Announcing a seminar on a new approach for inelastic analysis of structures

Zarka, J.; Frelat, J.; Navidi-Kasmai, P.

doi:10.1016/0749-6419(91)90024-s

Cited by 36 publications

(38 citation statements)

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“…A first line of research is concerned with extensions of the original theorem to various nonlinear behaviors, such as hardening plasticity (Pham, 2008;Nguyen, 2003), non standard plasticity (Corigliano et al, 1995;Bodovillé and De Saxcé, 2001), contact with friction (Ahn et al, 2008), phase-transformation (Peigney, 2010). A second (and complementing) line of research is concerned with the development of numerical methods for efficiently determining the shakedown domain in the space of load parameters (Zarka et al, 1988;Maitournam et al, 2002;Carvelli et al, 1999;Peigney andStolz, 2001, 2003;Simon and Weichert, 2012;Spiliopoulos and Panagiotou, 2012). We refer to Weichert and Ponter (2014) for more historical details on the development of shakedown theory.…”

Section: Introductionmentioning

confidence: 99%

Shakedown of elastic-perfectly plastic materials with temperature-dependent elastic moduli

Peigney

2014

Journal of the Mechanics and Physics of Solids

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For elastic-perfectly plastic materials with constant properties, the well-known Melan's theorem gives a sufficient condition for shakedown to occur, independently on the initial state. It has been conjectured that Melan's theorem could be extended to temperature-dependent (or time-dependent) elastic moduli, but no theoretical result is available. This paper aims at providing results in that direction, with a special emphasis on time-periodic variations. If Melan's condition is satisfied, we show that shakedown indeed occurs provided the time fluctuations of the elastic moduli satisfy a certain condition (which in particular is fulfilled if the time fluctuations are not too large). We provide a counterexample which shows that setting such a constraint on the elastic moduli is necessary to reach path-independent theorems as proposed. A simple mechanical system is studied as an illustrative example.

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Section: Introductionmentioning

confidence: 99%

Shakedown of elastic-perfectly plastic materials with temperature-dependent elastic moduli

Peigney

2014

Journal of the Mechanics and Physics of Solids

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“…The equivalent stress is shown in equation (5). Bolt tensioner has many advantages such as better accuracy and reliability of tightening load, high tightening load capacity, no torsion stress, no damage on bearing surfaces, easy simultaneous tightening.…”

Section: Tightening With Hydraulic Bolt Tensioner (Refs [1-3])mentioning

confidence: 99%

Optimal tightening process of bolted joints

Monville¹

2016

Int. J. Simul. Multisci. Des. Optim.

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-Threaded fasteners were developed long time (let's remember that Archimedes -287-212 BC -invented the water screw). Nowadays, bolted joints are used in almost all sectors of the industry. But in spite of having been an important machine part for centuries, problems may be encountered with them. They are so common that they are taken for granted and too often, not analyzed as deeply as it should be. The wrong tightening is one of the most frequent causes of ductile rupture and by far the most frequent cause of fatigue failure. The tightening operation is never easy. It is necessary to pay particular attention to the choice of the tightening tool, the process and the control method. The tightening operation may itself cause damage on parts. The tightening load must not be too low, or excessive or not equally distributed among the bolts. These three defects can even be made on the same bolted joint! This impacts badly the performance of the assembly and leads to a shorter lifespan. If insufficient precautions are taken, the real tightening preload on all the bolts will not fit well with the requirements and would be badly distributed. Consequently, the practical conditions are quite different from the hypothesizes which are taken for the initial calculations (analytics or FEM) at the design stage. Thus, the results of the calculations of bolted joints cannot be considered as accurate and reliable. Practically, there are several means to tighten a bolt. The two ways most frequently used are torque wrench and hydraulic bolt tensioner. Torque wrench involves exerting a torque to the bolt head or the nut. Hydraulic bolt tensioner applies a traction load directly on the bolt. It is well known that bolt tensioners give better accuracy and homogeneity in the final tightening load than the torque method, but the tension load applied with the tensioner must be higher than the final remaining tightening load. So, the paper focusses on the hydraulic tensioner to show how the tightening load can be obtained from the applied tension load and to propose a way to optimize and secure the tightening process. However, for the reasons above mentioned it appears necessary to first make a general description of technical aspects of bolted joints. What really happens when tightening with torque wrench or with bolt tensioner is explained.

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“…independent on any residual stress that may exist initially in the structure. The shakedown theory has been the object of numerous developments, regarding both extensions of the original theorem to various nonlinear behaviors [4,5,6,7,8,9] and numerical methods for assessing the shakedown limits in the case of parametrized loading histories [10,11,12,13,14,15,16].…”

Section: Introductionmentioning

confidence: 99%

On Shakedown of Elastic-Plastic Bodies With Temperature Dependent Properties

Peigney¹

2016

Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)

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Abstract. For elastic-perfectly plastic structures under prescribed loading histories, the wellknown Melan's theorem gives a sufficient condition for shakedown to occur, i.e. for the evolution to become elastic in the large-time limit. The original Melan's theorem rests on the assumption that the material properties remain constant in time, independently on the applied loading. This communication addresses the long standing issue of extending Melan's theorem to temperaturedependent (or time-dependent) elastic moduli. The main motivation is to extend the range of applications of Melan's theorem to thermomechanical loading histories with large temperature fluctuations: In such case, the variation of the elastic properties with the temperature cannot be neglected. Some recent results obtained in perfect plasticity and viscoplasticity are presented and discussed.

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Announcing a seminar on a new approach for inelastic analysis of structures

Cited by 36 publications

References 0 publications

Shakedown of elastic-perfectly plastic materials with temperature-dependent elastic moduli

Shakedown of elastic-perfectly plastic materials with temperature-dependent elastic moduli

Optimal tightening process of bolted joints

On Shakedown of Elastic-Plastic Bodies With Temperature Dependent Properties

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