Fatigue strength of tubular structural elements under bending oscillations. Report 2. Fatigue strength of tubular structural members under programmed loading

1994 ◽  
Vol 26 (4) ◽  
pp. 315-319
Author(s):  
O. N. Gerasimchuk ◽  
S. S. Gorodetskii ◽  
B. A. Gryaznov ◽  
Yu. S. Nalimov
Keyword(s):  
Fatigue Strength ◽  
Structural Elements ◽  
Structural Members

Stress Distribution in Joints in Panel Structures

2015 ◽  
Vol 1124 ◽  
pp. 209-218
Author(s):  
Pavel Svoboda ◽  
Karl Heinz Winter
Keyword(s):  
Practical Experience ◽  
Elastic Behavior ◽  
Complex Structures ◽  
Structural Elements ◽  
Structural Members ◽  
Long Term Effects ◽  
Linear Elastic ◽  
The Past ◽  
Current Design

Reinforced and pre-stressed concrete have been used increasingly for various kinds of complex structures in the past decades. The structures assembled from panels belong into this group. The current design methods rely on linear elastic analyses based on empirically derived material laws assuming homogeneous and isotropic material. Practical experience and various investigations however have indicated that majority of structures and structural elements are in fact stressed beyond the range of linear elastic behavior. In addition, long term effects may have a significant influence on the structural behavior of this category of structures and structural members.

scholarly journals Effect of Stress Ratio and Notch on Fatigue Strength of Commercial Pure Titanium

2020 ◽  
Vol 321 ◽  
pp. 11012
Author(s):  
IWATA Toshiaki
Keyword(s):  
Fatigue Strength ◽  
Fatigue Limit ◽  
Pure Titanium ◽  
Longitudinal Direction ◽  
Structural Members ◽  
Application Range ◽  
Seawater Corrosion ◽  
Significant Difference ◽  
Safe Side ◽  
Cp Ti

Titanium alloys such as Ti-6Al-4V are widely used in the aerospace domain worldwide; consequently, they have been extensively investigated, and the accumulated data has facilitated their use in the construction of structural members. In contrast, commercial pure (CP) Ti, which is cheaper than Ti alloys is widely used in the general industry, especially in the marine domain in Japan because it exhibits superior seawater corrosion resistance and biocompatibility. However, CP titanium has a strong anisotropy and consists of an hcp crystal structure; therefore, the strength data are insufficient owing to its short use history as a structural material, and some of its mechanical material properties remain unclear. Herein, the effect of mean stress and stress concentration on the fatigue strength of CP Grade 2 titanium was evaluated for the application range expansion of CP titanium. The results indicated that the fatigue limit in the longitudinal direction was 80–84% that in the transverse direction for smooth specimens. However, no significant difference was noted in the fatigue limit in both the directions for notched specimens. Furthermore, it was noted that it is necessary to apply at least Sa-0.5Su line to design the safe side in CP Grade 2 titanium.

scholarly journals The Possibilities of Improving the Fatigue Durability of the Ship Propeller Shaft by Burnishing Process

Machines ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 63
Author(s):  
Stefan Dzionk ◽  
Włodzimierz Przybylski ◽  
Bogdan Ścibiorski
Keyword(s):  
Fatigue Strength ◽  
Cold Rolling ◽  
Processing Parameters ◽  
Numerical Control ◽  
Automatic Process ◽  
Structural Elements ◽  
Fatigue Durability ◽  
Burnishing Process ◽  
Seawater Environment ◽  
Ship Propeller

Heavily loaded structural elements operating in a corrosive environment are usually quickly destroyed. An example of such an element is a ship propeller operating in a seawater environment. This research presents a fatigue resistance test performed on elements operating in seawater. Different processing parameters applied on the samples in particular were compared with the specimens whose surface had been burnished differently and they were compared to specimens with a grinded surface. The research shows that the structural elements whose surface has been burnished can have up to 30% higher fatigue strength in a seawater environment than the elements whose surface has been grinded. During burnishing, an important feature of the process is the degree of cold rolling of the material. The resistance of the component to fatigue loads increases only to a certain level with increasing the degree of the cold rolling. Further increasing the degree of cold rolling reduces the fatigue strength. Introducing additional stresses in the components (e.g., assembly stresses) reduces the fatigue strength of this component in operation and these additional stresses should be accounted for while planning the degree of the cold rolling value. A device that allows for simultaneous turning and shaft burnishing with high slenderness is presented in the appendix of this article. This device can be connected to the computerized numerical control system and executed automatic process according to the machining program; this solution reduces the number of operations and cost in the process.

Experimental Study on the Fire Resistance of Rectangular Hollow Sections Steel Columns

2012 ◽  
Vol 557-559 ◽  
pp. 112-115
Author(s):  
In Kyu Kwon ◽  
Heung Youl Kim ◽  
Hyung Jun Kim
Keyword(s):  
Engineering Design ◽  
Fire Resistance ◽  
Scientific Method ◽  
Maximum Temperature ◽  
Structural Elements ◽  
Structural Members ◽  
Building Collapse ◽  
Steel Columns ◽  
Fire Engineering ◽  
Limiting Temperatures

A fire occurring at a building causes severe damages to its structural members and brings unexpected collapse. Therefore, the building regulation of each nation has to define fire resistance to prevent building collapse due to high temperatures. In general, the fire resistance of each structural member can be evaluated by two methods. One is prescriptive method that is guided by a specific building regulation containing fire resistance examples or by the application of new examples tested fire experimental procedures. The other is performance based fire engineering design. Being an engineered and scientific method, it utilizes the results obtained from the calculation of fire severities, temperatures of members and so on. The easiest way to evaluate the fire resistance of a steel member is to compare its limiting temperature and maximum temperature. Therefore, constructing the database of the limiting temperatures of structural elements is very important in performance based fire engineering design. This paper is to derive the fire resistance and limiting temperatures of rectangular hollow sections under loads.

Energy Criterion for Fatigue Strength of Wood Structural Members

1996 ◽  
Vol 118 (3) ◽  
pp. 375-378 ◽  
Author(s):  
Jen Y. Liu ◽  
Robert J. Ross
Keyword(s):  
Fatigue Strength ◽  
Good Description ◽  
Energy Criterion ◽  
Element Model ◽  
Cyclic Stress ◽  
Model System ◽  
Model Parameters ◽  
Strength Model ◽  
Structural Members ◽  
Linear Spring

This report describes a mathematical model for fatigue strength of cellulosic materials under sinusoidal loading. The model is based on the Reiner-Weissenberg thermodynamic theory of strength in conjunction with a nonlinear Eyring’s three-element model. This theory states that failure depends on a maximum value of the intrinsic free energy that can be stored elastically in a volume element of the material. The three-element mechanical model, which consists of a linear spring in series with a parallel array of another linear spring and an Eyring dashpot, provides a good description of rheological material properties. The strength model system was able to predict rupture occurrence of polymers and wood structural members under constant and ramp loading with satisfactory results. For sinusoidal loading, the present study shows that the strength model system can predict time at fracture as a function of applied mean stress, amplitude of cyclic stress, and stress frequency. Numerical examples with model parameters evaluated for small Douglas-fir beams are presented.

scholarly journals Civil engineering materials

2021 ◽  
Vol 3 (2) ◽  
pp. 154-172
Author(s):  
Furkan Findik ◽  
Fehim Findik
Keyword(s):  
Civil Engineering ◽  
Construction Materials ◽  
Structural Elements ◽  
Structural Members ◽  
Structural Form ◽  
Bituminous Materials ◽  
Number Of Factors ◽  
Material Choice ◽  
Properties Of Materials ◽  
Materials Used

For any construction project to prove satisfactory, it is essential to understand the properties of materials during both the design and construction phases. It is crucial to consider the economic viability and sociological and environmental impact of a project. During this initial design phase, possible alternative locations and a preliminary assessment of suitable construction materials are taken into account. The decision of which structural form and material choice is most appropriate depends on a number of factors including cost, physical properties, durability and availability of materials. Buildings can contain wood, metals, concrete, bituminous materials, polymers, and bricks and blocks. Some of these can only be used in non-structural elements, while others can be used alone or in combination with structural elements. The actual materials used in the structural members will depend on both the structural form and other factors mentioned earlier. In this study, various materials such as metal, timber, concrete floor and polymer used in civil engineering were examined, the properties and usage areas of these materials were examined.

scholarly journals Strength of Concrete containing Rubber as Partial Replacement of Coarse Aggregate

2020 ◽  
Vol 9 (1) ◽  
pp. 2061-2063
Keyword(s):  
Coarse Aggregate ◽  
Partial Replacement ◽  
Structural Elements ◽  
Structural Members ◽  
Rubberized Concrete ◽  
Cement Concrete ◽  
Coarse Aggregates ◽  
Strength Tests ◽  
Rubber Concrete ◽  
Rubber Aggregates

Effective Waste management is the need of the hour in the world. Solid wastes generated by the industries becomes hazardous as days passes by, used tyres are one such waste material that can affect our environment and people. Rubber tyre wastes can be used as partial replacement for the aggregates. In this study, rubber tyre wastes were used as coarse aggregates. And those rubber aggregates are used as partial replacement of coarse aggregates in the cement concrete (5%, 10%, 15%, 20%). The specimens were subjected to different strength tests as per the standards. It is found that the strength of the concrete is greatly reduced as the percentage of replacement of rubber aggregates is increased. Due to their low strength this type concrete cannot be used for load bearing or structural members. However rubberized concrete can be used for non –structural elements and in future a study can be made whether rubber concrete can be used for pavement blocks.

scholarly journals BUCKLING DELAMINATION IN COMPRESSED NO-TENSION HOMOGENEOUS BRITTLE BEAM-COLUMNS REINFORCED WITH FRP

2021 ◽  
Vol 30 (1) ◽  
Author(s):  
Francesco Marchione
Keyword(s):  
Analytical Solution ◽  
Structural Elements ◽  
Structural Members ◽  
Beam Columns ◽  
Instability Problem ◽  
Frp Reinforcement ◽  
Buckling Delamination ◽  
No Tension Material ◽  
Primary Instability ◽  
Delamination Length

The main issue of this paper is the instability of no-tension structural members reinforced with FRP. This study concerns the instability of FRP reinforcement. The primary instability problem of a compressed element involves the partialization of the inflex section. In particular, in the case of a compressed slender element reinforced on both tense and compressed side FRP delamination phaenomenon could occur on the latter. This entails the loss of the reinforcement effectiveness in the compressed area for nominal load values much lower than material effective strength. Therefore, structural elements or portions thereof which absorb axial components in the direction of the reinforcement may exhibit relatively modest performance with respect to the unreinforced configuration. By employing a no-tension material linear in compression, an analytical solution for FRP buckling delamination length is provided. The main objective of this paper is to provide a simplified tool that allows to evaluate the critical load of the reinforced beam-column and to predict the tension at which delamination and the loss of effectiveness of reinforcement in the compressed area could occur.

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