Investigations on the Influence of High Pressures on the Curing Behaviour and Material Properties of Composite Structures for the Development of a Material Model

2020 ◽  
pp. 313-323
Author(s):  
Nadine Gushurst ◽  
Tim Frerich ◽  
Axel S. Herrmann
Keyword(s):  
Material Properties ◽  
Composite Structures ◽  
High Pressures ◽  
Material Model

Numerical Simulation of Thermoplastic Composite Material by ANSYS

2011 ◽  
Vol 279 ◽  
pp. 181-185 ◽  
Author(s):  
Guo Hua Zhao ◽  
Qing Lian Shu ◽  
Bo Sheng Huang
Keyword(s):  
Numerical Simulation ◽  
Composite Material ◽  
Composite Structures ◽  
Material Model ◽  
General Purpose ◽  
Thermoplastic Composite ◽  
Finite Element Code ◽  
Peek Composite ◽  
Test Result ◽  
Good Agreement

This paper proposes a material model of AS4/PEEK, a typical thermoplastic composite material, for the general purpose finite element code—ANSYS, which can be used to predict the mechanical behavior of AS4/PEEK composite structures. The computational result using this model has a good agreement with the test result. This investigation can lay the foundation for the numerical simulation of thermoplastic composite structures.

Integrally-Stiffened Composite Damage Tolerance Evaluated by Computational Simulation

2001 ◽  
Author(s):  
Christos C. Chamis ◽  
Levon Minnetyan
Keyword(s):  
Material Properties ◽  
Composite Structures ◽  
Failure Modes ◽  
Damage Tolerance ◽  
Epoxy Composite ◽  
Computational Simulation ◽  
Computer Code ◽  
Simulation Design ◽  
Damage Initiation ◽  
Composite Damage

Abstract An integrally stiffened graphite/epoxy composite rotorcraft structure is evaluated via computational simulation. A computer code that scales up constituent micromechanics level material properties to the structure level and accounts for all possible failure modes is used for the simulation of composite degradation under loading. Damage initiation, growth, accumulation, and propagation to fracture are included in the simulation. Design implications with regard to defect and damage tolerance of integrally stiffened composite structures are examined. A procedure is outlined regarding the use of this type of information for setting quality acceptance criteria, design allowables, damage tolerance, and retirement-for-cause criteria.

Oil Film Thickness and Rolling Friction in Elastohydrodynamic Point Contact

1971 ◽  
Vol 93 (3) ◽  
pp. 371-379 ◽  
Author(s):  
R. Gohar
Keyword(s):  
Film Thickness ◽  
Tungsten Carbide ◽  
Material Properties ◽  
High Pressures ◽  
Glass Plate ◽  
Point Contact ◽  
Rolling Friction ◽  
Significant Alteration ◽  
Oil Film ◽  
Rolling Ball

The effect of material properties upon the film thickness in elastohydrodynamic point contact is demonstrated with a rolling ball and plate machine. A 220 fold range of Young’s modulus is employed and a maximum Hertzian pressure of 5 × 105 lb f/in2 is reached. The oil film, which is measured by interferometry, shows no significant alteration at such high pressures, and is also fairly insensitive to the choice of bounding materials. Using a technique similar to that employed by Crook, the rolling friction between a tungsten carbide and a glass plate is found and compared with theory. The effect of spin is investigated and found to be slight.

scholarly journals Reduction of Dynamic Impacts in Block Made of Concrete - Rubber Composites

2018 ◽  
Vol 14 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Maciej Major ◽  
Izabela Major ◽  
Daniela Kuchárová ◽  
Krzysztof Kuliński
Keyword(s):  
Numerical Analysis ◽  
Dynamic Load ◽  
Material Properties ◽  
Material Model ◽  
Damping Factor ◽  
Rubber Composites ◽  
Elastic Deformations ◽  
Real Material ◽  
Additional Protection ◽  
Rubber Concrete

AbstractThe paper presents numerical analysis of block made of three layers: concrete with I-shape rubber pads, space filled with air and concrete with embedded cross rubber pads, respectively. The block is subjected to the dynamic load. To the analysis as rubber the hyperelastic incompressible Zahorski material model was assumed. This material well describes the real material properties in the range of large elastic deformations. Embedded rubber pads provide an additional protection against the transversal dynamic load. ADINA software was utilized to perform numerical analysis of determining the percentage damping factor of rubber-concrete composite in comparison with block made of concrete.

Maximizing the Fundamental Natural Frequency of Triangular Composite Plates

1996 ◽  
Vol 118 (2) ◽  
pp. 141-146 ◽  
Author(s):  
S. Abrate
Keyword(s):  
Natural Frequency ◽  
Material Properties ◽  
Composite Structures ◽  
Natural Frequencies ◽  
Ritz Method ◽  
Laminated Composite ◽  
Composite Plates ◽  
Mode Shapes ◽  
Fundamental Natural Frequency ◽  
Wide Range

While many advances were made in the analysis of composite structures, it is generally recognized that the design of composite structures must be studied further in order to take full advantage of the mechanical properties of these materials. This study is concerned with maximizing the fundamental natural frequency of triangular, symmetrically laminated composite plates. The natural frequencies and mode shapes of composite plates of general triangular planform are determined using the Rayleigh-Ritz method. The plate constitutive equations are written in terms of stiffness invariants and nondimensional lamination parameters. Point supports are introduced in the formulation using the method of Lagrange multipliers. This formulation allows studying the free vibration of a wide range of triangular composite plates with any support condition along the edges and point supports. The boundary conditions are enforced at a number of points along the boundary. The effects of geometry, material properties and lamination on the natural frequencies of the plate are investigated. With this stiffness invariant formulation, the effects of lamination are described by a finite number of parameters regardless of the number of plies in the laminate. We then determine the lay-up that will maximize the fundamental natural frequency of the plate. It is shown that the optimum design is relatively insensitive to the material properties for the commonly used material systems. Results are presented for several cases.

PROGRESSIVE DAMAGE FAILURE ANALYSIS OF POST-BUCKLED COMPOSITE SINGLE-STRINGER PANEL WITH TEFLON INSERTS

2021 ◽  
Author(s):  
VIJAY K. GOYAL ◽  
AUSTIN PENNINGTON ◽  
JASON ACTION
Keyword(s):  
Experimental Data ◽  
Composite Structures ◽  
Laminated Composites ◽  
Compressive Loading ◽  
Weight Ratio ◽  
High Strength ◽  
Material Model ◽  
Stiffened Panels ◽  
Damage Initiation ◽  
Critical Aspects

The high strength-to-weight and stiffness-to-weight ratio materials, such as laminated composites, are advantageous for modern aircraft. Laminated composites with initial flaws are susceptible to delamination under buckling loads. PDA tools help enhance the industry’s understanding of the mechanisms for damage initiation and growth in composite structures while assisting in the design, analysis, and sustainment methods of these composite structures. The global-local modeling approach for the single-stringer post-buckled panel was evaluated through this effort, using Teflon inserts to simulate the defect of damage during manufacturing. This understanding is essential for designing the post-buckled structure, reducing weight while predicting damage initiation location, and addressing a potential design review for future aircraft repairs. In this work, the initial damage was captured with Teflon inserts as the starting configuration; and any reference to the damage initiation refers to any damage beyond the “initial unbonded region.” The effort aims to develop, evaluate, and enhance methods to predict damage initiation and progression and the failure of post-buckled hat-stiffened panels using multiple Abaqus FEA Virtual Crack Closure Technique (VCCT) definitions. Validation of the PDA using the VCCT material model was performed on a large single-stringer panel subjected to compressive loading. The compressive loading of the panel caused the skin to buckle before any damage began to occur locally. In addition, comparisons are made for critical aspects of the damage morphology, such as a growth pattern that included delamination from the skin-stiffener interface to the skin and ply interfaces. When compared against the experimental data produced through the NASA Advanced Composites Project (ACP), the present model captured damage migration from one surface to another, and model validations were ~5% of the experimental data.

Review of material test standardization status for the material qualification of laminated thermosetting composite structures

2020 ◽  
pp. 073168442095810
Author(s):  
Sang Yoon Park ◽  
Won Jong Choi
Keyword(s):  
Composite Materials ◽  
Material Properties ◽  
Composite Structures ◽  
Failure Modes ◽  
Laminated Composite ◽  
Test Methods ◽  
Test Method ◽  
Experimental Comparison ◽  
Laminated Composite Materials ◽  
Design Values

This paper presents a review of recent literature related to the static mechanical testing of thermoset-based carbon fiber reinforced composites and introduces a material qualification methodology to generate statistically-based allowable design values for aerospace application. Although most test methods have been found to be effective in determining the specific material properties by incorporating them into the material qualification and quality control provisions, a full validation to clarify the behavior of thermoset-based laminated composite materials is currently lacking, particularly with regard to the characterization of compressive, in-plane, interlaminar shear, and damage tolerance properties. The present study obtains information on the different types of test method that can be employed within the same material properties, and makes an in-depth experimental comparison based on the past literatures. A discussion on the scope of theoretical analysis involves a description of how the proposed test method can be adequate for obtaining more accurate material properties. This discussion is directly applicable to the assessment of material nonlinearity and the geometrical effect of specimens. Finally, the resulting failure modes and the effect of each material property are studied to aid the understanding of the load distribution and behavior of laminated composite materials.

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