Analysis of Residual Stresses in a Polymer Cylinder when it is Stopped and then Cooled in a Nonlinear and Linearized Problem Settings

2021 ◽  
Vol 899 ◽  
pp. 486-492
Author(s):  
Liubov I. Lesnyak ◽  
Vladimir I. Andreev ◽  
Serdar B. Yazyev ◽  
Arthur A. Avakov ◽  
Irina G. Doronkina
Keyword(s):  
Stress State ◽  
Residual Stresses ◽  
The Body ◽  
Linearized Problem ◽  
Deformed State ◽  
Problem Setting

In conclusion, one should say that, to determine the approximate stress state in the body, it is quite enough to consider the problem in a linearized problem setting. When determining the deformed state, it is necessary to consider the problem exclusively in a nonlinear setting.

About Residual Stress State of Castings: The Case of HPDC Parts and Possible Advantages through Semi-Solid Processes

2022 ◽  
Vol 327 ◽  
pp. 272-278
Author(s):  
Elisa Fracchia ◽  
Federico Simone Gobber ◽  
Claudio Mus ◽  
Yuji Kobayashi ◽  
Mario Rosso
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Residual Stresses ◽  
Casting Process ◽  
Ray Method ◽  
Premature Failure ◽  
Thin Walls ◽  
Residual Stress State ◽  
Semi Solid ◽  
Pressure Die Casting

Nowadays, one of the most crucial focus in the aluminium-foundry sector is the production of high-quality castings. Mainly, High-Pressure Die Casting (HPDC) is broadly adopted, since by this process is possible to realize aluminium castings with thin walls and high specific mechanical properties. On the other hand, this casting process may cause tensile states into the castings, namely residual stresses. Residual stresses may strongly affect the life of the product causing premature failure of the casting. Various methods can assess these tensile states, but the non-destructive X-Ray method is the most commonly adopted. Namely, in this work, the residual stress analysis has been performed through Sinto-Pulstec μ-X360s. Detailed measurements have been done on powertrain components realized in aluminium alloy EN AC 46000 through HPDC processes to understand and prevent dangerous residual stress state into the aluminium castings. Furthermore, a comparison with stresses induced by Rheocasting processes is underway. In fact, it is well known that Semi-Solid metal forming combines the advantages of casting and forging, solving safety and environmental problems and possibly even the residual stress state can be positively affected.

Residual Stress Formation at Arbitrary Types of Rollers during the Running in Process

2012 ◽  
Vol 548 ◽  
pp. 372-376
Author(s):  
O.P. Muraviev ◽  
M.R. Sikhimbayev ◽  
B.N. Absadykov ◽  
B.S. Arymbekov ◽  
Y.O. Tkacheva
Keyword(s):  
Residual Stresses ◽  
Surface Deformation ◽  
Calculated Data ◽  
Sharp Decrease ◽  
The Body ◽  
Experimental Investigations ◽  
Body Parts ◽  
Adequate Treatment ◽  
Significance Level ◽  
Plastic Surface

In the article the results of the design and analysis of mathematical model for determining residual stresses in the surface of layer at parts processed by plastic surface deformation (PSD) in which the rollers having an arbitrary shape and size. It is shown that for the calculation of stresses in the surface of layer it should not be defined by them at a forcing point but by a function of contact stresses. Integral equations are obtained for calculating the stresses in the body parts at the processing of PSD rolls of arbitrary size and shape of the stress distribution over the contact area. We found that the tangential and radial residual stresses depend on the magnitude of the force F and its distance from the point at which the voltage is considered in detail. There is a sharp decrease in the influence of forces on the stress in the surface of the part of the distance to the point in question.The calculated data generated by the proposed method are highly matches with data during the experimental investigations. Maximum deviations of the calculated values do not exceed the errors of the experiments and adequate treatment of each other at a significance level of 0.05.

scholarly journals A damage initiation criterion for a class of viscoelastic solids

2018 ◽  
Vol 474 (2214) ◽  
pp. 20180064
Author(s):  
P. Alagappan ◽  
K. R. Rajagopal ◽  
K. Kannan
Keyword(s):  
Ad Hoc ◽  
The Body ◽  
Relevant Parameter ◽  
Elastic Solids ◽  
Viscoelastic Solids ◽  
Damage Initiation ◽  
Link Type ◽  
Deformed State ◽  
Voigt Model ◽  
Math Phys

We extend the methodology introduced for the initiation of damage within the context of a class of elastic solids to a class of viscoelastic solids (Alagappan et al. 2016 Proc. R. Soc. Lond. A: Math. Phys. Eng. Sci. 472 , 20160231. ( doi:10.1098/rspa.2016.0231 )). In a departure from studies on damage that consider the body to be homogeneous, with initiation of damage being decided by parameters that are based on a quantity such as the strain, that requires information concerning a special reference configuration, or the use of ad hoc parameters that have no physically meaningful origins, in this study we use a physically relevant parameter that is completely determined in the current deformed state of the body to predict the initiation of damage. Damage is initiated due to the inhomogeneity of the body wherein certain regions in the body are unable to withstand the stresses, strains, etc. The specific inhomogeneity that is considered is the variation of the density in the body. We consider damage within the context of the deformation of two representative viscoelastic solids, a generalization of a model proposed by Gent (1996 Rubber Chemistry and Technology 69 , 59–61. ( doi:10.5254/1.3538357 )) for polymeric solids and a generalization of the Kelvin–Voigt model. We find that the criterion leads to results that are in keeping with the experiments of Gent & Lindley (1959 Proc. R. Soc. Lond. A: Math. Phys. Eng. Sci. 249 , 195–205. ( doi:10.1098/rspa.1959.0016 )).

Investigation of Welded Joints Made of Construction Steel by the Barkhausen Noise Method

2020 ◽  
Vol 992 ◽  
pp. 957-963
Author(s):  
E. Nikolaeva ◽  
A. Nikolaev
Keyword(s):  
Stress State ◽  
Residual Stresses ◽  
Welded Joints ◽  
Arc Welding ◽  
Barkhausen Noise ◽  
Low Carbon ◽  
Butt Weld ◽  
Welded Structures ◽  
The Relationship ◽  
Weld Seams

Steel weld seams are characterized by heterogeneity of their microstructure. Microstructure affects the nature of the distribution, sign and magnitude of residual stresses. In combination with unfavorable factors (low temperature, metal hypoductility and an unsuccessful joint form) residual stresses lead to a decrease of load carrying capacity of a whole structure. In a weld seam residual stresses are distributed in a complex way and can affect the build quality of heavy section welded structures. Monitoring of residual stresses remains a big problem. Residual stresses in welds are often evaluated only by modeling. Unfortunately, all mathematical models describe the stress state of the welded material with low accuracy. Simple quality control, the results of which can be easy interpreted, is necessary. Welded joints made by manual arc welding and by automatic submerged arc welding were investigated. Butt seams of steel sheets of different thickness have been welded. Steel was low-carbon and low-alloyed. It is often used in welded structures for various purposes, including construction, and for pipelines manufacture. The temperature range of welded structures operation is very large – from-70 to 450С. The authors studied the structure of butt weld seams by the Barkhausen noise method, which is interesting as it represents an alternative to the known methods, which characterizes the structure and stress state of material. The relationship between the weld microstructure and magnetic noise is shown. Studies have allowed us to establish the relationship between the structure and magnetic properties and to evaluate the feasibility of applying the Barkhausen noise method to welded structures.

Surface Integrity of Biodegradable Magnesium-Calcium (Mg-Ca) Alloy by Low Plasticity Burnishing

2010 ◽  
Author(s):  
M. Salahshoor ◽  
Y. B. Guo
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Surface Integrity ◽  
Bulk Material ◽  
Large Diameter ◽  
Biological Response ◽  
The Body ◽  
Low Plasticity Burnishing ◽  
Sever Plastic Deformation ◽  
Biodegradable Magnesium

When a device is implanted into the body, into either hard or soft tissue, the body will respond. While the bulk material of the device is often important for integrity and mechanical success, the device surface is at the interface with biology. Major effort has been spent modifying a biomaterial surface in order to elicit or inhibit a biological response. Metallic biodegradable Magnesium-Calcium (Mg-Ca) alloys have attracted an increased attention for orthopedic fixation applications. This research focuses on low plasticity burnishing (LPB) as a novel surface modification technique that is added to the surface to control biodegradation as a biological response. The effects of burnishing pressure as an important process parameter on surface integrity characteristics such as surface roughness, surface topography, and residual stresses are investigated. Burnished surface roughness is smaller than the machined ones. However, some amount of waviness is observed which might be due to large diameter of the burnishing ball and sever plastic deformation. High compressive residual stresses are measured on the burnished surface.

CALCULATIONS OF STRESS-DEFORMED STATE OF LOW-DENSITY MATERIALS AND ITS APPLICATIONS TO BORON CARBIDE DURING EXPLOSIVE LOADING

2004 ◽  
Vol 18 (08) ◽  
pp. 1203-1215
Author(s):  
A. PEIKRISHVILI ◽  
P. LEMIS-PETROPOULOS ◽  
V. KAPAKLIS ◽  
C. POLITIS
Keyword(s):  
Stress State ◽  
Boron Carbide ◽  
High Temperatures ◽  
Shock Loading ◽  
Explosive Loading ◽  
Theoretical Density ◽  
Low Density ◽  
Two Stage ◽  
Constant Rate ◽  
Deformed State

Using hot explosive compacting technology and consolidating B 4 C powders in two stage at high temperatures enabled us to obtain compacts with high value of hardness and near theoretical density. This work contains results of calculations of B 4 C stress state under the shock loading that is being distributed evenly at a constant rate through the boundary retaining samples.

A Simple Estimating Method for Reduction of Welding Residual Stresses in Thick Welded Joint From Stress-Relief Annealing—Part IV: Applicability of the Simple Estimating Method for Stress-Relief Annealing of Thick Welded Joint

2002 ◽  
Vol 124 (2) ◽  
pp. 207-214 ◽  
Author(s):  
Keiji Nakacho
Keyword(s):  
Stress State ◽  
Stress Relaxation ◽  
Residual Stresses ◽  
Welded Joint ◽  
Uniaxial Stress ◽  
Stress Relief ◽  
Pressure Vessels ◽  
Relaxation Phenomenon ◽  
Multiaxial Stress ◽  
Creep Theory

Stress-relief annealing (SR treatment) is often applied to relieve welding residual stresses in the fabrication process of pressure vessels, etc. This study aims at development of an efficient method as simple as hand calculation to estimate reduction of residual stresses of a very thick welded joint by SR treatment. In the first report, an estimating method was developed for relaxation tests, in uniaxial stress state, at changing and constant temperatures because the stress relaxation phenomenon may be considerably similar to that observed in the SR treatment of a joint. In the second report, the stresses relaxed by SR treatment in a very thick welded joint were analyzed accurately by the finite element method based on thermal elastic-plastic creep theory. The characteristics of the changes of the welding residual stresses in multiaxial stress state were studied in detail for further development of the estimating method to SR treatment of a very thick welded joint, of which the stress state and boundary condition are very complex. In the third report, the estimating equations in multiaxial stress states were developed for the stress relaxation phenomenon in the thick welded joints, based on the foregoing characteristics. In this report, the applicability of the simple estimating method is investigated for SR treatment of the thick welded joint, by comparing the estimated results with the accurate ones obtained by FEM.

Modelling shattered rim cracking in railroad wheels

2011 ◽  
Vol 225 (6) ◽  
pp. 593-604
Author(s):  
V Sura ◽  
S Mahadevan
Keyword(s):  
Residual Stress ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Stress State ◽  
Intensity Factor ◽  
Residual Stresses ◽  
Equivalent Stress ◽  
Crack Tip ◽  
Residual Stress State

Shattered rim cracking, propagation of a subsurface crack parallel to the tread surface, is one of the dominant railroad wheel failure types observed in North America. This crack initiation and propagation life depends on several factors, such as wheel rim thickness, wheel load, residual stresses in the rim, and the size and location of material defects in the rim. This article investigates the effect of the above-mentioned parameters on shattered rim cracking, using finite element analysis and fracture mechanics. This cracking is modelled using a three-dimensional, multiresolution, elastic–plastic finite element model of a railroad wheel. Material defects are modelled as mathematically sharp cracks. Rolling contact loading is simulated by applying the wheel load on the tread surface over a Hertzian contact area. The equivalent stress intensity factor ranges at the subsurface crack tips are estimated using uni-modal stress intensity factors obtained from the finite element analysis and a mixed-mode crack growth model. The residual stress and wheel wear effects are also included in modelling shattered rim cracking. The analysis results show that the sensitive depth below the tread surface for shattered rim cracking ranges from 19.05 to 22.23 mm, which is in good agreement with field observations. The relationship of the equivalent stress intensity factor (Δ K eq) at the crack tip to the load magnitude is observed to be approximately linear. The analysis results show that the equivalent stress intensity factor (Δ K eq) at the crack tip depends significantly on the residual stress state in the wheel. Consideration of as-manufactured residual stresses decreases the Δ K eq at the crack tip by about 40 per cent compared to that of no residual stress state, whereas consideration of service-induced residual stresses increases the Δ K eq at the crack tip by about 50 per cent compared to that of as-manufactured residual stress state. In summary, the methodology developed in this article can help to predict whether a shattered rim crack will propagate for a given set of parameters, such as load magnitude, rim thickness, crack size, crack location, and residual stress state.

Study of the Residual Stresses Variation into the Sandwich Structure Subjected to Thermomechanical Loading

2018 ◽  
Vol 279 ◽  
pp. 113-118
Author(s):  
Khalid Messaoudi ◽  
Farida Bouafia ◽  
Fethi Benkhenafou ◽  
Lyes Douadji ◽  
Wei Wei Du
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress State ◽  
Residual Stresses ◽  
Mechanical Loading ◽  
Sandwich Structure ◽  
Thermomechanical Loading ◽  
Metal Interface ◽  
Risk Of Rupture ◽  
Different Types

The assembly of different types of materials like metals and ceramics forms a structure called sandwich structure, which need advanced techniques to joint it together like the thermo compression. However, the rise of residual stress caused by the discontinuity of nature of this type of sandwich material, like incompatibility of the characteristics, which creates a risk of rupture of the structure and limited the using range of these types of materials. In this paper, we study the bonding of ceramic and metal and we will focus on the role played by the ceramic element in the stress state of ceramic/ metal interface and the stresses evaluation by Finite Element when the structure is subjected to thermo-Mechanical loading.

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