Study of the Design Representation Methods for the Optimization of Multi-Layer Composite Structures

2017 ◽  
Author(s):  
Hongyi Xu ◽  
Junqi Yang ◽  
Ching-Hung Chuang ◽  
Zhenfei Zhan
Keyword(s):  
Composite Structure ◽  
Composite Structures ◽  
Structure Optimization ◽  
Optimization Methods ◽  
Optimization Strategy ◽  
Root Cause ◽  
Design Representation ◽  
Layer Composite ◽  
Low Efficiency ◽  
The Impact

The purpose of multi-layer composite structure optimization is to find the optimal composite layout, such that superior structure performances and lightweight can be achieved. However, the existing optimization methods have a low efficiency when applied to the multi-component, multi-layer composite structure. Such low efficiency is caused by the high dimensionality and the inherent shortcomings of the existing design representation methods. In this work, two composite layout representation methods are compared to better understand their impacts on optimization. The root cause of the low efficiency is identified, and its influences are also quantified using three metrics. Furthermore, a new Representation-Switch Optimization (RSO) strategy is proposed. This strategy improves the search efficiency by switching the design representation methods during the optimization process. Three benchmark studies, two mathematical examples and one real engineering example, are conducted to demonstrate the impact of design representation methods on the optimization results, as well as the effectiveness of the proposed optimization strategy.

A Structural Equation Modeling-Based Strategy for Design Optimization of Multilayer Composite Structural Systems

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Junqi Yang ◽  
Hongyi Xu ◽  
Zhenfei Zhan ◽  
Ching-Hung Chuang
Keyword(s):  
Structural Equation Modeling ◽  
Design Optimization ◽  
Composite Structures ◽  
Structural Equation ◽  
Design Space ◽  
Optimization Methods ◽  
Equation Modeling ◽  
Multilayer Composite ◽  
Design Representation ◽  
Low Efficiency

Design optimization of composite structures is a challenging task due to the large dimensionality of the design space. In addition to the geometric variables (e.g., thickness of each component), the composite layup (the fiber orientation of each layer) also needs to be considered as design variables in optimization. However, the existing optimization methods are inefficient when applied to the multicomponent, multilayer composite structures. The low efficiency is caused by the high dimensionality of the design space and the inherent shortcomings in the existing design representation methods. In this work, two existing composite layup representation methods are investigated to discuss the root cause of the low efficiency. Furthermore, a new structural equation modeling (SEM)-based strategy is proposed to reduce the dimensionality of the design space. This strategy also helps the designers identify the loading mode of each component of the structural system. This strategy is tested in two scenarios of engineering optimization: (1) the direct multidisciplinary design optimization (DMDO), and (2) the metamodeling-based optimization. The proposed methods are compared with the traditional methods on two engineering design problems. It is observed that the design representation methods have a strong impact on the optimization results. The two case studies also demonstrate the effectiveness of the proposed strategy. Furthermore, recommendations are made on the selection of optimization methods for the design of composite structures.

Multifunctional Composite Structures With Integrated Damping Treatments: A Parametric Study

2010 ◽  
Author(s):  
Gre´goire Lepoittevin ◽  
Markus Zogg ◽  
Paolo Ermanni
Keyword(s):  
Composite Structure ◽  
Parametric Study ◽  
Composite Structures ◽  
Composite Laminate ◽  
Vibration Damping ◽  
Design Parameters ◽  
Viscoelastic Core ◽  
Mechanical Performances ◽  
Damping Treatments ◽  
The Impact

A parametric study on composite laminate plates with integrated damping treatment is realized. The goal is to assess the impact of a viscoelastic core on the mechanical performances as well as on the vibration damping efficiency. This work considers as design parameters the damping layer thickness and its position in the laminate lay-up. The obtained results enable to propose a guideline for multifunctional composite structure with intergrated damping treatment.

scholarly journals Behavior to Dynamic Loads of Multi-layer Composite Structures

2019 ◽  
Vol 56 (2) ◽  
pp. 460-465 ◽  
Author(s):  
Victor Geanta ◽  
Ionelia Voiculescu ◽  
Tudor Chereches ◽  
Teodora Zecheru ◽  
Liviu Matache ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Composite Structures ◽  
Basic Element ◽  
Steel Plates ◽  
Maximum Speed ◽  
Backing Plate ◽  
Layer Composite ◽  
Proposed Model ◽  
The Impact ◽  
Empirical Material

The explosive effect and high velocity penetration of the ballistic projectiles of various sizes, design and compositions, on impact with different targets (armors composed of a combination of different metals) are complex. Both practical experiments and mathematical modeling of the phenomena associated to the interaction projectile-target are required to estimate their effect or to design more efficient projectiles and armor. In this study, the basic element of the simulation model is an incendiary projectile of caliber 7.62 mm with medium piercing power, launched with a maximum speed of 750 ms-1 on the multi-material target, which contains 4 different layers assembled into a ballistic cassette made of aluminum. The purpose of this ballistic cassette is to ensure a better contact and handling of multi-layer materials. The proposed model was calculated using mathematical modeling and empirical material constants to describe the nonlinear transitory impact process. Mathematical simulation of the impact between the projectile and target during impact shows that the projectile moves sequentially through the ballistic package, causing perforation, plastic deformation and heating, the resulting fragments being then expelled into the space around the target. The model indicates that the projectile will penetrate the front aluminum plate, as well as the AlCrFeCoNi and steel plates, but will be stopped by the aluminum backing plate. The real impact tests carried out using the ballistic cassette at dynamic impact with the 7.62mm incendiary projectile confirm the model assumptions, which prove the capacity of the composite model to safely stop the projectile.

Research on Dynamic Cumulative Damage Effect of Metal Rubber and Stress Wave Propagation Characteristics of Layered Composite Structure

2021 ◽  
Vol 13 (5) ◽  
pp. 981-990
Author(s):  
Youchun Zou ◽  
Chao Xiong ◽  
Junhui Yin ◽  
Kaibo Cui ◽  
Huiyong Deng ◽  
...  
Keyword(s):  
Stress Wave ◽  
Composite Structure ◽  
Composite Structures ◽  
Impact Resistance ◽  
Layered Composite ◽  
Damage Effect ◽  
Stress Wave Propagation ◽  
Metal Rubber ◽  
Layered Composite Structures ◽  
The Impact

The development of protective materials and structures is of great significance for improving the impact resistance, penetration resistance and spalling resistance of military equipment. At present, the layered composite structure has been widely used due to its good protective performance. In this paper, a special elastic porous material-metal rubber (MR) with excellent cushioning and damping properties was used to prepare high-performance layered composite structures. To begin with, the dynamic mechanical response and the dynamic cumulative damage effect of MR were studied through Split-Hopkinson Pressure Bar (SHPB) tests. Then, the failure form and stress wave propagation characteristics of the layered composite structures were investigated through SHPB tests and finite element method. The results show that repeated impacts can enhance the compactness of MR, thereby increasing the ultimate bearing capacity and energy absorption capacity, which is beneficial for MR to resist repeated impacts. The MR in composite structures can reduce ceramic damage, attenuate stress wave and smooth stress distribution. The titanium alloy on the back of the ceramic will aggravate the damage of the ceramic, and ultra-high molecular weight polyethylene on the back of the ceramic provides cushioning for the ceramic. Therefore, the impact resistance of the composite structure can be improved by adding MR and the reasonable arrangement of materials, and the SiC/UHMWPE/MR/TC4 composite structure has relatively reasonable stress distribution and better protection performance.

The Effect of Nano-Sized Air Bubbles on the Mechanical Properties and Natural Frequencies of a Multi-Cracked Composite Bar

2017 ◽  
Vol 30 ◽  
pp. 65-84 ◽  
Author(s):  
Ahmad Al-Maharma ◽  
Naser Al-Huniti
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Composite Structure ◽  
Hybrid Composite ◽  
Composite Structures ◽  
Natural Frequencies ◽  
Volume Fraction ◽  
Multiple Cracks ◽  
Air Bubbles ◽  
The Impact

In this research, the effect of nanosized air bubbles embedded within carbon nanotubes (CNTs) coated by various thicknesses of alumina (Al2O3) reinforced epoxy resin based composite on the natural frequencies of a multi-cracked bar is investigated in details. The impact of cracks’ locations and depths within the hybrid composite structure on the natural frequency profiles is investigated. The volume fraction of CNTs is fixed to 0.5 wt. % due to the significant improvements reported in the literature when the composite is reinforced with this volume fraction of CNTs. The results of the multi-scale finite element analysis are verified by comparing with previous studies and a good agreement is shown relating to the longitudinal natural frequencies. The results of the research show that the dynamic response of cracked bar is highly sensitive to the volume fractions of nanosized air bubbles located within the composite. The results of the study supported the hypothesis that the nanosized air bubbles can be used to reduce the weight of heavy composite structures along with using of suitable coatings to improve the mechanical properties of the hybrid composite. Furthermore. The results of the study can be employed to detect multiple cracks located within similar structures like wind turbine blade (WTB) fabricated from a hybrid composite structure composed of carbon fiber reinforced modified epoxy resin which contains nanosized air bubbles and CNTs nanofillers coated by Al2O3 at different thicknesses.

scholarly journals TECHNOLOGICAL ASPECTS OF CREATING A FIBER-OPTIC NON-DESTRUCTIVE TESTING OF SANDWICH COMPOSITE STRUCTURES

2019 ◽  
pp. 24-29 ◽  
Author(s):  
M. Yu. Fedotov ◽  
O. N. Budadin ◽  
S. O. Kozel’skaya
Keyword(s):  
Control System ◽  
Composite Structure ◽  
Optical Method ◽  
Composite Structures ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Layer Composite ◽  
Non Destructive

The results of research on the formation of the system of built-in non-destructive testing of linings of composite three-layer structures by an optical method using fiber-optic sensors based on fiber Bragg gratings are presented. The features of creating an input/output zone for fiber-optic sensors as applied to three-layer composite structures are studied. Recommendations for ensuring the integrity and optimal functioning of the fiber-optic monitoring system as applied to a real three-layer composite structure are formulated. The following is shown. The process of creating an integrated control system of three-layer composite structures by an optical method using integrated fiber-optic sensors includes a number of operations to form a topology and to ensure the output of fiber-optic sensors from composite claddings in a single technological cycle of manufacturing the structure according to the standard technological process without significantly adjusting it, which is extremely important in relation to serial technologies. When developing the technology of integrating fiber-optic sensors into a three-layer composite structure, it was experimentally shown that from the point of view of survivability and preservation of the efficiency of the embedded control system, it is necessary to fulfill a number of requirements for the placement and output of fiber-optic sensors taking into account the characteristics of manufacturing, machining, and operation designs. Thus, it is advisable to place fiber optic sensors in the casings at least 5 mm from the intended edge of the structure, at least 2 layers from the outer surface of the structure and not less than 5 layers from the honeycomb core. The fiber bend radius should be at least 30 mm to prevent mechanical burst and sharp bending of the signal when it is bending. Fiber optic sensors are recommended to be placed between layers with a reinforcement scheme in the direction of the fiber optic sensor, however placement is also allowed between the fiber sensors and one layer with a different direction of reinforcement, while in order to prevent fractures, computation fiber optic sensors overlap is unacceptable, thus, between crossover fiber-optic sensors must be at least 2 layers of prepreg.

scholarly journals Seismic Behavior of Steel-Concrete Composite Structures

2019 ◽  
Vol 9 (2) ◽  
pp. 4721-4726
Keyword(s):  
Composite Structure ◽  
Composite Structures ◽  
Seismic Behavior ◽  
Shear Connector ◽  
The Impact ◽  
Direct Investigation ◽  
Numerical Examination

Steel-Concrete composite individuals are an intriguing alternative for auxiliary originators, yet the dependability of plan strategies both on account of gravity and seismic burdens is in persistent advancement. Composite steelconcrete design gives a noteworthy economy through decreased materials and quicker development, such framework utilizes each kind of part in the most proficient way to expand the basic and financial advantages. In this undertaking, hypothetical, numerical perspectives and applications concerning the seismic conduct of steel-concrete composite structures are to be dissected. The intrigue has been concentrating around there on the capacity of composite encircled structures to disseminate seismic vitality by methods for inelastic disfigurements with the goals to: (1) Apply non-direct investigation strategies to assess building execution. (2) The chief highlights influencing the seismic reaction of composite edges. (3) A numerical examination has been direct to research the impact of composite conduct of the structures. (4) A limited component modular has been create to represent the dynamic conduct of composite structure and (5) The impact of shear connector on the conduct of composite encircled structure in seismic stacking

FIRE RESISTACE OF SHEAR CONNECTORS FOR COMPOSITE BEAMS

2020 ◽  
Vol 92 (6) ◽  
pp. 59-65
Author(s):  
G.P. TONKIH ◽  
◽  
D.A. CHESNOKOV ◽  
◽  
Keyword(s):  
Fire Resistance ◽  
Composite Structure ◽  
Composite Structures ◽  
Composite Beams ◽  
Design Codes ◽  
Connection Strength ◽  
Shear Connectors ◽  
Shear Connection ◽  
Capacity Reduction ◽  
Russian Research

Most of Russian research about composite structure fire resistance are dedicated to the composite slab behavior. The composite beams fire resistance had been never investigated in enough volume: the temperature evaluation within the scope of the actual Russian design codes leads to the significant reduction in the shear connection strength. Meanwhile, there no correlation between the strength decreasing and type of the shear connection. The article provides an overview of the relevant researches and offers some approaches which could take into account bearing capacity reduction of the shear connectors within composite structures design.

scholarly journals An efficient approach to reliability-based topology optimization for the structural lightweight design of planar continuum structures

2021 ◽  
Vol 37 ◽  
pp. 270-281
Author(s):  
Fangfang Yin ◽  
Kaifang Dang ◽  
Weimin Yang ◽  
Yumei Ding ◽  
Pengcheng Xie
Keyword(s):  
Topology Optimization ◽  
Lightweight Design ◽  
Integrated Design ◽  
Optimization Methods ◽  
Filter Function ◽  
Continuum Structures ◽  
Performance Indexes ◽  
Reliability Method ◽  
Economic Indexes ◽  
The Impact

Abstract In order to solve the application restrictions of deterministic-based topology optimization methods arising from the omission of uncertainty factors in practice, and to realize the calculation cost control of reliability-based topology optimization. In consideration of the current reliability-based topology optimization methods of continuum structures mainly based on performance indexes model with a power filter function. An efficient probabilistic reliability-based topology optimization model that regards mass and displacement as an objective function and constraint is established based on the first-order reliability method and a modified economic indexes model with a composite exponential filter function in this study. The topology optimization results obtained by different models are discussed in relation to optimal structure and convergence efficiency. Through numerical examples, it can be seen that the optimal layouts obtained by reliability-based models have an increased amount of material and more support structures, which reveals the necessity of considering uncertainty in lightweight design. In addition, the reliability-based modified model not only can obtain lighter optimal structures compared with traditional economic indexes models in most circumstances, but also has a significant advantage in convergence efficiency, with an average increase of 44.59% and 64.76% compared with the other two reliability-based models. Furthermore, the impact of the reliability index on the results is explored, which verifies the validity of the established model. This study provides a theoretical reference for lightweight or innovative feature-integrated design in engineering applications.

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