept of signed distance. The optimization algorithms are then compared in terms of time consumption and accuracy. To illustrate the methods and their respective applications, a simplified over-constrained industrial mechanism in three dimensions is also used as a case study

Probabilistic-based approach using Kernel Density Estimation for gap modeling in a statistical tolerance analysis

The statistical tolerance analysis has become a key element used in the design stage to reduce the manufacturing cost, the rejection rate and to have high quality products. One of the frequently used methods is the Monte Carlo simulation, employed to compute the non-conformity rate due to its efficiency in handling the tolerance analysis of over-constrained mechanical systems. However, this simulation technique requires excessive numerical efforts. The goal of this paper is to improve this method by proposing a probabilistic model of gaps in fixed and sliding contacts and involved in the tolerance analysis of an assembly. The probabilistic model is carried out on the clearance components of the sliding and fixed contacts for their assembly feasibility considering all the imperfections on the surfaces. The kernel density estimation method is used to deal with the probabilistic model. The proposed method is applied to an over-constrained mechanical system and compared to the classical method regarding their computation time

Высокие технологии в современной науке и технике (ВТСНТ-2017): сборник научных трудов VI Международной научно-технической конференции молодых ученых, аспирантов и студентов, г. Томск, 27–29 ноября 2017 г.

В сборнике представлены материалы по следующим направлениям исследований: технологии материалов новых поколений и наноматериалов; оптические технологии; органическая химия и биотехнологии; рациональное использование минеральных и водных ресурсов; проблемы надежности машиностроения и машиностроительные технологии; моделирование физико-химических процессов в современных технологиях. Целью конференции ВТСНТ-2017 является развитие кооперации российских и зарубежных молодых ученых и студентов в проведении научных исследований в области современных высоких технологий. Сборник представляет интерес для молодых ученых - физиков и химиков, интересующихся проблемами материаловедения, новых материалов и рационального использования природного сырья