Li Chen

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Verified

Li verified their affiliation via an institutional email.

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• Ph.D
• Professor at Southeast University

Concrete exhibits complex failure behavior under explosive or ballistic impact loads. Numerical research methods play a crucial role in revealing the propagation of stress waves, the evolution of cracks, the mechanisms of structural failure, and in conducting protective design. However, as a typical strain-softening material, concrete shows signifi...

Concrete exhibits complex failure behavior under the action of explosion or ballistic impact loads. Numerical research methods play an important role in revealing the propagation laws of stress waves, the evolution process of cracks, the failure mechanism of structures, and in carrying out protective design. As a typical strain-softening material,...

As a crucial component of urban lifeline projects, shallow-buried gas pipelines pose a significant threat to society and people's lives, as well as property in the event of a leakage accident. To investigate the diffusion mechanism of gas leakage out of pipelines, the CFD method is employed to establish a validated numerical model for gas diffusion...

To determine the minimum safety distance between explosive storage caves in Class IV wall rocks, a developed refined finite element (FE) model was established on the basis of fully verifying a constitutive model for high strain rate materials. The FE model was subsequently validated by comparing the calculated minimum safety distances with those sp...

This paper investigates the effect of nonlinear thermal radiation on SWCNT-TiO 2 and MWCNT-CoFe 2 O 4 nanoparticles suspended in a water-based hybrid nanofluid, flowing past rotating disks. The study employs the Cattaneo-Christov heat flux model to capture the influence of non-Fourier heat conduction. The rotational motion of the disks generates th...

Steel-fiber-reinforced concrete (SFRC) has replaced traditional concrete in the construction sector, improving fracture resistance and post-cracking performance. However, extreme temperatures degrade concrete's material characteristics including stiffness and strength. The construction industry increasingly embraces machine learning (ML) to estimat...

The evolution of damage and failure modes of concrete under blast or impact loads are the outcomes of stress wave propagation. The stress state at a point within the concrete changes instantaneously with time and space. Establishing a constitutive model that can cover the nonlinear behavior of materials under complex loading paths and histories is...

Ultra-high molecular weight polyethylene (UHMWPE) laminates represent the most weight-efficient industrial fiber-reinforced resin-based composite material for ballistic protection. To comprehensively understand the anti-penetration mechanism and quantify the anti-penetration performance of UHMWPE laminates, theoretical, experimental, and equation-f...

The recent increase in blast/bombing incidents all over the world has pushed the development of effective strengthening approaches to enhance the blast resistance of existing civil infrastructures. Engineered geopolymer composite (EGC) is a promising material featured by eco-friendly, fast-setting and strain-hardening characteristics for emergent s...

Using split Hopkinson pressure bar (SHPB) to carry out the Brazilian disk test, for the calculation of the splitting tensile strain rate of the specimen, the method in the existing literature only considers the influence of the tensile stress, while in the actual splitting tensile process, the combined effect of compressive stress and tensile stres...

In this paper, eleven high-strength steel tube confined self-stressing concrete (HSTCSC) short columns were tested to study their strengthening mechanism and axial compression performance. The effects of different material strengths, cross-section types, and hollow ratios on the axial mechanical properties of the HSTCSC short columns were investiga...

Split Hopkinson pressure bar (SHPB) tests are popular in calibrating material models at high strain rates under the assumption of constant strain rates. Nonetheless, numerous strain rates obtained from the SHPB test cannot be approximated as constant. Here, the constant assumption is discarded and a new calibration approach with history data is pro...

To further reveal the failure mechanisms of thick ultra-high molecular weight polyethylene (UHMWPE) laminates, field firing tests were conducted for 10-, 20-, and 30-mm thick laminates against 12.7-mm calibre wedge-shaped fragment simulated projectiles at high velocities between 450 and 1200 m/s. The ballistic performance, deformation process, and...

The U-shaped ribs stiffened plates are widely used in civil and marine engineering structures for their high bending resistance performance. Moreover, these structures may be exposed to blast scenario especially terrorist and accidental explosions. Based on this background, this investigation carried out a study on the damage modes and the damage m...

The high cost and long consuming time of field blast test result in that the experimental study on the blast performance of reinforced concrete (RC) column subjected to blast loads and axial loading is limited in the previous study which focuses on the numerical investigation. As the critical reference which is utilized to verify the accuracy of th...

Cost and safety are important considerations when designing the thickness of a protective reinforced concrete shelter. The blast perforation limit (BPL) is the minimum concrete shelter thickness that resists perforation under blast loading. To investigate the influence of the depth of embedment (DOE) and length-to-diameter ratio (L/D) of an explosi...

Lately, explosions with a large TNT equivalent have occurred with alarming frequency causing severe structural damage. The damage suffered by these structures has been exacerbated by the ground shock generated during these large equivalent explosions. The aim of this work is to study the ground-shock propagation behaviors, the areas affected by the...

Concrete shrinkage usually results in the decrease in bearing capacity, durability and impact resistance of Concrete-Filled steel tube (CFST) structures during its service life. High strength expansive concrete (HSEC) is recently developed to deal with the shrinkage cracking in CFST structures. In this study, dynamic compressive tests and dynamic s...

With the completion of the subsea immersed tunnel of the Hong Kong–Zhuhai–Macao Bridge (HZMB), the tunnel structure in a closed environment for a long time will inevitably be threatened by sudden extreme accidents such as car accidents and car bombs. However, intensive research efforts have been devoted to understanding their performance under serv...

The corrugated steel–concrete–steel (CSCS) panels have considerable potential for resisting blast loads. It replaces a flat steel plate of steel-concrete-steel (SCS) panel with a corrugated steel plate on the protected side. In this study, a finite element model (FEM) of the CSCS panel was developed on the LS-DYNA and validated by the blast test re...

In this study, long and thin cylindrical charges were partially embedded in ultra-high-performance concrete (UHPC) and normal-strength concrete (NSC) slabs to investigate the damage characteristics of UHPC slabs subjected to explosions by conventional weaponry. The sizes of ejection and spalling craters were recorded after the experiment to compare...

To increase the blast resistance of reinforced concrete or steel–concrete composite structures with long span, an innovative prestressed steel-grouting material composite beam with a hollow web is proposed. In the beam, the flange is filled with grouting material, and an I-type steel web is used to strengthen the shear capacity, and a prestressed t...

This paper develops a novel three-dimensional (3D) mesoscale modelling approach to study the mechanical responses of coral sands under quasi-static and dynamic compressive loading. A series of algorithms were developed to generate the 3D random particle models with controllable shape and size configurations to simulate the coral sands with random s...

Due to the lack of reliable dynamic shear test technology, there are few studies on dynamic pure shear performance of concrete materials. Based on the one-dimensional stress wave propagation theory, a large-scale torsional split Hopkinson Tube (LTSHT) with an outer diameter of 110 mm was developed. The LTSHT comprises a bearing system, an axial dri...

When an explosion occurs close to or partially within the face of a concrete structure, fragments are rapidly launched from the opposite face of the structure owing to concrete spalling, posing a significant risk to nearby personnel and equipment. To study the lead fragment velocity of ultra-high-performance concrete (UHPC), partially embedded expl...

Structural damage is significantly influenced by the various parameters of a close-in explosion. To establish a close-in blast loading model for cylindrical charges according to these parameters, a series of field experiments and a systematic numerical analysis were conducted. A high-fidelity finite element model developed using AUTODYN was first v...

In this study, the dynamic mechanical properties of hybrid fiber reinforced concrete (HFRC) are analyzed with respect to failure mode, dynamic increase factor (DIF), and peak strain by means of a SHPB testing apparatus. The factors that influence the dynamic mechanical properties include fiber type and fiber content. It is concluded that the best d...

Explosion craters on the ground surface induced by contact or near-field explosions have important implications, which can be used to assess blast consequences, guide the design of the explosion, or develop a protective strategy. In this study, to understand the crater characteristics induced by the contact explosion of large weight explosives, fou...

Gabion walls are considered to be novel, easy-to-transport, and rapidly deployable blast walls. They are widely used to protect military and civilian personnel and equipment in a variety of settings, such as humanitarian and peacekeeping operations. To study the protective effects of gabion wall against blast waves from large TNT-equivalent explosi...

The use of coral aggregate concrete (CAC) as a novel construction material has attracted significant attention for the construction of reef engineering structures. To investigate the static splitting-tensile behaviors of CAC under the influence of two factors, namely specimen geometry and bearing strip size, a three-dimensional (3D) mesoscale model...

In order to investigate the damage modes and residual bearing capacity of strand stay cables subjected to explosions, an experimental study including field blast tests on eight 15.7-7 strand stay cable specimens following by axial tensile tests on the blast-damaged strands were carried out. The damage modes of the strand stay cable specimens under...

U-shaped stiffeners stiffened plates subjected to blast loads were investigated in the study. Field blast experiments were performed, and a fine finite element (FE) model was constructed and validated by the experimental results. Four damage modes of the stiffened plates were discovered by parametric analysis: (I) large plastic deformation, (II) pa...

Shape memory alloys (SMAs) are widely employed in buildings and bridges as energy dissipation devices because of their superelasticity, shape memory, fatigue resistance, and high damping performance. In this study, SMA plates were fabricated into a shear device as a seismic structure. To understand the seismic performance of the SMA plate, an exper...

Ultra-high molecular weight polyethylene (UHMWPE) is widely used as bulletproof material, but it has evident temperature sensitivity, which can lead to the fluctuation of impact resistance. To explore the effect of temperature on the ballistic performance of UHMWPE laminates, ballistic experiments were conducted at different temperatures of −20, 10...

How to accurately define "close-in explosion" has always been a hotspot in the field of protection engineering research. In this paper, based on the fully validated 2D axisymmetric fine finite element model, the characteristics and laws of the propagation of air shock waves and high-speed expansion of detonation products generated by TNT spherical...

To explore the influence of thickness on the protective performance and damage mechanism of ultra-high molecular weight polyethylene (UHMWPE) laminates penetrated by 7.62 × 39 mm steel core bullets, field firing tests were carried out for 10-, 20-, and 30-mm-thick laminates at 10°C. The deformation and failure process, final failure state and defor...

According to the concept of performance‐based design, the fire safety design of the timber structures should be focused on the actual design fire, which represents the realistic fire situation in a given building. However, the current prescriptive only provides a method for evaluating the fire resistance of timber components under standard fire. Th...

Intermediate crack (IC) debonding is a common failure mode of externally bonded (EB) FRP-strengthened RC beams. This debonding failure initiates at an intermediate crack and propagates towards a plate end. New epoxy anchor was proposed recently by the authors and has shown its effectiveness in enhancing interfacial bonding behaviour and therefore i...

To investigate the dynamic responses and comprehending the damage mechanism of coral aggregate concrete (CAC) in compression, both the experimental and numerical investigations were implemented in the present work. Firstly, the dynamic mechanical properties of CAC at different strain rates were tested through the Split-Hopkinson pressure bar (SHPB)...

Dynamic tensile properties of concrete play a very important role in the blast-resistant performance of concrete structure. Systematic tests on the tensile properties of normal concrete at high strain rates in the direct-tension way by using an improved Split Hopkinson Tension Bar (SHTB) technique were carried out. Quasi–static direct-tension test...

Gas explosion accidents could lead to great losses of lives and property. Reliable prediction of structural responses under gas explosion loads is essential for developing effective technologies to mitigate the potential hazards of gas explosions. In the present study, numerical studies are conducted to investigate the performance of utility tunnel...

The paper presents a mesoscopic investigation into the effects of specimen size and strain rate upon the strength and failure modes of coral aggregate concrete (CAC) in splitting tension. The 3D mesoscale modelling approach that assumes CAC as a tri-phase composite (i.e., aggregate, mortar and ITZ) was established to simulate its tensile behaviours...

12 batches of premixed methane-air mixture explosion tests were conducted in a 30 m long testing tube with section dimensions of 0.8 m × 0.8 m to explore the loading characteristics of gas explosion inside the tube. The pressure-time histories and flame travel distance of each test were recorded and analyzed. A 3D numerical model was developed and...

Depleted uranium (DU) has surprising physical properties such as a high density, high hardness, and high toughness. A numerical method was developed in AUTODYN to study the penetration performance of a shaped charge with a liner made of DU with 0.75% titanium. By comparing different parameters and results from different models, the strength model s...

To efficiently improve the anti-blast performance of current reinforced concrete (RC) structures, three different retrofitting methods using the carbon fiber reinforced polymer (CFRP) sheets were proposed. Field tests were carried out on the FRP retrofitted columns subjected to close-in and double-end-initiation explosions. The recorded dynamic dam...

Dynamic failures (e.g., crater, crack and spall) can be observed in concrete structures when suffered from possible blast and impact loadings. Understanding the physical mechanisms behind these failures needs a sound material model that thoroughly considers the damage mechanisms of concrete material, especially under the high confinement situation...

The dry coral sand specimens confined by a steel sleeve were tested by the spilt Hopkinson pressure bar (SHPB) system with a striker-impact velocity of 10 m/s. The effect of relative density on the mechanical behaviour of dry coral sand was investigated. Specimens of three relative densities, namely, 10%, 50%, and 90%, which were corresponding to m...

Design values of overpressure have been reported for spherical charges detonated at the center of the sphere. This paper focuses on the influence of detonation point on the distributions of incident overpressure and impulse of cylindrical charges. A numerical model was developed by using AUTODYN-2D. Numerical analyses were performed by calculating...

The dynamic tensile properties of coral aggregate seawater concrete (CASC) play a substantial role in reef engineering and marine military defense engineering applications. CASC and sisal fiber coral aggregate seawater concrete (SFCASC) with sisal fiber content of 3 kg/m³ were prepared in this study. The dynamic tensile test under high strain rate...

Rapid increase of urban underground constructions has a great consideration of underground environment safety and how to expel toxic gases out of tunnels effectively. The utility tunnel is a typical urban tunnel construction with multiple underground pipelines including gas pipelines, and is necessary to investigate characteristic of gas diffusion...

Liquefied natural gas (LNG) leaks often lead to cascading accident disasters, including vapor cloud release, explosion, fire, and toxic gas release. The origin and evolution of each accidental disaster must be considered when assessing safety. This paper discusses the safety assessment project of an LNG gas storage station in Xuzhou, China. Multipl...

The dynamic compressive behavior of concrete is closely associated with the specimen size effect and the coupling effect of strain rate and specimen size on the compressive properties is something there worthy studying for the development and application of coral aggregate concrete (CAC). A novel 3D mesoscale modelling approach taking the random ch...

This study carried out an experimental investigation on the effectiveness of newly proposed epoxy anchors on the interfacial bond performance between basalt fibre reinforced polymer (BFRP) sheets and concrete. The parameters examined included the size of epoxy anchors and the number and spacing of anchors. It is concluded that the proposed epoxy an...

Basalt fiber-reinforced polymer (BFRP) has been applied for strengthening concrete structures. However, studies on reinforced concrete (RC) slabs strengthened by BFRP strips under impact loads are limited in open literature. This study investigates the efficiency of using BFRP strips with various strengthening layouts and anchoring schemes on the i...

Reinforced concrete (RC) structures consume large amounts of energy supply and cause continuing pollution. During the life cycle of RC structures, operating and embodied energy are significant contributors to the whole energy demand. The embodied energy is smaller than the operating energy but its proportion in the total life-cycle energy is increa...

Typical failures such as cratering, cracking and spalling are frequently observed on the frontal and distal surfaces of concrete slabs when subjected to impact loadings. A high-fidelity physical-based numerical simulation should not only predict the ballistic parameters, but these failures, where an accurate material model and an appropriate algori...

This paper focuses on the mechanical response of double-layer aluminum foam under static and impact loading. In the first part, experimental investigations are conducted to research the static and dynamic response of aluminum foam. The mechanical response of single- and double-layer specimens is discussed. In the second part, a mesoscopic model is...

Five Reinforced Concrete (RC) beams strengthened with Basalt Fiber Reinforced Polymer (BFRP) grid in conjunction with Engineered Cementitious Composite (ECC) were tested along with one conventional RC beam for reference to investigate their performance improvement, particularly in shear capacity, due to strengthening. The test results highlighted t...

This Special Issue aims to present the state-of-the-art research and understandings on the analysis and design of protective structures against blast and impact loading. Both original research articles, as well as review articles discussing the current state of the art, are welcomed. Potential topics include but are not limited to the following: St...

The bending behavior of reinforced concrete beams under uniform pressure is critical for the research of the blast-resistance performance of structural components under explosive loads. In this study, a bending test of five reinforced concrete beams with the dimensions of 200 mm (width) × 200 mm (depth) × 2500 mm (length) under uniform load produce...

A novel pultruded carbon fiber–reinforced polymer connection technique for civil engineering that is called pre-tightened single tooth joint has been proven to have good static properties. To investigate the fatigue behavior of the joint, a series of laboratory experiments were carried out. The effects of load level and transverse clamping force on...

This experimental investigation examines the influence of coarse aggregate size (i.e. 5–10 mm, 10–15 mm, and 15–20 mm) on the dynamic interfacial bond behaviour between BFRP and concrete under various loading speeds (i.e. 8.33E−6, 0.1, 1.0, 3.0, 5.0, and 8.0 m/s). The testing results including the interfacial bond strength and bond-slip responses a...

Based on the mix proportion design principle of high performance lightweight aggregate concrete, rich slurry concrete theory and fiber reinforced toughening technology, high strength Coral Aggregate Seawater Concrete (CASC) and sisal fiber reinforced CASC (SFCASC) with 28d cube compressive strength of 74.6 MPa and 77.3 MPa respectively were prepare...

This article was withdrawn on 4 September 2019 at the request of the authors. This paper is focused on the dynamic properties of concrete slab under blast. Firstly, a numerical model of reinforced concrete slab covered with aluminium foam is set up. The hydrocode, LS-DYNA, is employed in simulation. Secondly, numerical simulations are carried out t...

Explosion risk of the container yard stored with dangerous goods has drawn much attention in the society, since the”8.12”explosion accident in Tianjin Port. Due to the randomness of transportation and storage，it’s very difficult to determine the explosion power of dangerous goods stacked in the container yard, which, however, is required urgently b...

Under the action of earthquakes,some key components of underground structures may be damaged,and the stability of the whole structure may deteriorate.Based on the traditional response displacement method,a new response analysis method of displacement time-history is proposed,and the characteristics and solution procedure of the method are introduce...

The axial load-carrying column is commonly considered as the most critical component in RC structure. To determine the failure characteristics of the RC column under the combined action of axial load and close-in explosion initiated at two ends of an explosive cylinder, large-scale blast tests were carried out, with consideration to different charg...

The Pressure–Impulse (P-I) diagram is generally accepted as a useful tool that permits easy assessment of structural responses to a specified load. To predict the failure characteristics of typical reinforced concrete (RC) columns subjected to blast loads, P-I diagrams considering different failure modes were generated with a high efficient procedu...