Liner Thickness Research Articles

Short-term outcomes of thin highly cross-linked polyethylene liners in primary total hip arthroplasty.

The use of thin highly cross-linked polyethylene (HXLPE) liners in total hip arthroplasty (THA) allows utilisation of larger femoral heads. However, concern surrounding postoperative complications remains. This study aims to investigate rates of revision and re-admission associated with thin HXLPE liners at short-term follow-up. We retrospectively reviewed 3047 patients who underwent THA with a cementless modular acetabular implant with a 36-mm femoral head, and different thicknesses of HXPLE liners from 2011 to 2021. We identified 723 patients (23.7%) with a minimum 2-year follow-up and 206 patients (6.8%) with a minimum 5-year follow-up. Patients in the thin group (TG, n = 1020) received <5.1-mm liners with 52-mm size cups while patients in the non-thin group (NTG, n = 2027) received >5.1-mm liners with >52-mm size cups. Outcomes were compared using multi-variable logistic regressions while controlling for all significant demographic differences. We found no significant differences in re-admission (3.9% vs. 4.3%, OR 0.97; 95% CI, 0.63-1.49; p = 0.874) and revision (2.5% vs. 3.2%, OR 0.72; 95% CI, 0.41-1.26; p = 0.246) rates between groups. The difference in fracture rate between groups was not significant, but the 1 recorded acetabular fracture (5%) occurred in the NTG. Although the rate of liner exchange was lower in the TG (1.1%) compared to the NTG (2.3%), the difference was not statistically significant (OR 0.51; 95% CI, 0.24-1.05; p = 0.068). Liners were exchanged for liner wear in 1 hip (1%), aseptic reasons in 38 hips (66%), and peri-prosthetic joint infection in 19 hips (33%). Patients undergoing THA with a thin liner were not significantly predisposed to higher rates of revision surgery or poorer clinical outcomes at short-term follow-up when compared to those who received a thicker liner. Consequently, further long-term studies regarding the utility of thin HXLPE implants in reducing complications should be pursued.

Contact stress and sliding wear damage tolerance of hydroxyapatite and carbon nanotube reinforced polyethylene cup liner against zirconia femoral head

A finite element modeling (FEM) approach is carried out to estimate the contact stresses such as von-Mises and shear stress on the acetabular cup liner, made up of ultra-high molecular weight polyethylene (UHMWPE)-hydroxyapatite (HAp)-carbon nanotubes (CNT) based composites. The highlights of this work include the effects of liners' material (UHMWPE-HAp-CNT composites), radial clearance (0.05 to 1 mm), and liners' wall thickness (3 to 8 mm) on contact stresses. The thick liner (thickness: 8 mm) with conformal geometry (radial clearance 0.05 mm) produced the lowest contact stresses (von-Mises: 13.8–17.5 MPa and shear stress: 2.3–3.3 MPa). In contrast, the thin liner (thickness: 3 mm) with higher radial clearance (1 mm) showed the highest von-Mises stress (78.6–131.0 MPa) and shear stress (17.0–23.3 MPa). According to ISO 7206–1, nearly 6–7 times reduced contact stresses were observed because of the wider articulating contact area provided by thick cup liner and its conformity with respect to the femoral head. The UHMWPE-2 wt % CNT composite (UC) showed low von-Mises stress (16.1 MPa) and lowest shear stress (2.3 MPa); thus, it is the most damage tolerant material (wear rate: 2.6 × 10-7 mm3/Nm). The excellent mechanical properties such as hardness (165 MPa), elastic modulus (2.28 GPa), and tensile strength (36.7 MPa) are reasoned to elicit an increased sliding-wear resistance of UC. Thus, CNT-based UHMWPE composite can be the potential acetabular cup liner with a thickness of 8 mm and clearance of 0.05 mm without plastic deformation.

Study on optimization of jet forming of tandem shaped charge warhead

In order to greatly improve the length of shaped charge jet and optimize the jet forming performance, the forming process of a tandem shaped charge structure with reverse detonation mode was numerically simulated. The effects of the rear and front stage liner thickness on the jet length, jet head velocity, jet kinetic energy and energy conversion rate were analyzed respectively using LS-DYNA finite element analysis software. Then the optimal thickness of the front and rear stage liner of the tandem shaped charge structure was optimized, and the jet length was measured. Under the condition of charge diameter of 200 mm, when the liner thickness was 0.02CD (charge diameter) for K-charge and liner thickness was 0.25CD for the front stage warhead, the jet forming was stable and the length is the longest. After the two-stage warhead was detonated in reverse order (the initiation delay time was 220 μs), a tandem jet can be formed, and the effective jet length (excluding the pestle body) is 65 % higher than that of the later stage charge.

Design of the composite hydraulic cylinder with geodesic dome trajectory: A numerical study

AbstractHydraulic cylinders are used in many different areas from aviation to construction machinery and are generally manufactured using conventional steels that stand out with their low strength to weight ratio. In this study, it was aimed to design a hydraulic cylinder using composite materials to reduce cylinder weight. In this context, a novel composite hydraulic cylinder was designed, and numerical analyses for the composite portions of the hydraulic cylinder were carried out. For the numerical model, an aluminium liner and cylinder heads with the geodesic dome profiles were used, and composite layers were formed on their surfaces by using the Ansys ACP module. In the numerical analyses, the design parameters such as fabric materials and liner thickness were optimized using response surface optimization, and thus the optimum design parameters were determined. The results were verified by comparing the statistical‐based optimization and numerical analysis results. On the other hand, the wall thickness for the steel hydraulic cylinder, which has the same strength as the composite cylinder, was determined and the structure weights have been compared. As a result of the current study, it has been revealed that composite hydraulic cylinders with the same strength as steel hydraulic cylinders can be designed. With the utilization of the composite materials, it has been observed that composite hydraulic cylinder is 53.78% lighter than conventional hydraulic cylinders. Furthermore, the advantages and disadvantages of the novel composite hydraulic cylinder were discussed, and it was found to be feasible for industrial applications in which system weights are the major problem.

Theoretical investigation on the upheaval thermal buckling of a lined subsea pipeline

In this study, according to the nonlinear von-Kármán assumption and Euler-Bernoulli beam theory, a mathematical model is proposed to simulate upheaval buckling of lined subsea pipelines, which considers the difference in material properties of the liner and outer pipe. A closed-form solution is derived. The analytical solutions are verified by comparing them with the results in the literature. The influence of Young's modulus and the thermal expansion coefficient of the liner on the post-buckling response is analysed. The post-buckling behaviour of the outer pipe and liner are compared. The effect of the ratio of the liner's thickness to the outer pipe's thickness on the post-buckling response of the lined subsea pipeline is analysed in detail. The results show that the liner must be included in the analysis of upheaval thermal buckling. The post-buckling behaviour of both the liner and outer pipe are affected significantly by the thermal expansion coefficient of the liner. The displacement amplitude, axial compressive force, maximum bending moment and maximum stress all increase with increasing ratio of the liner's thickness to the outer pipe's thickness.

Investigation of the Effect of Child Helmet Design Parameters on Head and Brain Injuries Using Reduced-Order Modelling

A helmet is the main protective equipment for a child pillion passenger. A safe helmet must be able to mitigate head and brain injuries resulting from high head impact loading. A lightweight helmet is preferable, especially for children. This paper proposed to study the effect of materials, liner thickness, and friction at the head–helmet interface on linear and rotational accelerations using reduced-order modelling. A child head–helmet finite element model was developed and validated against an experiment. Finite element simulations were conducted to generate training data for the establishment of reduced-order models which were subsequently used to predict the linear and rotational accelerations for various helmet parameters. The prediction could be performed in a very short time compared to its corresponding finite element simulation. The use of aluminium foam enhanced mitigation of the linear and rotational accelerations as well as weight reduction. This study also revealed that the head–helmet friction coefficient had a strong effect on the rotational acceleration, while the liner thickness predominantly affected the linear acceleration. However, the liner thickness had less influence on the rotational acceleration when the head–helmet friction was low. The risk of brain concussion as well as diffusional injury could be reduced by enabling low friction at head–helmet surface.

Numerical Investigation of Hot Roll Bonding of Multilayer Sheet Metal

The roll bonding process of the sandwich sheet is a preferable production method to manufacture multilayer sheets and it needs clear investigation because some industrial parts cannot fulfill all of the requirements by single-layer material. In this study, a theoretical model of roll bonding has been reviewed and hot sandwich rolling processes with different plate thickness and flow stress were numerically investigated. The contact pressure-dependent bonding properties in the deformation zone were defined. Then, the liner thickness and reduction ratio are important parameters to determine the total deformation zone. When the thickness of the liner becomes large, unbonded length of deformation can be a serious problem and at the same time, the good bonding strength can be found at a higher reduction ratio of the thinner liner.

Green's functions based on the Timoshenko beam model for the longitudinal seismic dynamic response of tunnels crossing soft and hard rock strata

Weathered rocks typically exist in the portal section of mountain tunnels where the tunnels in the portal section often cross soft and hard rock strata. The interface between the soft and hard rocks is the control point in the seismic design of tunnels. However, there is currently no seismic design method based on dynamic methods that consider tunnels crossing soft and hard rock strata along their longitudinal direction. In this study, two elastic foundation beams in different rock strata were used to model the behaviour of a tunnel crossing soft and hard rock strata. Based on the Timoshenko beam vibration response theory, the higher-order differentials of the beam dynamic governing equation are transformed into algebraic equations using the Laplace transform. The closed-form solution of the dynamic response of the entire beam is derived by combining the boundary and deformation coordination conditions of two elastic foundation beams. Subsequently, the dynamic response of any point along the longitudinal direction of the elastic foundation beam (tunnel) crossing the soft and hard rock strata was obtained using Green's function. The validity of the method was verified by comparing it with a finite difference model. Finally, a parametric analysis was performed based on the analytical method derived in this study to investigate the influences of parameters such as the liner elastic modulus, liner thickness, modulus of elasticity ratio of hard rock to soft rock, and axial forces, on the seismic response of tunnels crossing soft and hard rock strata. The results suggest that with an increase in lining thickness, the bending moment and shear force of the tunnel become increasingly significant, but the transverse displacement response of the tunnel was slightly affected. With an increase in the elastic modulus of the lining, the difference in the peak values of the bending moment and shear force increases, whereas the transverse displacement response is slightly diminished. With an increase in the elastic modulus ratio of hard rock to soft rock, the difference in the peak values of the bending moment, shear force, and transverse displacement of the tunnel, varied more along the tunnel axis. With the increase in the axial force, the seismic responses from the bending moment and shear force on the tunnel cross-section were significantly weakened.

Influence of different shaped charge parameters on jet penetration into metallic target

In this paper, Autodyn-2D hydrocode is used to investigate the influence of shaped charge parameters on penetration performance. Two different algorithms of Autodyn-2D hydrocode are used to predict the jet penetration depthsinto steel target; they are: i)jetting analyses algorithm, and ii) jet formation and penetration algorithm. To validate the predictions of the present work, Autodyn hydrocode is fed with the data of tested shaped charges with different liner thicknesses. The predicted penetration depths are compared with the corresponding experimental measurements; good agreement is generally obtained. Then, the shaped charge with liner thickness of 1.1mm, that gives the maximum jet penetration into steel target, is selected to study the influence of other different shaped charge parameters on its penetration performance. These parameters include form, material and thickness of liner, standoff distance and type of high explosive material. The influence of each studied parameter is evaluated by comparing the jet penetration performance with that of the selected shaped charge. Samples of the obtained predicted results showing the influence of each shaped charge parameter on jet formation and its penetration depth into steel target are presented and discussed. Four configurations are simulated into Autodyn-2D hydrocode considering the parameters that improve the penetration performance of the selected shaped charge. The obtained predictions result in the replacement of RDX by HMX explosive type and increasing the standoff distance from 29 to 40mm of the selected shaped charge will improve its penetration capability by 28.5%.

Minimum Five-Year Outcomes of Modular Dual Mobility in Primary Total Hip Arthroplasty

Using a modular dual-mobility (MDM) bearing in primary total hip arthroplasty (THA) has not been widely evaluated. The purpose of this study is to evaluate clinical outcomes and survivorship following MDM bearings in primary THA. We used our registry database for patients with an MDM bearing on primary THA, performed by 6 surgeons through supine direct lateral or direct anterior approach. MDM bearings were used most often when impingement or subluxation was present intraoperatively despite proper component position. Another indication was a patient with planned activities who might be at a higher risk of instability postoperatively. A total of 127 MDM bearings were used in primary THA in 119 patients. Mean follow-up was 6.77 years (range 5-8.9). Five hips were revised, none of which were due to MDM bearing failure. Preoperative Hip dysfunction and Osteoarthritis Outcome Score for Joint Replacement, Veterans RAND/Short Form 12 Physical Health Score and Mental Health Score increased from 25.81 to 52.40 (P < .0001), 30.42 to 44.50 (P < .0001), and 36.21 to 52.70 (P < .0001) at latest completed survey follow-up, respectively. This MDM bearing shows excellent functional outcomes at a minimum 5 years of follow-up with no bearing-related failures. It can be an excellent choice in primary THA specifically in females where the use of increased head size to prevent instability is not possible due to anatomical restrictions and liner thickness.

Formation characteristics and penetration performance of an underwater shaped charge jet

This study aims to investigate the formation characteristics and penetration performance of an underwater conical shaped charge jet. First, a new theoretical model for underwater jet formation is proposed by the virtual mass method. Based on the theoretical model and the ALE algorithm, the influences of standoff height, cone angle, liner thickness and initiation manner on the jet formation characteristics and penetration ability are analyzed. Then the experiments of underwater shaped charge jet are carried out to verify the theoretical and simulation results. Finally some instructive conclusions are drawn: (i) the theoretical model based on the virtual mass method can accurately predict the initial jet parameters and calculate the penetration depth, and the error between the theoretical and experimental results is less than 8%. (ii) The penetration depth initially increases and then decreases with increasing standoff height. The optimal standoff height is approximately 4–4.5 times the charge diameter. (iii) at the optimal standoff height, the penetration depth decreases with the increase of the cone angle, and the optimal cone angle is 40°–50°. (iv) The penetration depth decreases with increasing the liner thickness, and the jet shape and penetration depth formed by the ring initiation manner are better.

Scheme Design of Xenon Composite Over-wrapped Pressure Vessel for Electric Propulsion System

The composite over-wrapped pressure vessel (COPV), which were made by ultra-thin metal liner and high strength carbon fiber reinforced plastic (CFRP), has high performance factor (PV/W). COPV were widely used in electric propulsion system (EPS) of space system. ANSI/AIAA S-081-2000 is a general standard for pressure vessel of aerospace field at home and abroad, it specified the design elements, references, specifications, requirements in detail. The materials selection of liner, CFRP and skirt are introduced respectively. The design contents of liner and CFRP are explained. The liner is designed in terms of equal strength principle and the composite structure was designed in term of hoop fiber layers and spiral fiber layers alternately over-wrapped. The skirt is composite structure, with X-X carbon fiber over-wrapped the TC4 titanium alloy. The titanium liner thickness is 0.8mm, Cycle life is at last 100 times when the liner thick is ultra-thin. The safe life was designed, including stress-rupture life and low cycle fatigue-life. The leak before burst (LBB)safe failure mode was analyzed. The results show that the structure design meets the technical requirements.

Mechanisms of Scaling Effect for Emerging Nanoscale Interconnect Materials.

The resistivity of Cu interconnects increases rapidly with continuously scaling down due to scatterings, causing a major challenge for future nodes in M0 and M1 layers. Here, A Boltzmann-transport-equation-based Monte Carlo simulator, including all the major scattering mechanisms of interconnects, is developed for the evaluation of electron transport behaviors. Good agreements between our simulation and the experimental results are achieved for Cu, Ru, Co, and W, from bulk down to 10 nm interconnects. The line resistance values of the four materials with the inclusion of liner and barrier thicknesses are calculated in the same footprint for a fair comparison. The impact of high aspect ratio on resistivity is analyzed for promising buried power rail materials, such as Ru and W. Our results show that grain boundary scattering plays the most important role in nano-scale interconnects, followed by surface roughness and plasma excimer scattering. Surface roughness scattering is the origin of the resistivity decrease for high-aspect-ratio conductive rails. In addition, the grain sizes for the technical nodes of different materials are extracted and the impact of grain size on resistivity is analyzed.

To what extent could the acetabular liner thickness be reduced yet remaining tribologically acceptable in metal‐on‐vitamin E‐diffused crosslinked polyethylene hip arthroplasty?

The aim of the present study was to evaluate how much reduction in acetabular liner thickness could be tribologically acceptable in metal-on-vitamin-E diffused highly crosslinked ultra-high molecular weight polyethylene (Vit-E XLPE) bearings for total hip arthroplasty. We tested thick- (10.3 mm), moderate- (6.3 mm), and thin- (4.3 mm) Vit-E XLPE liners coupled with 28-mm cobalt-chromium femoral heads on a hip simulator to 5 million cycles, and peak contact stress was predicted based on mathematical modeling. Wear damage was also evaluated in terms of surface topology and morphology. Wear simulation demonstrated that the 2-4 mm thickness reduction (6.3 → 4.3 mm and 10.3 → 6.3 mm) did not significantly affect the wear rate for Vit-E XLPE liner, whereas 6-mm reduction (10.3 → 4.3 mm) significantly increased liner wear (by 309%) and head roughness (by 415%). This effect was attributed to a contact stress increase (by 24-41%). However, the wear rates for all thicknesses tested were much lower than those previously reported for thicker non-crosslinked materials. The original crystalline morphology was maintained in all liners after wear. Our results suggest that the 2-4 mm thickness reduction may be tribologically acceptable in Vit-E XLPE liners. However, more severe and longer term simulations are necessary to determine a minimum acceptable thickness.

Development of Test Cycle for Centrifugal Clutch of CVT Driven Scooters Intended for Urban Traffic Conditions

The present study deals with the development of a test cycle for the centrifugal clutch of continuously variable transmission (CVT) driven scooters. Centrifugal clutch experiences different duty cycles during the usage of scooters in city traffic and highways during its lifetime. Since the friction characteristics of the centrifugal clutch are controlled by acquired factors, it is difficult to predict ideal friction characteristics under all conditions. The wear of friction lining increases due to heat generated in the clutch assembly because of the repeated “stick-slip” phenomena. Therefore, an attempt has been made for developing à new test cycle by keeping the engagement frequency as a reference. Road load data for three different riding conditions have been collected and analyzed. The developed test cycle has been automated on the centrifugal clutch test bench and a new set of clutch liners was tested thoroughly. The surface roughness, thickness, and wear of clutch liners have been observed and evaluated against the field vehicles. For the surface roughness, maximum deviations of 3.74%, 3.36%, and 2.16% have been observed for trailing, middle and leading sections of clutch liners respectively. For the thickness, maximum deviations of 3.06%, 2.59%, and 3.14% have been observed for trailing, middle and leading sections of clutch liners respectively. The developed test cycle demonstrates a good correlation with field use.

Numerical simulations of the formation behavior of explosively formed projectiles

Explosively formed projectile (EFP) is a self-forging shape charged structure having very high penetration ability compared to conventional kinetic energy projectile. The penetration capability of an EFP is strongly dependent on various design parameters. The main parameters can be roughly divided into geometric and material parameters used in the warhead configuration.&#x0D; The present research is an effort to study the effect of metal casing thickness, type of metal used for casing, explosive type, liner thickness, type and configuration on the formation of EFP. Effectivness of an EFP is studied in terms of final velocity and shape of formed penetrator. The study is carried out by performing a number of simulations by using explicit finite element (FE) hydrocode ANSYS/Autodyn.

АНАЛИЗ ВЛИЯНИЯ НАСТРОЕЧНЫХ ПАРАМЕТРОВ ПРОШИВНОГО СТАНА НА ИЗМЕНЕНИЕ ДИАМЕТРА И ТОЛЩИНЫ СТЕНКИ ГИЛЬЗЫ

In the production of seamless pipes, a mass method is the use of billet piercing at helical rolling mills with the first rolling at longitudinal rolling mills. At the same time, increased requirements are imposed on the quality and geometric parameters of finished pipes. Geometric parameters include such as wall thickness, diameter, thickness variation. In this case, the difference in thickness mainly affects the quality of the liner. It is known that the same geometric parameters of the sleeve (diameter and wall thickness) can be obtained at different distances between the rolls, the distance between the holding tool, the extension of the mandrel beyond the clamping. However, in this case, the difference in thickness of the liners will be different. In addition to the tuning parameters, the degree of tool wear, in particular, the mandrel of the piercing mill, also affects the thickness difference. It was found that as the mandrel of the piercing mill wears out, the diameter of the liner monotonically increases, which leads to a redistribution of the liner wall, and, accordingly, the difference in liner thickness. This work is devoted to the search for rational tuning parameters in order to minimize the thickness difference. An experimental plan was developed using modeling in the QForm environment. The obtained sleeves were processed according to the geometric parameters. Based on the data, the mean square error coefficient (RSME) was calculated for various models of regression equations. For the selected model, nomograms of the distribution of thickness variation, wall thickness, and sleeve diameter were constructed depending on the tuning parameters. These nomograms can be used in industrial practice for the operational calculation of geometric parameters when the conditions for piercing workpieces change. As a project, recommendations were developed for obtaining liners with a wall thickness of 17 mm with a minimum thickness difference.

An Analytical Model for Almost Conformal Spherical Contact Problems: Application to Total Hip Arthroplasty with UHMWPE Liner

Due to its high relevance for designing ball joints in mechanical engineering and (artificial) hip joints in biomechanics, the almost conformal elastic contact between a sphere and a spherical cup represents an important contact problem of current research. As no closed-form analytical solution to the problem has been found to date, full computational methods such as the finite element method are needed for analysis. However, they often require incredibly long, unacceptable calculation times, making parameter studies hardly practicable. For this reason, approximate analytical and semi-analytical models are applied, capable of predicting quantities of interest with sufficient accuracy. In the present work, a very simple model based on a radially directed Winkler foundation is presented, which provides (approximate) closed-form analytical solutions for both the pressure distribution and the dependencies between macroscopic contact quantities such as normal force and indentation depth. To ensure an optimal mapping of a specific contact problem, only the foundation modulus must be defined in a suitable way. As an example, the proposed model has been successfully adapted to adequately simulate the frictionless normal contact for hard-on-soft hip implants. For this purpose, the foundation modulus was approximated with the aid of a finite element analysis instead of adopting it from already well-established models, as the latter produce clearly erroneous results for large liner thicknesses and large Poisson’s ratios. By a comparison with extensive parameter studies of finite element simulations, it is demonstrated that the proposed model provides acceptable results for all commonly used hard-on-soft hip implants. On this basis, the influence of geometrical changes of the femoral head and the acetabular cup on the maximum pressure as well as the half-contact angle is discussed, and consequences on the wear behavior are deduced.

Buckling analysis of thin-walled metal liner of cylindrical composite overwrapped pressure vessels with depressions after autofrettage processing

Abstract The cylindrical filament wound composite overwrapped pressure vessels (COPV) with metal liner has been widely used in spaceflight due to their high strength and low weight. After the autofrettage process, the plastic deformation of the metal liner is constrained by composite winding layers, which introduce depressions to the metal liner that causes local buckling. To predict the local buckling of the inner liner with depressions of the pressure vessel after the autofrettage process, a local buckling analysis method for the metal liner of COPV was developed in this article. The finite element method is used to calculate the overall stress distribution in the pressure vessel before and after the autofrettage process, and the influence of local depressions on the buckling is evaluated. The axial buckling of the pressure vessel under external pressure is analyzed. The control equation of the metal liner with depressions is developed, considering the changes in the pressure and the bending moment of the liner depressions and its vicinity during the loading and unloading process. Taking the cylindrical COPV (38 L) with aluminum alloy liner as an example, the effects of liner thickness, liner radius, the thickness-to-diameter ratio, autofrettage pressure, and the length of straight section on the autofrettage process are discussed. The results show that the thickness of the inner liner has the most significant influence on the buckling of the liner, followed by the length of the straight section and the radius of the inner liner, while the autofrettage pressure has the least influence.

Effect of TiN Liner Thickness on the Electrical Characteristics and Reliability of CuGeS2/GeS2-Based Selector Device

Three-dimensional (3D) cross-point memory technology has attracted much attention for the future ultrahigh-density memory applications [1]. However, when the resistor (1R) without the selector device is applied to the 3D crosspoint memory cell, the power consumption is extrememly high due to the leakage current, which is a major obstacle in large-scale memory operation. To supress the leakage current, it has been proposed that a selector (1S) is stacked vertically with a resistor (1R). The selector device should have ultralow leakage current and high selectivity to avoid any undesired operation of the unselected memory cells. Among the various selector devices, mixed-ionic-electronic-conduction (MIEC) type selector has been intensively researched as it showed abrupt resisitive switching through the formation and rupture of the metal filaments, resulting in high selectivity (~ 104) and low leakage current (~ 10 pA) [2]. However, the selector device using metal filaments suffer from reliability issues such as endurance failure due to the accumulation of excessive amounts of metal ions in the switching layer [3]. Therefore, it is important to find an efficient solution that improves selectivity and endurance characteristics by controlling the diffusion of excessive amounts of metal ions.In this work, we demonstrated the selector device adopting TiN liner as a diffusion barrier to control the diffusion of Cu into the switching layer. The effects of the TiN liner thickness on the reliability and electrical chacateristics (i.e. Vth, Vh, selectivity) of the GeS2-based selector device were investigated in detail. The schematic image of a selector device without a TiN liner, with a 1-nm-thick TiN liner, and with a 2-nm-thick TiN liner were demonstrated, as shown in Fig. 1(a-c). The GeS2 based selector device has a structure of the plug-type bottom W electrode, 5-nm-thick GeS2 switching layer, 0 to 2 nm-thick TiN liner, 5-nm-thick CuGeS2 ion supply layer, and 50-nm-thick Pt top electrode. A typical DC I-V curve of GeS2 based selector device without a TiN liner exhibited a threshold voltage (V th) of ~ 0.60 V, a holding voltage (V h) of ~ 0.00 V, and a selectivity of ~ 4.59 × 105, as shown in Fig. 1(d). Moreover, a typical DC I-V curve of GeS2 based selector device with a 1-nm-thick TiN liner exhibited a threshold voltage (V th) of ~ 0.75 V, a holding voltage (V h) of ~ 0.15 V, and a selectivity of ~ 1.14 × 106, as shown in Fig. 1(e). Lastly, a typical DC I-V curve of GeS2 based selector device with a 2-nm-thick TiN liner exhibited a threshold voltage (V th) of ~ 1.00 V, a holding voltage (V h) of ~ 0.25 V, and a selectivity of ~ 3.10 × 106, as shown in Fig. 1(f). These results indicated that the threshold voltage (V th), the holding voltage (V h), and the selectivity increased as the thickness of the TiN liner increased. Afterwards, the dependence of the endurance characteristics according to the thickness of the TiN liner of the selector device was evaluated. GeS2 based selector device without a TiN liner demonstrated endurance cycles of ~ 5 × 105, as shown in Fig. 1 (g). Moreover, the endurance characteristic of GeS2 based selector device with 1-nm-thick TiN liner demonstrated endurance cycles of ~ 5 × 106, as shown in Fig. 1 (h). Lastly, the endurance characteristic of GeS2 based selector device with 2-nm-thick TiN liner demonstrated endurance cycles of ~ 1 × 106, as shown in Fig. 1 (i). This result suggested that the optimal liner thickness for the diffusion of an adequate amount of Cu is important to achieve electrically reliable switching characteristics. In the presentation, the effects of TiN liner thickness on Cu diffusion will be assessed in detail using transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) elemental mapping, and line profile. Reference [1] Geoffrey W. Burr. et al. J. Vac. Sci. Technol. B 32, 040802 (2014)[2] K. Virwani et al., IEDM Tech. Dig. 2012, 2.7.[3] Song, J. et al. IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 64, NO. 11, 2017 Acknowledgement This research was supported by the MOTIE (Ministry of Trade, Industry & Energy (10068055) and KSRC (Korea Semiconductor Research Consortium) support program for the development of the future semiconductor device. Figure 1