Epoxy Adhesive Layer Research Articles

Failure investigation of woven scarf-repaired laminates reinforced with nanoparticles: Experimental and numerical investigations

This study explores the efficacy of multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) as nano-reinforcement for the epoxy adhesive layer in scarf joints and 3D scarf-repaired laminates subjected to tensile loading. Experimental characterization of pure epoxy and nanocomposite mechanical properties was validated using the Mori–Tanaka method (incorporating agglomeration effects). A 3D finite element model considering material non-linearity and strain-based damage was employed to investigate joint failure behaviour, validated for 0.5 vol% MWCNT and GNP concentrations. A subsequent parametric study explored the influence of scarf angle, nanoparticle concentration, and patch configuration on 3D repaired specimens. The results suggest a 2.86° scarf angle with a [(+45/−45)]4s patch configuration reinforced with 1 vol% MWCNTs and 0.5 vol% GNPs exhibits the highest tensile strength improvement.

Design, modeling and optimization of an adhesively bonded ring joint with U-section for ceramic cylindrical pressure hull of deep-sea underwater vehicles

The brittleness of ceramic increases the risk of damage or collapse when the ceramic cylindrical pressure hull is directly connected with a rigid part, especially under high hydrostatic pressure. To solve the above problem, this paper systematically explores the design, modeling and optimization of an adhesively bonded ring joint with U-section (ABRJ-U) to avoid the direct connection of the ceramic hull of a small hadal glider, Petrel, with the hemispherical metal end caps. The ABRJ-U is comprised of a U-shaped metal ring, a gasket, and epoxy adhesive layer. To optimize the design parameters, a mechanical model of ABRJ-U is established. The stress tests prove that the model has better efficiency in optimization, but lowered accuracy compared with regular finite element method. Considering the difficulty of obtaining a more accurate theoretical model, the optimization efficiency of regular finite element method is selected for further improvement by integrating the response surface methodology and multi-objective genetic algorithm. According to the optimization results, our optimization method considers the stress calibration of both the adhesive and gasket, simultaneously achieving a 20.8% reduction in the mass of ABRJ-U. The proposed methods also provide valuable reference for the design, modeling, and optimization of other bonded joints.

An effective micro-arc oxidation (MAO) treatment on aluminum alloy for stronger bonding joint with carbon fiber composites

The micro-arc oxidation (MAO) treatment was used in this study to modify aluminum (Al) alloys to improve bond strength with carbon fiber reinforced polymer (CFRP). Various porous surfaces of Al alloy with better hardness, roughness and wetting were created. Void defects were reduced via using resin pre-coating (RPC) technique to guide high-viscosity epoxy into the holes, CNTs fiber bridging was constructed to improve bonding interface and epoxy adhesive layer. Combined treatments of “Na2SiO3 + KOH solution” MAO, RPC and introducing CNTs on Al alloy surface yielded 21.34 MPa, up to 156.1% increment over base strength. Original de-bonding failure on Al alloy surface was altered into dominant fiber tearing failure of CFRP composites, indicating the reinforced bond strength and stronger adhesive joint. MAO was the first try and proved as a feasible treatment for bond strength improvement, which could provide an alternative to manufacture high-performance Al-CFRP composites in industrial production.

Constructing quasi-vertical fiber bridging behaviors of aramid pulp at interlayer of laminated basalt fiber reinforced polymer composites to improve flexural performances

Basalt Fiber Reinforced Polymer (BFRP) composites have huge potential application respects for some civil fields due to enough strength/modulus to weight and low cost by replacing carbon fiber composites. Aiming at the issues in the Resin-Rich Region (RRR) and Interfacial Transition Region (ITR) of fiber reinforced polymer composites, the characteristic Aramid Pulp (AP) fibers with micro-fiber trunk and nano-fiber branches were manufactured into multiple non-woven ultra-thin interleaving at the interlayers of BFRP composites via compression molding to reinforce the flexural strengths and elastic moduli. AP fibers were introduced into RRR to form interleaving at the interlayer, the brittle epoxy adhesive layer was improved and enabled to avoid cracking under a low external load. Free fiber branches of AP were also embedded into BF layer to construct quasi-vertical fiber bridging behaviors in ITR, stronger mechanical interlocking was created to prevent crack propagation along the bonding interface of BF/epoxy. Three-point bending testing results showed the interleaving film with 4 g/m2 AP exhibited the best effect among various areal densities and yielded average 315.75 MPa in flexural strength and 21.38 GPa in elastic modulus, having a 63.4% increment and a 47.1% increment respectively compared with the bases. Overall, the simple and low-cost AP interleaving is confirmed as an effective method in improving interlayer structure and flexural performance of BFRP composites, which may be considered to manufacture high-performance laminated fiber reinforced polymer composites in civil aviation industry.

Mechanical performance of adhesively bonded carbon fiber reinforced boron‐modified phenolic resin plastic‐titanium single‐lap joints at high temperature

AbstractThis article characterized the mechanical performance and failure mode of single‐lap joints (SLJs) of carbon fiber reinforced boron‐modified phenolic resin plastic (CF/BPR) and TC4 titanium alloy by quasi‐static tensile tests at four temperatures (25, 100, 175, and 250°C). The experimental results indicated that the shear strength of SLJs is 10.8 MPa at 25°C, which experiences monotonic drop to 80%, 42.6%, and 18.5% with temperature increase from 100 to 175°C, and to 250°C, respectively. Additionally, there was a transformation in the failure mode from composite material failure to cohesive failure in the adhesive along with the temperature increase. The intralaminar elasticities of CF/BPR were predicted using representative volume element (RVE), and the mechanical properties of three types of bondlines (i.e., the interlamination, interface of CF/BPR and the epoxy adhesive layer) were determined by both experiment and predictive methods. A finite element model taking into account the intralaminar damage of CF/BPR and the cohesive behavior of three bondlines was established. The simulated results showed good consistency with the experimental data for failure prediction, and the mechanical performance and damage propagation of SLJs at different temperatures were discussed. This research provides reference for the design and manufacture of high‐temperature bonded structures.Highlights RVE and degradation factor methods evaluate the elasticity of composite material. Four types of damage behaviors are considered in the established FE model. The SLJs exhibit single or multiple failure modes at different temperatures. The mechanical properties of SLJs severely degraded with increasing temperature.

Robust metallic-based superhydrophobic composite with rigid micro-skeleton structure for anti-icing/frosting

Superhydrophobic coatings with excellent water-repellent property exhibit unique advantages in anti-icing/frosting but suffer from the problem of low mechanical and environmental durability. Although several strategies have been adopted to tackle this issue, developing an equipment-free, low-cost and scalable strategy for the fabrication of robust superhydrophobic coatings remains a technical challenge. Here, we construct a robust superhydrophobic composite with rigid micro-skeleton structure via mild and equipment-free dip-coating method. The prepared composite consists of Cr microparticles confined in epoxy adhesive layer and stearic acid-modified Cu powders, among which the first dip-coating Cr microparticles function as robust micro-skeleton due to their rigid property. Then smaller-sized Cu powders are filled within the micro-skeleton structure to be modified with low-surface-energy coating to provide superhydrophobic property. The rigid micro-skeleton imparts the superhydrophobic composite great durability to resist long-term abrasion, knife scratching, tape-peeling, water jetting tests, acid/saline corrosion, temperature process and UV irradiation. In addition, the as-designed micro-skeleton structure could “lock” various modified nanoparticles (candle soot, SiO2 nanoparticles, recycled rubber particles) to provide the persistently superhydrophobicity. mportantly, the as-prepared superhydrophobic composite could retard the formation of the ice/frost in − 20 ℃, exhibiting a good anti-icing/frosting property and great durability even after cycled anti-icing/frosting test. We believe that this equipment-free, low-cost and scalable design strategy can provide a novel approach for the fabrication of robust superhydrophobic coatings.

Multifunctional superhydrophobic composite with mechanochemical stability for concrete protection

Chemical or electrochemical corrosion of the concrete-based facilities causes potential safety hazards. Endowing the concrete with a commercial superhydrophobic coating with designed surface topography and chemical composition is an effective way to prevent the corrosion of the internal rebars. Although several methods have been adopted to combat the corrosion problem, developing an equipment-free, low-cost and scalable strategy for fabricating a robust superhydrophobic coating on the concrete surface is still a challenge. In this work, a robust superhydrophobic epoxy fixed corundum-silica-polydimethylsiloxane (ECSP) composite is fabricated as the concrete modification coating through an “armour” protection methodology via a facile and low-cost dip-coating process. The as-prepared ECSP composite consists of corundum microparticles (MPs) confined in the epoxy (EP) adhesive layer and silica nanoparticles (SiO2 NPs) modified with a low-surface-energy coating. The corundum MPs with high rigidness and hardness function as a robust, protective “armour” structure, while the polydimethylsiloxane-modified SiO2 NPs reside within the “armour” structure to provide superhydrophobicity. Benefitting from the armoured structure, the ECSP composite coated concrete exhibits an excellent robustness under various harsh conditions including mechanical abrasion, knife scratching, tape-peeling treatment, water jetting, UV irradiation, temperature treatment and chemical corrosion. Importantly, the ECSP composite coating successfully prevents the concrete (with a rebar in it) from the chemical and electrochemical corrosion. The corrosion current density (4.8 × 10−6 A·cm−2) of the ECSP coated concrete is two orders of magnitude lower than that of the unprotected concrete (1.17 × 10−4 A·cm−2), exhibiting its excellent corrosion resistance. Besides, the superhydrophobic ECSP composite coating can retard the formation of ice on the concrete surface at the temperature of −20 °C, exhibiting good anti-icing performance. This work opens a new avenue for the fabrication and application of the multifunctional superhydrophobic coating for concrete protection.

Growing Carbon Nanotubes In Situ Surrounding Carbon Fiber Surface via Chemical Vapor Deposition to Reinforce Flexural Strength of Carbon Fiber Composites.

This study employed novel joint treatments to strengthen the carbon fiber reinforced polymer (CFRP) composites. Vertically aligned carbon nanotubes (VACNTs) were prepared in situ on the catalyst-treated CF surface via the chemical vapor deposition (CVD) method, intertwining into three-dimensional fiber-nets and fully surrounding CF to form an integrated structure. The resin pre-coating (RPC) technique was further used to guide diluted epoxy resin (without hardener) to flow into nanoscale and submicron spaces to eliminate void defects at the root of VACNTs. Three-point bending testing results showed the "growing CNTs and RPC"-treated CFRP composites yielded the best flexural strength, a 27.1% improvement over the specimens without treatment, while the failure modes indicated that the original delamination failure was changed into "flexural failure" with through-the-thickness crack propagation. In brief, growing VACNTs and RPC on the CF surface enabled toughening of the epoxy adhesive layer, reducing potential void defects and constructing the integrated quasi-Z-directional fiber bridging at the CF/epoxy interface for stronger CFRP composites. Therefore, the joint treatments of growing VACNTs in situ via the CVD method and RPC technique are very effective and have great potential in manufacturing high-strength CFRP composites for aerospace applications.

Inherent cohesive failure of epoxy adhesive in carbon-fiber-reinforced plastic composites revealed by micro-tensile testing and finite element analysis

Cohesive failure in the epoxy adhesive layers of carbon-fiber-reinforced plastic (CFRP) joints is incomprehensible because the adhesion interface with almost no covalent bonds is supposed to be the weakest in the joined structure. It is a long-standing unsolved issue that adhesive failure at the interface is a rare case. Cohesive failure in CFRP joints may be caused by micrometer-scale defects in their adhesive layers. In the aviation industry, one of the typical thermosetting molecular systems is a combination of the diglycidyl ether of bisphenol A (DGEBA) adhesive and the tetraglycidyl 4,4′-diaminodiphenylmethane (TGDDM) adherend, both of which are hardened with the 4,4′-diaminodiphenyl sulfone (DDS) curing agent. Eliminating the influence of microdefects, the fracture mechanism was studied using micro-tensile test specimens with gauge dimensions of 10 × 10 × 30 μm3, which were locally extracted from macroscale adhesion blocks. Two cohesive failure modes were predominantly observed with equal probabilities: 0.1–1 μm away from the interface and at the middle of the DGEBA section, except infrequent adhesive failure because of weak bonds. Cohesive failure is demonstrated to be an inherent behavior, which is consistent with the finite-element-method (FEM)-derived stress profiles, provided that the adhesion interface sustains the load stress. A phenomenological model for cohesive failure is proposed, which helps explain the fact that the elastically deformable adhesion interface with the physical bonding due to van der Waals forces is stronger than the adhesive and adherend hardened by both physical and chemical bonding. These findings lead to improvements in the reliability of CFRP components.

Development and implementation of a simultaneous fatigue crack growth test setup for polymeric hybrid laminates

Delamination is a common and highly relevant in-service failure mode of laminated structures. Cyclic mechanical loads superimposed with environmental factors, such as hot-humid air, are most critical. To evaluate the cyclic debonding resistance of polymeric hybrid laminates, fracture mechanics approaches based on double cantilever beam (DCB) specimens are well established. However, conventional fatigue test setups allow for measurement of just one specimen which is rather time consuming. The main objective of this paper was to develop and implement a novel fatigue test setup for simultaneous characterization of multiple DCB specimens. To validate the simultaneous fatigue testing system, steel/epoxy laminates of different number of steel plies and epoxy adhesive layers with or without filler were characterized using the novel fatigue test setup and a conventional electrodynamic test machine. Fatigue crack growth data was fitted by a form of the Hartman-Schijve crack growth equation. To derive a statistically significant threshold value a fitting procedure was employed. A good agreement of the crack growth kinetics data at ambient conditions was obtained confirming the high quality and reliability of the novel simultaneous fatigue test setup. Moreover, reliable data were gathered at the beginning of the displacement–controlled experiments in the instable crack propagation regime, as the displacement amplitude was reached from the first cycle onward. The novel test methodology is of special relevance for development and screening of adhesive formulations.

Effect of Epoxy Structure on Properties of Waterborne Coatings and Electrical Steel Laminates.

Epoxy varnishes are of high relevance to advanced steel laminates for the transformation of electric energy. Structure–property correlations of epoxy varnishes, coil coatings and electrical steel laminates are poorly described. Hence, the main objective of this paper was to develop, implement and evaluate well-defined waterborne model epoxy varnishes for electrical steel laminates, and to elucidate structure–property correlations. Adhesives with systematically varied equivalent epoxy weight (EEW) based on bisphenol-A-diglycidyl ether (DGEBA) were investigated and used to formulate waterborne varnishes. Crosslinking agent dicyandiamide (DICY) was added in an over-stoichiometric ratio. The waterborne model varnishes were prepared by shear emulsification at elevated temperatures. The model varnishes in the A-stage were applied to electrical steel using a doctoral blade. At a peak metal temperature of 210 °C, the coatings were cured to the partly crosslinked B-stage. Coated steel sheets were stacked, laminated and fully cured to C-stage at 180 °C for 2 h. For laminates with an epoxy adhesive layer in the C-stage, glass transition temperatures (TG) in the range of 81 to 102 °C were obtained by dynamic mechanical analysis in torsional mode. Within the investigated EEW range, a negative linear correlation of EEW and TG was ascertained. Presumably, higher EEW of the varnish is associated with a less densely crosslinked network in the fully cured state. Roll peel testing of laminates at ambient and elevated temperatures up to 140 °C confirmed the effect of EEW. However, no clear correlation of roll peel strength and glass transition temperature was discernible. In contrast, fatigue fracture mechanics investigations revealed that hydroxyl functionality and crosslinking density were affecting the crack growth resistance of laminates in a contrary manner. The energy-based fracture mechanics approach was much more sensitive than monotonic peel testing.

Toughening adhesive joints through crack path engineering using integrated polyamide wires

Ensuring the progressivity of failure of adhesively-bonded composite joints is necessary to guarantee safety and to optimize maintenance operations. In our previous work, we proposed a novel surface patterning strategy to stop crack propagation by triggering bridging of adhesive ligaments. However, the brittle failure of classical bridging ligaments still releases a large amount of stored elastic energy, leading to a snap-slip crack propagation or even catastrophic sudden fracture of bonded joints. Such technology could be further improved by integrating ductile structures within the adhesive layer, but the detailed failure mechanisms require systematic investigation. In this work, we integrated thermoplastic polyamide structures within the epoxy adhesive layer of double cantilever beams to guide this transition from brittle failure to a stable softening behavior. Weak polyamide/epoxy adhesion and their embedded area fractions were critical since they affected the damage mechanisms and determined energy dissipation within bonded joints.

Finite element analysis of competitive damage mechanisms of composite scarf adhesive joints by considering thickness effect

Cohesive zone models are demonstrated to fail to predict damage mechanisms of adhesive layer with the increase of thickness, although the load response and ultimate failure strength of adhesive joints are evaluated well to some extent. This paper attempts to explore damage mechanisms of composite scarf adhesive joints with brittle adhesive material under quasi-static loading, where the competitive relationships between the damage behaviors of adhesive layer and the interface debonding between the adhesive layer and composite laminates are investigated. For the epoxy adhesive layer, the damage initiation criteria are developed by considering the hydrostatic pressure, the tension/compression asymmetry and frictional effects, and the damage evolution law is derived using continuum damage mechanics. The bilinear cohesive model and the modified Xu and Needleman’s exponential cohesive model are used to predict the interface debonding between the epoxy adhesive layer and glassy fiber/epoxy composite laminates, respectively. FEA is performed to study two competitive damage mechanisms of composite scarf adhesive joints by discussing the effects of the scarf angle, the thickness of adhesive layer and the shape of cohesive models. Results show that 1. two approaches with/without considering damage mechanisms of adhesive layer can be chosen alternatively within the thickness of adhesive layer 0.5–1.0 mm, by weighing calculation efficiency and precision appropriately; 2. damage features of adhesive layer deserve more attention as the thickness increases beyond 1.0 mm.

Effect of particles on tensile and bending properties of jute epoxy composites

Abstract In this investigation, mechanical properties of composite materials produced from woven jute type were investigated. These composites were produced in the form of epoxy adhesive layers by using hand lay-up method in which aluminum, mica and ceramic particles were added into epoxy as a structural adhesive by 2, 4 and 6 wt%. Samples produced according to ASTM D procedures were subjected to tensile and three point bending loads to examine the effect of the particles. Experimental results were presented in tables and graphs. As a result, it was observed that the tensile and bending failure loads of the composite materials obtained by using the particle reinforced adhesive increased. Also, the biggest rise in tensile strength was achieved with 4 wt% aluminum and the biggest increase in bending strength was observed for 2 wt% aluminum particles.

Development of a fracture-mechanics based fatigue testing method for epoxy/electrical steel laminates with thin adhesive layer

A fatigue fracture mechanics method was developed, implemented and used to characterize the crack kinetics of laminated electrical steel. Tests were carried out on double cantilever beam specimen based on electrical steel sheets and an epoxy adhesive layer with a thickness of just 10 µm. Two different crack length measurement methods based on optical measurement or compliance calculation were evaluated. As validation method specimens with different artificial initial crack length were used. The accuracy is limited to thin and stiff adhesives ensuring a small plastic zone size compared to the crack length. The accuracy of the crack length evaluation methods was higher for the compliance based approach meeting standard specifications at low to intermediate crack length values. The compliance based method was applied to investigate a specimen series varying the pre-curing temperature of the epoxy adhesive systematically. The fatigue tests were performed at ambient condition and 60 °C. At ambient temperature, laminates based on coated electrical steel pre-cured at low to intermediate temperatures revealed rather slow crack propagation rates in comparison to laminates made from coated steel pre-cured at 250 °C. The differences in the stable crack propagation rate of the investigated laminates at ambient conditions were up to two orders of magnitude higher. At 60 °C, the worst performance was also obtained for laminates based on coated steel sheets pre-cured at 250 °C. The failure mode was similar for laminates tested at 23 and 60 °C. While interfacial failure was ascertained for laminates based on coated steel sheets pre-cured at 190 and 250 °C, the better performing laminates made from sheets with epoxy coating pre-cured at 210 or 230 °C exhibited mainly cohesive failure. Hence, adequate pre-curing conditions are of utmost importance for the crack kinetics of adhesively bonded electrical steel.

Effect of Nonwoven Carbon Tissue-Reinforced Epoxy Resin Adhesive Layer on the Single Lap Bonding Strength of Aluminum Alloy Joints.

The present paper provides a solution to enhance the reliability of bonding. The effect of the nonwoven carbon tissue (NWCT) composite adhesive layer on the bonding strength and reliability of aluminum alloy of single lap joints (SLJ) was investigated by embedding NWCT into the epoxy adhesive layer. The bonding strength, Weibull distribution, metallography of cross section, and fracture surface morphology of NWCT specimens were investigated. The results showed that the average bonding strength and Weibull characteristic strength (WCS) of NWCT-reinforced specimen were 16.78 and 17.17 MPa, which increased by 70.2 and 66.7%, respectively, compared with the neat specimen, and the Weibull modulus increased from 11.46 to 22.83, which indicated that NWCT specimens had higher bonding reliability. The mechanism of microcrack formation was obtained by analyzing the cross section of specimen loaded 95% WCS without macroscopic damage. The metallographic section showed that the microcrack of the neat specimen originated from the adhesive–aluminum interface, while the microcracks of the NWCT specimen originated from the interface between short carbon fibers (SCF) and adhesive. Typical failure modes were gained from visual observation and SEM. The failure mode of the neat specimen included more Al–adhesive interface failure, while the NWCT specimen included more internal failure of adhesive–SCFs with the fracture, pullout, peeling, and slippage of SCFs improving the toughness and bonding strength of the adhesive layer. The bridging effect of SCFs in the adhesive layer reinforced by NWCT can even the load and release the stress to improve the bonding reliability.

Possibilities of Increasing Effectiveness of RC Structure Strengthening with FRP Materials.

Modern composite materials based on non-metallic continuous fibres are increasingly used in civil engineering to strengthen building structures. In the strengthening of reinforced concrete (RC) structures, the utilisation of externally bonded fibre-reinforced polymer (FRP) composites is only up to 35% because of the pilling-off failure mechanism. This problem can be solved using pre-tensioned composite laminates. Due to more complex behaviour, the strengthening of structures by means of prestressing technology needs a careful design approach and a full understanding of the behaviour of both the materials and elements. The advantages and risks of the presented technology, which may determine the success of the entire project, will be highlighted in the paper. The possibility of using a flexible adhesive layer in carbon fibre reinforced polymer (CFRP) strengthening applications for flexural strengthening of RC elements, as an innovative solution in civil engineering, will also be presented. Parallel introduction of the flexible adhesive layer (made of polyurethane masses) and a traditional epoxy adhesive layer in one strengthening system was investigated in the laboratory tests. This solution was used for the repair and protection of a previously damaged RC beam against brittle failure.

Analysis on an improved resistance tuning type multi-frequency piezoelectric spherical transducer

The existing piezoelectric spherical transducers with fixed prescribed dynamic characteristics limit their application in scenarios with multi-frequency or frequency variation requirement. To address this issue, this work proposes an improved design of piezoelectric spherical transducers using the resistance tuning method. Two piezoceramic shells are the functional elements with one for actuation and the other for tuning through the variation of load resistance. The theoretical model of the proposed design is given based on our previous work. The effects of the resistance, the middle surface radius and the thickness of the epoxy adhesive layer on the dynamic characteristics of the transducer are explored by numerical analysis. The numerical results show that the multi-frequency characteristics of the transducer can be obtained by tuning the resistance, and its electromechanical coupling coefficient can be optimized by a matching resistance. The proposed design and derived theoretical solution are validated by comparing with the literature given special examples as well as an experimental study. The present study demonstrates the feasibility of using the proposed design to realize the multi-frequency characteristics, which is helpful to improve the performance of piezoelectric spherical transducers used in underwater acoustic detection, hydrophones, and the spherical smart aggregate (SSA) used in civil structural health monitoring, enhancing their operation at the multiple working frequencies to meet different application requirements.

Effects of Epoxy Adhesive Layer Thickness on Bond Strength of Joints in Concrete Structures.

In the construction field, adhesives are frequently used to improve adhesion between two objects. Epoxy adhesives are applied as long-term solutions, improving the bond between repair materials and existing concrete structures. Experimental investigations of the relationship between the thickness of an adhesive layer and its shear strength have been conducted by a number of industries outside of the construction sector. However, that research used metal plates as adherends when determining the shear strengths of epoxy adhesives. Therefore, this study examines epoxy adhesives’ shear strength development when applied to concrete adherends. The test results show that the thickness of the bond layer did affect shear strength development in the epoxy adhesives examined.

Influence of epoxy adhesive layer on impact performance of TiB2-B4C composites armor backed by aluminum plate

Influence of adhesive layer, used to bond ceramic tiles and back plate, on high velocity impact performance of the ceramic/metal composite armor was studied by experimental and numerical investigations. Two types of targets, monolithic ceramic structures and laminated ceramic structures backed by aluminum alloy, with different thicknesses of adhesive layer (0.5 mm, 1.0 mm, 1.5 mm and 2.0 mm) were considered. Results indicated that the size of fractured ceramic was decreased with the increase of adhesive thicknesses. And the size of fragments in the laminated ceramic/aluminum structures with adhesives was smaller than that of in the monolithic ceramic/aluminum structures. A change in crack trajectory were observed at the ceramic/adhesive layer interface of the laminated ceramic composites armor. It showed that the capacity of energy absorption would be improved at the lateral direction, and the failure of the second ceramic plate would be delayed by the change. The penetration depth of the monolithic ceramic/aluminum structures bonded by epoxy resin was found to be greater than that of the armor without adhesive. But the addition of adhesive layer improved the impact performance for the laminated ceramic/aluminum structures. In addition, the depth of penetration was decreased with the increase of adhesive thicknesses for both forms of composite armor. Then simulation results showed that adhesive thickness has little effect on stress wave propagation of inner adhesive layer. Due to the difference of elastic impedance among target plates, the pressure amplitude in different plates was decreased by addition of the adhesive layers, especially for the laminated ceramic/aluminum structures. Lastly, the shear strain and shear strain rate of adhesive layer was decreased with the increase of adhesive thicknesses, which improved the impact performance of laminated composites armor.