Local strength properties of steel bars as random functions

In subproject B1, local physical and geometrical effects which have only been observed so far as side effects in the laser joining process, are to be used purposefully, in order to achieve graded strength properties and to improve the component rigidity significantly. One aim of the work in the first requested period is the investigation of effects of laser-based joining connections on the structure rigidity for simplified sample geometries. A defined local strength increase will first be done on blind seams and later on seams with suitable seam geometries. In the context of SFB 675, laser joining processes are to be developed further so that the final assembly can take place with and other methods to increase strength for semi-finished products without considerably changing the local material characteristics. Beyond that, general rigidity effects of the connections are to be used purposefully for rigidity improvement.

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Analysis of the joint application results of a borehole jack and thermal drilling in ice research

Arctic and Antarctic Research ◽

10.30758/0555-2648-2018-64-2-157-169 ◽

2018 ◽

Vol 64 (2) ◽

pp. 157-169

Author(s):

V. V. Kharitonov ◽

A. I. Shushlebin

Keyword(s):

Penetration Rate ◽

Ice Cover ◽

Strength Properties ◽

Drilling Equipment ◽

Joint Application ◽

Local Strength ◽

Rate Versus ◽

Thermal Drilling ◽

Ice Strength ◽

Comparison Of The Results

In last two decade, studies of ice ridge morphometry and strength properties have been actively carried out. Thermal drilling of ice and experiments to determine the local strength of ice using a borehole jack are performed. The paper discusses the issues of joint use of thermal drilling equipment and borehole jack for the ice cover research. Two approaches to the comparison of the results obtained by these two methods are considered. Average penetration rate versus local ice strength dependences are presented. With increasing ice strength and decreasing penetration rate the interval of changes in the ice strength increases and correspondence of the strength to the penetration rate decreases. Based on the results of ice ridges research, depth-wise distributions of local strength and thermal drill penetration rate are compared. Difference between the average thicknesses of the consolidated layer obtained from these distributions was 5 %.

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Effect of technological modes of stampings on strength properties of rocket and space equipment parts

Blanking productions in mechanical engineering (press forging, foundry and other productions) ◽

10.36652/1684-1107-2021-19-6-281-287 ◽

2021 ◽

pp. 281-287

Author(s):

V.S. Muratov ◽

M.S. Kazakov

Keyword(s):

Heat Treatment ◽

Tensile Tests ◽

Strength Properties ◽

Space Technology ◽

Deformation Processing ◽

Premature Failure ◽

Locking Mechanism ◽

Steel Bars ◽

Processing Modes ◽

Highly Loaded

The reasons for premature failure during vibratory tests and tensile tests of highly loaded parts of the locking mechanism made by stamping from AISI 5140 steel bars and used in rocket and space technology are studied. It is determined that destruction is caused by the microlaminations in metal formed during heat treatment. Recommendations for adjusting of the deformation processing modes of forgings, ensuring the exclusion of premature destruction cases, are developed.

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Fatigue Life Calculation Concepts for Structures with Inhomogenous Strength Properties

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.22.91 ◽

2007 ◽

Vol 22 ◽

pp. 91-99 ◽

Cited By ~ 1

Author(s):

Alfons Esderts ◽

Rainer Masendorf ◽

Tim Medhurst

Keyword(s):

Fatigue Life ◽

Collaborative Research ◽

High Strength ◽

Fatigue Behaviour ◽

Strength Properties ◽

Research Project ◽

Cold Forming ◽

Metal Structures ◽

Local Strength ◽

Actual Design

A fast transfer of new manufacturing- and material technologies to actual design use is only to be expected if calculation concepts exist, which allow an easy estimation of the parts’ strength properties. This Collaborative Research Project (CRP) will develop new manufacturing and joining techniques to create high strength structures by adjusting the local strength properties of parts. These types of structures are usually loaded dynamically. To specifically optimise the fatigue behaviour, stiffness and weight of a structure, the influences of locally strengthening manufacturing processes must be considered in the fatigue life calculation concept. It is the goal of this project to include a simulation of the fatigue behaviour in the process simulation of manufacturing. Recently research on the influence of local strengthening by cold forming on fatigue life was undertaken in cooperation within another research project. The fatigue life calculation of sheet metal structures can be based on a calculation concept developed in CRP 362, subproject C5, which takes into account the influence of forming, [1,2,3,4]. This concept shall be extended to incorporate the effects of local martensite forming in the cold formed areas.

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Effect of standing waves on the local strength of modeled ice field

Доклады Академии наук ◽

10.31857/s0869-56524896564-569 ◽

2019 ◽

Vol 489 (6) ◽

pp. 564-569

Author(s):

V. P. Epifanov ◽

K. E Sazonov

Keyword(s):

Wave Process ◽

Periodic Structures ◽

Standing Waves ◽

Ice Cover ◽

Strength Properties ◽

Strength Characteristics ◽

Local Strength ◽

Ice Field

Two scenarios of the influence of standing waves on the strength properties of ice lying on the surface of the liquid are considered: in the process of freezing the ice field and as a result of instability, which is caused by compression on the pool walls due to the expansion of water during freezing. The obtained experimental hardness profiles of the ice field indicate the formation of periodic structures characteristic of the wave process. It is shown that in both cases the standing waves arising in the basin change the strength characteristics of the ice cover.

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Lightweight and reliable metal–composite joints based on harmonization of strength properties of joined parts

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410018778797 ◽

2018 ◽

Vol 232 (14) ◽

pp. 2663-2672 ◽

Cited By ~ 1

Author(s):

Andrey Chernov ◽

Danil Fomin ◽

Ivan Kondakov ◽

Ivan Mareskin ◽

Alexander Shanygin

Keyword(s):

Laminated Composite ◽

Strength Properties ◽

Experimental Investigations ◽

Composite Joints ◽

Metal Composite ◽

Metallic Part ◽

Maximal Load ◽

Local Strength ◽

Metallic Parts ◽

Local Stiffness

One of the key problems of designing composite primary aircraft structures is the problem of development of lightweight and reliable joints for such structures. For conventional bolted joints used for connection of laminated composite primary structure elements, the loads are transferred via the contact of metallic and composite parts having considerably different strength and stiffness parameters. As the local strength properties of composites are defined by polymer resins, having several times less strength as compared to the metallic alloys, the maximal load that can be transferred via the joint is limited by the properties of resins. As a consequence, the metallic parts of such joints are loaded to a very low extent, that causes low weight efficiency. In the presented paper, the approach to development of metal–composite joints based on the principle of harmonization is proposed. The harmonization principle is to minimize the disbalance of strength properties of metallic and composite parts in the local zones of contact. This principle can be realized by two ways: either by removing the resin from the zone of contact to increase local stiffness of composite part (“stiff” joint concept) or by creation of metallic part with porous structure to decrease local stiffness of the metallic part (“soft” joint concept). In this paper, the evaluation of both concepts is given, based on numerical and experimental investigations carried out in this work.

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SEM Study of Tension Wood Fiber Morphology and its Effect on Paper Properties

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100079061 ◽

1977 ◽

Vol 35 ◽

pp. 308-309

Author(s):

K. W. Robinson

Keyword(s):

Tension Wood ◽

Wood Fiber ◽

Strength Properties ◽

Fiber Morphology ◽

Paper Properties ◽

Pure Cellulose ◽

Short Rotation ◽

Hardwood Trees ◽

Sem Study

Tension wood (TW) is an abnormal tissue of hardwood trees; although it has been isolated from most parts of the tree, it is frequently found on the upper side of branches and leaning stems. TW has been classically associated with geotropic alignment, but more recently it has been associated with fast growth. Paper made from TW is generally lower in strength properties. Consequently, the paper industries' growing dependence on fast growing, short- rotation trees will result in higher amounts of TW in the final product and a corresponding reduction in strength.Relatively few studies have dealt with the role of TW in the structure of paper. It was suggested that the lower strength properties of TW were due to a combination of factors, namely, its unique morphology, compression failures in the cell wall, and lower hemicellulose content. Central to the unique morphology of the TW fiber is the thick gelatinous layer (G-layer) composed almost entirely of pure cellulose.

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