ANALYSIS OF BENDING OF COMPOSITE PLATES WITH ACCOUNT FOR THE DIFFERENCE IN RESISTANCE TO TENSION AND COMPRESSION

2021 ◽  
Vol 62 (5) ◽  
pp. 851-860
Author(s):  
I. E. Petrakov ◽  
V. M. Sadovskii ◽  
O. V. Sadovskaya
Keyword(s):  
Composite Plates ◽  
Tension And Compression ◽  
The Difference

Analysis of Stresses in CFRP Composite Plates Drilled with Conventional and Abrasive Water Jet Machining

2013 ◽  
Vol 763 ◽  
pp. 127-143 ◽  
Author(s):  
M. Saleem ◽  
Habiba Bougherara ◽  
L. Toubal ◽  
F. Cénac ◽  
Redouane Zitoune
Keyword(s):  
Fatigue Testing ◽  
Composite Plates ◽  
Water Jet ◽  
Image Correlation ◽  
Initial Surface ◽  
Abrasive Water Jet ◽  
Machining Processes ◽  
Static Tests ◽  
The Difference ◽  
Conventional Machining

The aim of this paper is to analyze the influence of two machining processes on the mechanical behaviour of composite plates under cyclic loading. For this purpose, an experimental study using several CFRP plates drilled with conventional machining and non-conventional machining (abrasive water jet) was carried out. Digital image correlation and static tests using an Instron 4206 tester were performed. In addition, infrared thermography (IR) and fatigue tests were also performed to assess temperature and damage evolutions and also the stiffness degradation. Fatigue results have shown that the damage accumulation in specimens drilled with conventional machining was higher than the abrasive water jet ones. Furthermore, the endurance limit for plates drilled conventionally was approximately 10% higher than those drilled with abrasive water jet. This difference was related to the initial surface integrity after machining induced by the difference in the mechanism of material's removal between the two processes. The difference in surface texture was responsible for the initiation of stress concentration sites as evident from IR camera’s stress analysis. This was confirmed by SEM tests conducted after a destructive sectioning of the specimens before fatigue testing.

Natural Frequencies of Stiffenened and Unstiffened Laminated Composite Plates

2007 ◽  
Author(s):  
M. T. Ahmadian ◽  
T. Pirbodaghi ◽  
M. Pak
Keyword(s):  
Timoshenko Beam ◽  
Degrees Of Freedom ◽  
Natural Frequencies ◽  
Compressive Force ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Composite Plates ◽  
Axial Tension ◽  
Tension And Compression ◽  
Plane Displacement

In this study, the free vibration of laminated composite plates with and without stiffeners subjected to axial loads is carried out using finite element method. The plates are stiffened by laminated composite strip and Timoshenko beam. The plates and the strips are modeled with rectangular 9 noded isoparametric quadratic elements with three degrees of freedom per node and the Timoshenko beam is modeled with linear 2 noded isoparametric quadratic elements with 2 degrees of freedom per node. The effects of both shear deformation and rotary inertia are implemented in the modeling of plate and stiffener. The governing differential equations are obtained in terms of the mid-plane displacement components and shear rotations using Hamilton’s principle. The effects of axial tension and compression loads and stiffeners on the natural frequencies of the plate are investigated. Results indicate the tension loads and stiffeners will increase the natural frequencies while the compression loads reduce the natural frequencies. The buckling force of plate is computed by increasing the absolute value of compressive force until the first natural frequency tends to zero. Results of simple cases are compared with finding in the literature and a good agreement was achieved.

Lamb-Wave Based Damage Detection in Anisotropic Composite Plates

2014 ◽  
Vol 627 ◽  
pp. 1-4 ◽  
Author(s):  
Z. Sharif-Khodaei ◽  
M.H. Aliabadi
Keyword(s):  
Damage Detection ◽  
Lamb Wave ◽  
Lamb Waves ◽  
Composite Plates ◽  
Detection Algorithm ◽  
Damage State ◽  
Anisotropic Composite ◽  
Cfrp Composite ◽  
The Difference ◽  
Imaging Algorithms

Damage detection in anisotropic composite plates based on Lamb wave technique has been investigated. A network of transducers is used to detect barely visible damage caused by impact. A CFRP composite plate has been impacted and tested to verify the proposed damage detection algorithms. The difference in the propagational properties of Lamb waves in the pristine state and the damage state is used through data fusion and imaging algorithms to detect, locate and characterise the damage. The influence of directionality of the velocity on the validity of the detection algorithm is examined and some results are presented.

scholarly journals Mathematical model of the stress-strain state of a rod with an inhomogeneous layered structure

2021 ◽  
Vol 82 (4) ◽  
pp. 14-22
Author(s):  
S. M. Akhmetov ◽  
◽  
M. T. Userbayev ◽  
Zh. U. Iklasova ◽  
A. B. Bolatova ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Layered Structure ◽  
Strain State ◽  
Stress Strain ◽  
Stress Strain State ◽  
Current State ◽  
Tension And Compression ◽  
The Difference ◽  
State Of Research ◽  
Wooden Structures

The stress-strain state (SSS) of a rod with an inhomogeneous layered structure is considered. On the basis of a brief review and analysis of the current state of research of rod systems, the relevance of the study of the SSS of layered-heterogeneous wooden structures is substantiated, taking into account the presence of different resistance of layers to tension and compression. On this basis, the authors solve the problem of determining the SSS of layered-heterogeneous wooden rods in creep conditions, where factors such as humidity and temperature, as well as the difference in the resistance of wood layers to stretching and compression are taken into account. When solving the problem, the mechanical-sorption creep of wood is also taken into account.

scholarly journals Influence of heat treatment and stress state on the functional and mechanical properties of the [001]-oriented single crystals of fenicoalti alloy

2020 ◽  
pp. 132-140
Author(s):  
I.V. Kuksgauzen ◽  
◽  
Y.I. Chumlyakov ◽  
I.V. Kireeva ◽  
V.V. Poklonov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Stress State ◽  
Martensitic Transformation ◽  
Single Crystals ◽  
Maximum Increase ◽  
Β Phase ◽  
Tension And Compression ◽  
Aging Regime ◽  
The Difference

The effect of the γ'- and β-phase particles on the thermoelastic γ-α' martensitic transformation (MT) during cooling/heating and under stress was studied under tension and compression on the [001]-oriented single crystals of Fe-28%Ni-17%Co-11.5%Al-2.5%Ti (at.%) alloy. The effect of the aging regime on the Ms temperature was shown. Maximum increase in the Ms temperature by 100 K was found with the simultaneous precipitation of the γ'- and β-phase particles after two-stage aging of 4+4h at 873 K, in comparison with single-stage aging for 8h. In crystals with γ' and γ'+β-phases particles the difference (asymmetry) of the stresses for the stress-induced γ-α' MT σcr and value α = d σcr/ dT under tension and compression were not observed. The absence of asymmetry of the σ cr and value α = d σcr/ dT are due to close values of the shape memory effect (SME) and superelasticity (SE) under tension and compression. The values of SME and SE were decreased when β-phase particles are precipitated.

scholarly journals Identification of the parameters of the quadratic model of the elastic anisotropic material

2021 ◽  
pp. 3-11
Author(s):  
Ши Тоан Нгуен ◽  
Дмитрий Викторович Христич
Keyword(s):  
Elastic Constants ◽  
Anisotropic Material ◽  
Orthotropic Material ◽  
Composite Plates ◽  
Anisotropic Materials ◽  
Second Order ◽  
Quadratic Model ◽  
Linearly Independent ◽  
Proposed Model ◽  
The Difference

Рассмотрена модель упругости второго порядка для ортотропного материала. Проведенный анализ показывает, что квадратичная часть предложенной модели содержит тринадцать упругих постоянных, из которых девять являются линейно независимыми. Параметры модели определены по данным экспериментов с композитными пластинами. Модель позволяет описывать наблюдаемые в экспериментах нелинейные зависимости между напряжениями и деформациями в процессах растяжения, сжатия и сдвига, а также разносопротивляемость анизотропных материалов. A second-order elasticity model for an orthotropic material is considered. The analysis shows that the quadratic part of the proposed model contains thirteen elastic constants, nine of which are linearly independent. The parameters of the model are determined from the data of experiments with composite plates. The model allows one to describe experimentally observed nonlinear dependences of stresses and strains in the processes of tension, compression, and shear, as well as the difference in resistance of anisotropic materials.

scholarly journals Femoral neck fracture prediction by anisotropic yield criteria

2009 ◽  
pp. 33-41
Author(s):  
Mohamed Tellache ◽  
Martine Pithioux ◽  
Patrick Chabrand ◽  
Christian Hochard
Keyword(s):  
Bone Structure ◽  
Density Measurement ◽  
Transversely Isotropic ◽  
Energy Criterion ◽  
Mineral Density ◽  
Distortion Energy ◽  
Tension And Compression ◽  
Neck Fracture ◽  
Yield Behaviour ◽  
The Difference

The fracture risk due to osteoporosis, is undertaken with Dual-Energy X-ray Absorptiometry (DEXA) which is an average of bone mineral density measurement, without taking into account the bone structure. The objective of this study was an experimental test to solicit the human proximal femurs by a physiological configuration (one leg stance phase of walking). For this, transversely isotropic finite element models were developed from CT scan acquisition. The failure load assessment was insured by anisotropic yield behaviour criteria based on distortion energy criterion (Hill’s criterion) and taking into account the difference between tension and compression yield properties (Tsai–Wu’s criterion). The results found in this study showed the significance part of anisotropic yield behaviour of bone on proximal femur.

Effects of the 3DP process parameters on mechanical properties of polylactic acid part used for medical purposes

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sunthorn Chaitat ◽  
Nattapon Chantarapanich ◽  
Sujin Wanchat
Keyword(s):  
Mechanical Properties ◽  
Gamma Radiation ◽  
Polylactic Acid ◽  
Gamma Ray ◽  
Compressive Load ◽  
Tensile Load ◽  
Test Method ◽  
Content Type ◽  
Tension And Compression ◽  
The Difference

Purpose This paper aims to investigate effect of infill density, fabricated built orientation and dose of gamma radiation to mechanical tensile and compressive properties of polylactic acid (PLA) part fabricated by fused deposit modelling (FDM) technique for medical applications. Design/methodology/approach PLA specimens for tensile and compressive tests were fabricated using FDM machine. The specimens geometry and test method were referred to ASTM D638 and ASTM D695, respectively. Three orientations under consideration were flat, edge and upright, whereas the infill density ranged from 0 to 100%. The gamma radiation dose used to expose to specimens was 25 kGy. The collected data included stress and strain, which was used to find mechanical properties, i.e. yield strength, ultimate tensile strength (UTS), fracture strength, elongation at yield, elongation at UTS and elongation at break. The t-test was used to access the difference in mechanical properties. Findings Compressive mechanical properties is greater than tensile mechanical properties. Increasing number of layer parallel to loading direction and infill density, it enhances the material property. Upright presents the lowest mechanical property in tensile test, but greatest in compressive test. Upright orientation should not be used for part subjecting to tensile load. FDM is more proper for part subjecting to compressive load. FDM part requires undergoing gamma ray for sterilisation, the infill density no less than 70 and 60% should be selected for part subjecting to tensile and compressive load, respectively. Originality/value This study investigated all mechanical properties in both tension and compression as well as exposure to gamma radiation. The results can be applied in selection of FDM parameters for medical device manufacturing.

Optimum Design of Fibre Orientation Angles in Composite Laminate Plates for Minimum Thickness

2010 ◽  
Author(s):  
Rasoul Khandan ◽  
Siamak Noroozi ◽  
Philip Sewell ◽  
John Vinney ◽  
Mohammad Reza Ramazani
Keyword(s):  
Transverse Shear ◽  
Composite Laminate ◽  
Fibre Orientation ◽  
Laminated Composite ◽  
Composite Plates ◽  
Failure Criteria ◽  
Local Optimum ◽  
Minimum Thickness ◽  
Starting Point ◽  
The Difference

Previous studies have shown that composite fibre orientation angles can be optimised for specific load cases such as longitudinal or in-plane loading. However, the methodologies utilised in these studies cannot be used for general analysis of such problems. This research presents a methodology whereby the thickness of laminated composite plates is minimised by optimising the fibre orientation angles for different load cases. Therefore, the effect of transverse shear forces is considered in this study. Simulated annealing (SA), which is a type of stochastic optimisation method, is used to search for the optimal design. This optimisation algorithm has been shown to be reliable as it is not based on the starting point and it can escape from the local optimum points. In accordance with the annealing process where temperature decreases gradually, this algorithm converges to the global minimum. In this research, the Tsai-Wu failure and maximum stress criteria for composite laminate are chosen. Tsai-Wu failure is operationally simple and readily amenable to computational procedures. In addition, this criterion shows the difference between tensile and compressive strengths clearly, through its linear terms. By applying two failure criteria at the same time the results are more reliable. Finally, the numerical results are obtained and compared to the results of previous research with specific loadings to validate the methodology. Additionally the ply angles of composite plate are optimised by considering the effect of transverse shear force and induced twist angles.

Sign in / Sign up

Export Citation Format

Share Document