The in situ ply elasticity and strength in laminated composites

2020 ◽  
Author(s):  
A.I. Oleinikov ◽  
T.A. Kuzmina
Keyword(s):  
Strength Characteristics ◽  
Compression Tests ◽  
Thin Walled Structures ◽  
Calculation Results ◽  
Working Together ◽  
Real Behavior ◽  
Thin Walled ◽  
Design Calculations ◽  
Direct Tensile

When calculating thin-walled structures made of layered polymer composite materials (PCM), data obtained as data obtained from testing a corresponding separately cured unidirectional sheet is accepted as the elastic-strength characteristics of their monolayers. Properties of such sheet significantly differ from the characteristics of the monolayer polymerized and working together with adjacent layers of different orientations as part of a composite package. The article presents the results of solving the problem of determining the elastic and strength characteristics of monolayers according to the data of direct tensile — compression tests of PCM samples from witness parts. It considers PCM which monolayers have similar or diverse characteristics. Formulas are given for calculating the mechanical properties of monolayers as part of a multidirectional composite package. Comparison of calculation results with test data is carried out. The use of the actual characteristics of monolayers makes it possible to calculate the real behavior of the PCM in the structure, to link its verification and design calculations.

scholarly journals Comparative calculation of optimal parameters of channel bent and bent closed profiles

2019 ◽  
Vol 15 (6) ◽  
pp. 415-432
Author(s):  
Alexander S. Marutyan
Keyword(s):  
Technical Solution ◽  
Optimal Parameters ◽  
Design And Optimization ◽  
Comparative Calculation ◽  
Thin Walled Structures ◽  
Riveted Joints ◽  
Composite Section ◽  
Thin Walled ◽  
Design Calculations ◽  
Technical And Economic Indicators

Relevance. A new technical solution for channel bent closed profiles (BCP), distinguished by a composite section and related to light steel thin-walled structures (LSTWS), which are distinguished by high technical and economic indicators and massive demand in industrial and civil construction, is presented. The main results of the comparative calculation of the optimal parameters of bent channels and channel horizontal bending sections are also given. Aim of the research. The purpose of the study is to show that the characteristics of LSTWS can be further improved by shaping modification profiles, combining in its composite section straight and round outlines of closed and open loops. Methods. Through experimental design and optimization and design calculations of channel profiles, their new technical solution has been developed, the originality of which is confirmed by patent examination. Results. Channel BCP consists of two tubular shelves and one wall of double thickness. For its manufacture without welded, bolted or riveted joints, the outer and inner blanks are made along the entire length with serrated longitudinal edges, the teeth of which are staggered relative to each other and mutually bent in grooves after closing a bent profile along its shelves. The bends of the gear mounts increase the collapse thickness, provide an increase in local stability and shear strength of the thin-walled elements, and also allow not to reduce the design sections. A comparative calculation of the optimal parameters of bent channels and channel bending sections for bending showed that in the first of them the strength is maximum when the ratio of the width and height of the cross section is 1/6, and in the second - 1/5.68.

scholarly journals I-shaped bent closed profiles with tubular shelves and calculation of the optimal layout of their composite sections

2020 ◽  
Vol 16 (5) ◽  
pp. 334-350
Author(s):  
Alexander S. Marutyan
Keyword(s):  
Technical Solution ◽  
Optimal Layout ◽  
Design And Optimization ◽  
Thin Walled Structures ◽  
Riveted Joints ◽  
Composite Section ◽  
Outer Pair ◽  
Thin Walled ◽  
Design Calculations ◽  
Technical And Economic Indicators

I-shaped bent closed profiles with tubular shelves are distinguished by a composite section and related to light steel thin-walled structures (LSTWS), which are characterized by high technical and economic indicators and mass demand in industrial and civil construction, which determines the relevance of the development of their new technical solutions. The aim of the work - to show that the characteristics of LSTWS can be further improved by forming profiles, combining straight and round outlines of closed and open circuits in a composite section. Methods. New technical solution, the originality of which is confirmed by patent examination, has been developed through experimental design and optimization and design calculations of I-shaped profiles. The calculation of the optimal bending layout of the composite sections of I-shaped profiles of horizontal billets from sheet blanks, identical and unequal in thickness, including bisteel modifications, is made. Results. The I-shaped bent closed profiles consists of two tubular shelves and one wall of double thickness. For its manufacture without welded, bolted or riveted joints, the outer pair and inner pair blanks are made along the entire length with serrated longitudinal edges, the teeth of which are staggered relative to each other and mutually bent in grooves after closing a bent profile along its shelves. The bends of the gear mounts increase the collapse thickness, provide an increase in the local stability and shear strength of the thin-walled elements, and also allow not to reduce the design sections. The calculation of the optimal layout of I-shaped profiles horizontal bend for bending showed that its strength is maximum when the ratio of the width and height of 1/5.2 and equal thicknesses of shelves and walls.

scholarly journals A Unified Strength Model of Asphalt Mixture Considering Temperature Effect

2021 ◽  
Vol 8 ◽  
Author(s):  
Guoping Qian ◽  
Hui Yang ◽  
Xi Li ◽  
Huanan Yu ◽  
Xiangbing Gong ◽  
...  
Keyword(s):  
Asphalt Mixture ◽  
Tensile Tests ◽  
Strength Characteristics ◽  
Effect Of Temperature ◽  
Engineering Practice ◽  
Strength Model ◽  
Compression Tests ◽  
Shear Property ◽  
Different Temperatures ◽  
Direct Tensile

The strength characteristics of asphalt mixture is crucial for the design and construction of asphalt roads. A strength model considering the effect of temperature is presented in this paper based on unified strength theory (UST). Firstly, direct tensile tests, uniaxial compression tests and anti-shear property tests of asphalt mixture were carried out respectively at different temperatures. Key mechanical parameters were obtained, including tensile strength (σt), compressive strength (σc) and shear strength (τ0) at different temperatures. Besides, the temperature sensitivity of σt, σc and τ0 was systematically analyzed. The results showed that the UST parameters of tensile-compression strength ratio α and failure criterion parameter b have a linear relationship with temperature t. A theoretical model to describe strength characteristics with the temperature of asphalt mixture was developed finally. The developed model was validated via applicability analysis. and it will provide theoretical support for the study of strength characteristics of asphalt mixture and engineering practice.

scholarly journals Curved closed profiles and calculation of their optimal parameters

2019 ◽  
Vol 15 (1) ◽  
pp. 33-43
Author(s):  
Alexander S Marutyan
Keyword(s):  
Shear Strength ◽  
Technical Solution ◽  
Developmental Studies ◽  
Optimal Parameters ◽  
Thin Walled Structures ◽  
Riveted Joints ◽  
Thin Walled ◽  
Design Calculations ◽  
Technical And Economic Indicators ◽  
Patent Examination

Relevance. A new technical solution of bent-closed profiles relating to light steel thin-walled structures (LSTS), which have high technical and economic indicators and are widely used in industrial and civil construction, is presented. Aim of the research. The characteristics of thin-walled structures can be further enhanced by shaping the modification of profiles, combining in its composition the outlines of closed and open outlines. Methods. By means of developmental studies and optimization and design calculations for bent-closed profiles, their new technical solution was developed, the originality of which was confirmed by patent examination. Results. New curved closed profiles (CCP) consist of a tubular part of a single thickness and a double-thickness rib. For their manufacture without welded, bolted or riveted joints, the sheet blank is made along the entire length with serrated longitudinal edges, the teeth of which are arranged relative to each other in a staggered manner and mutually bent in grooves between themselves after the curved profile is closed along its edge. The bends of the gear fasteners increase the thickness of the collapse and provide an increase in the shear strength of the joints of thin-walled elements. With equal dimensions in height and width of the CCP, they are optimized by the criterion of uniform stability, which is the same from the plane and in the plane of the supporting structure. Additionally, a series of pentagonal, triangular and trapezoidal profiles are presen- ted, in which the lateral faces are inclined relative to the vertical at angles of 45 and 60 degrees.

Quasi-static Compressive Properties and Behavior of Single-cell Miura Origami Column Fabricated by 3D Printed PLA Material

2020 ◽  
Vol 3 (2) ◽  
pp. 66-73
Author(s):  
Farid Triawan ◽  
Geraldy Cahya Denatra ◽  
Djati Wibowo Djamari
Keyword(s):  
Single Cell ◽  
Peak Stress ◽  
Absorption Capacity ◽  
Compression Tests ◽  
Compressive Properties ◽  
Folding Pattern ◽  
Column Structure ◽  
Thin Walled ◽  
And Behavior ◽  
Initial Peak

The study of a thin-walled column structure has gained much attention due to its potential in many engineering applications, such as the crash box of a car. A thin-walled square column usually exhibits high initial peak force, which may become very dangerous to the driver or passenger. To address this issue, introducing some shape patterns, e.g., origami folding pattern, to the column may become a solution. The present work investigates the compressive properties and behavior of a square box column structure which adopts the Miura origami folding pattern. Several test pieces of single-cell Miura origami column with varying folding angle and layer height are fabricated by a 3D printer. The filament is made of Polylactic Acid (PLA), which is a brittle material. Then, compression tests are carried out to understand its compressive mechanical properties and behavior. The results show that introducing a Miura origami pattern to form a thin-walled square column can dramatically lower down the initial peak stress by 96.82% and, at the same time, increase its ductility, which eventually improves the energy absorption capacity by 61.68% despite the brittle fracture behavior.

Frame-Monolithic Technology of Construction of Low-Rise Buildings Made of Foam Gypsum and Steel Thin-Walled Structures

2018 ◽  
Vol 762 (8) ◽  
pp. 36-39 ◽  
Author(s):  
B.G. BULATOV ◽  
◽  
R.I. SHIGAPOV ◽  
M.A. IVLEV ◽  
I.V. NEDOSEKO ◽  
...  
Keyword(s):  
Thin Walled Structures ◽  
Thin Walled

scholarly journals Hot Workability of 300M Steel Investigated by In Situ and Ex Situ Compression Tests

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 880 ◽  
Author(s):  
Rongchuang Chen ◽  
Haifeng Xiao ◽  
Min Wang ◽  
Jianjun Li
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Hot Working ◽  
Ex Situ ◽  
Lower Strain Rate ◽  
Hot Workability ◽  
Compression Tests ◽  
300M Steel ◽  
Lower Strain

In this work, hot compression experiments of 300M steel were performed at 900–1150 °C and 0.01–10 s−1. The relation of flow stress and microstructure evolution was analyzed. The intriguing finding was that at a lower strain rate (0.01 s−1), the flow stress curves were single-peaked, while at a higher strain rate (10 s−1), no peak occurred. Metallographic observation results revealed the phenomenon was because dynamic recrystallization was more complete at a lower strain rate. In situ compression tests were carried out to compare with the results by ex situ compression tests. Hot working maps representing the influences of strains, strain rates, and temperatures were established. It was found that the power dissipation coefficient was not only related to the recrystallized grain size but was also related to the volume fraction of recrystallized grains. The optimal hot working parameters were suggested. This work provides comprehensive understanding of the hot workability of 300M steel in thermal compression.

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