End Of Segment Research Articles

Influence of Contact Interface Friction on Plastic Deformation of Stretch-Bend Forming

The contact interface friction between the specimen and the mold during the stretch-bend is a complex interactive process. Friction causes the uneven distribution of tensile stress on the specimen, which affects the plastic flow of the forming material and the spring-back after forming. In this paper, the analytical model of frictional shear stress and tensile stress distribution in the contact mold segment of the stretch and bend synchronous loading stage was established. The influence law of friction coefficient and contact mold angle on the stress–strain distribution of the specimen contact mold segment was discussed. The effect of key factors affecting the friction state of the contact interface (mold surface roughness and contact mold angle) on the shrinkage deformation of the cross-section and the tensile deformation gradient of the specimen was analyzed by equivalent stretch-bend forming experiments. The results showed that the smaller the surface roughness of the mold was, the better the friction state of the contact interface was, the plastic deformation of the specimen was more uniform, and the difference between the section shrinkage and elongation of the contact mold segment and the suspension segment was smaller. Reducing the contact mold angle of the stretch-bend can bring down the tensile stress difference at both ends of the contact mold segment of the specimen so that the section shrinkage and tensile elongation of the contact mold segment and the suspension segment tend to be consistent.

Experimental study of non-Darcy flow characteristics in permeable stones

Abstract. This study provides experimental evidence of Forchheimer flow and the transition between different flow regimes from the perspective of the pore size of permeable stone. We first carry out seepage experiments on four kinds of permeable stones with mesh sizes of 24, 46, 60 and 80, corresponding to mean particle sizes (50 % by weight) of 0.71, 0.36, 0.25 and 0.18 mm, respectively. The seepage experiments show that an obvious deviation from Darcy flow regime is visible. In addition, the critical specific discharge corresponding to the transition between flow regimes (from pre-Darcy to post-Darcy) increases with increasing particle size. When the “pseudo” hydraulic conductivity (K, which is computed as the ratio of the specific discharge q and the hydraulic gradient) increases with increasing q, the flow regime is denoted pre-Darcy flow. After q increases to a certain value, the pseudo hydraulic conductivity begins to decrease; this regime is called post-Darcy flow. In addition, we use the mercury injection technique to measure the pore size distributions of four permeable stones with different particle sizes. The mercury injection curve is divided into three stages. The beginning and end segments of the mercury injection curve are very gentle, with relatively small slopes, while the intermediate mercury injection curve is steep, indicating that the pore size in permeable stones is relatively uniform. The porosity decreases as the mean particle sizes increases. The mean pore faithfully reflects the influences of the particle diameter, sorting degree and arrangement mode of the porous medium on seepage parameters. This study shows that the size of pores is an essential factor for determining the flow regime. In addition, the Forchheimer coefficients are discussed. The coefficient A (which is related to the linear term of the Forchheimer equation) is linearly related to 1/d2: A=0.00251/d2+0.003. The coefficient B (which is related to the quadratic term of the Forchheimer equation) is a quadratic function of 1/d: B=1.14×10-61/d2-1.26×10-61/d. The porosity (n) can be used to reveal the effects of the sorting degree and arrangement on the seepage coefficients. A larger porosity leads to smaller coefficients A and B for the same particle size.

The deuteron NMR Hahn echo decay in polyethylene oxide melts

The deuteron transverse relaxation properties of polyethylene oxide melts of four different molecular weights, covering the range from the onset of entanglements to the regime of fully entangled chains, are investigated using Hahn echo decays over an extensive time interval up to ten times the effective transverse spin relaxation time. The results are compared to predictions based on the Rouse and reptation formalisms, taking into account the dynamical heterogeneity of linear polymer chains produced by the end segments. The experimental results can be described qualitatively by a combination of both models, with the contribution of reptation dynamics increasing with growing chain length. The transition is continuous, rather than being characterized by sharp regime boundaries. Up to a molecular weight of 300.000 g/mol, the predicted limit of pure reptation dynamics is not yet reached. Quantitative deviations from the predicted decays as computed by numerical procedures become observable toward the long-time limit of the Hahn echo decays and are being discussed in terms of shortcomings of the available reptation theories.

Detailed behaviour of endothelial wall shear stress across coronary lesions from non-invasive imaging with coronary computed tomography angiography.

Evolving evidence suggests that endothelial wall shear stress (ESS) plays a crucial role in the rupture and progression of coronary plaques by triggering biological signalling pathways. We aimed to investigate the patterns of ESS across coronary lesions from non-invasive imaging with coronary computed tomography angiography (CCTA), and to define plaque-associated ESS values in patients with coronary artery disease (CAD). Symptomatic patients with CAD who underwent a clinically indicated CCTA scan were identified. Separate core laboratories performed blinded analysis of CCTA for anatomical and ESS features of coronary atherosclerosis. ESS was assessed using dedicated software, providing minimal and maximal ESS values for each 3 mm segment. Each coronary lesion was divided into upstream, start, minimal luminal area (MLA), end and downstream segments. Also, ESS ratios were calculated using the upstream segment as a reference. From 122 patients (mean age 64 ± 7 years, 57% men), a total of 237 lesions were analyzed. Minimal and maximal ESS values varied across the lesions with the highest values at the MLA segment [minimal ESS 3.97 Pa (IQR 1.93-8.92 Pa) and maximal ESS 5.64 Pa (IQR 3.13-11.21 Pa), respectively]. Furthermore, minimal and maximal ESS values were positively associated with stenosis severity (P < 0.001), percent atheroma volume (P < 0.001), and lesion length (P ≤ 0.023) at the MLA segment. Using ESS ratios, similar associations were observed for stenosis severity and lesion length. Detailed behaviour of ESS across coronary lesions can be derived from routine non-invasive CCTA imaging. This may further improve risk stratification.

Hybrid machine learning approach based intrusion detection in cloud: A metaheuristic assisted model

Cloud computing provides various cost-effective on-demand services to the user and so it is rising like a real trend in the IT service model. However, due to its open and distributed architecture, it is highly vulnerable to attackers. The security and privacy of cloud users has become a major hurdle. The most prevalent approach for detecting attacks on the cloud is the Intrusion Detection System (IDS). Scalability and autonomous self-adaptation weren’t features of contemporary IDS deployed in traditional Internet or Intranet contexts. Furthermore, they lack determinism, making them inappropriate for cloud-based settings. This necessitates the development of new cloud-based IDS capable of fulfilling the firm’s security standards. Therefore, in this research work, we have introduced a new IDS model for the cloud environment. Our research work is made up of four major phases: “data pre-processing, optimal clustering, feature selection, and attack detection phase”. Initially, the collected raw data are pre-processed to enhance the quality of the data. Then, these pre-processed data are segmented with the newly introduced K-means clustering model, where we’ve optimally selected the centroids by introducing a new hybrid optimization model referred as Spider Monkey Updated with Sealion Optimization (SMSLO), which is the conceptual hybridization of standard SeaLion Optimization (SLnO) and Spider Monkey Optimization (SMO), respectively. At the end of segmentation, two clusters (attack data and non-attack data) will be formed. The data available in both clusters seems to be huge in dimensions, so we’ve lessened the dimensions of the data in the clusters by applying the “Principal Component Analysis (PCA)” algorithm. Subsequently, these dimensionality-reduced features pass into the attack detection phase. The attack detection phase is modeled with the optimized Deep Belief Network (DBN), which portrays the type of attack (Dos, Botnet, DDoS as well) that intruded into the network. Since the DBN makes the final detections; it is ought to be less prone to errors. We have lessened the detection errors such as the Mean Square Error (MSE) of DBN by fine-tuning its weight using a new hybrid optimization model (SMSLO). Finally, the result acquired from the proposed work (DBN+SMSLO) is validated.

A comprehensive analysis of the intramural segment in interarterial anomalous coronary arteries using computed tomography angiography.

AimsAn anomalous coronary artery originating from the opposite sinus of Valsalva (ACAOS) with an interarterial course can be assessed using computed tomography angiography (CTA) for the presence of high-risk characteristics associated with sudden cardiac death. These features include a slit-like ostium, acute angle take-off, proximal luminal narrowing, and an intramural segment. To date, no robust CTA criteria exist to determine the presence of an intramural segment. We aimed to deduct new CTA parameters to distinguish an intramural course of interarterial ACAOS.Methods and resultsTwenty-five patients with an interarterial ACAOS (64% female, mean age 46 years, 88% right ACAOS) from two academic hospitals were evaluated. Inclusion criteria were the availability of a preoperative CTA scan (0.51 mm slice thickness) and peroperative confirmation of the intramural segment. Using multiplanar reconstruction of the CTA, the distance between the lumen of the aorta and the lumen of the ACAOS [defined as ‘interluminal space’ (ILS)] was assessed at 2 mm intervals along the intramural segment. Analysis showed a mean ILS of 0.69 ± 0.15 mm at 2 mm from the ostium. At the end of the intramural segment where the ACAOS becomes non-intramural, the mean ILS was significantly larger (1.27 ± 0.29 mm, P < 0.001). Interobserver agreement evaluation showed good reproducibility (intraclass correlation coefficient 0.77, P < 0.001). Receiver operator characteristic analysis demonstrated that at a cut-off ILS of <0.95 mm, an intramural segment can be diagnosed with 100% sensitivity and 84% specificity.ConclusionThe ILS is introduced as a novel and robust CTA parameter to identify an intramural course of interarterial ACAOS. An ILS of <0.95 mm is indicative of an intramural segment.

Activation and allosteric regulation of the orphan GPR88-Gi1 signaling complex

GPR88 is an orphan class A G-protein-coupled receptor that is highly expressed in the striatum and regulates diverse brain and behavioral functions. Here we present cryo-EM structures of the human GPR88-Gi1 signaling complex with or without a synthetic agonist (1R, 2R)-2-PCCA. We show that (1R, 2R)-2-PCCA is an allosteric modulator binding to a herein identified pocket formed by the cytoplasmic ends of transmembrane segments 5, 6, and the extreme C terminus of the α5 helix of Gi1. We also identify an electron density in the extracellular orthosteric site that may represent a putative endogenous ligand of GPR88. These structures, together with mutagenesis studies and an inactive state model obtained from metadynamics simulations, reveal a unique activation mechanism for GPR88 with a set of distinctive structure features and a water-mediated polar network. Overall, our results provide a structural framework for understanding the ligand binding, activation and signaling mechanism of GPR88, and will facilitate the innovative drug discovery for neuropsychiatric disorders and for deorphanization of this receptor.

Allosteric coupling between transmembrane segment 4 and the selectivity filter of TALK1 potassium channels regulates their gating by extracellular pH

Opening of two-pore domain K+ channels (K2Ps) is regulated by various external cues, such as pH, membrane tension, or temperature, which allosterically modulate the selectivity filter (SF) gate. However, how these cues cause conformational changes in the SF of some K2P channels remains unclear. Herein, we investigate the mechanisms by which extracellular pH affects gating in an alkaline-activated K2P channel, TALK1, using electrophysiology and molecular dynamics (MD) simulations. We show that R233, located at the N-terminal end of transmembrane segment 4, is the primary pHo sensor. This residue distally regulates the orientation of the carbonyl group at the S1 potassium-binding site through an interacting network composed of residues on transmembrane segment 4, the pore helix domain 1, and the SF. Moreover, in the presence of divalent cations, we found the acidic pH-activated R233E mutant recapitulates the network interactions of protonated R233. Intriguingly, our data further suggested stochastic coupling between R233 and the SF gate, which can be described by an allosteric gating model. We propose that this allosteric model could predict the hybrid pH sensitivity in heterodimeric channels with alkaline-activated and acidic-activated K2P subunits.

Energy harnessing in the snap-through motion of a flexural-tensegrity flagellum

Flexural tensegrity is a structural concept according to which the flexural integrity of a chain of segments in unilateral contact is granted by one prestressing tendon (cable), whose elongation is varied by the relative segmental rotations as a function of the shape of the contact profiles. The elastic strain energy of the tendon, which can be tuned by springs added in series, dictates the constitutive response in bending of the flexural-tensegrity assembly. Here, we show that increasing the internal mobility of the tendon inside hollow segments allows for multi-stable equilibrium configurations. In particular, appropriately designed segmental cavities can induce a complex multi-articulated snap-through motion of long chains of segments, consequent to the harnessing of the elastic energy associated with the relative rotation of only one pair of segments. The motion can be reversed by changing the sign of the relative rotation. The dynamical problem is theoretically solved and results are compared with experiments on 3D-printed prototypes for a cantilever configuration, which behaves like a tail that flagellates in response to the cyclic rotation of the pair of end segments. This concept design can find applications in collapsible–deployable micro- and macro-structures, robotics, metamaterials with memory.

Formula omitted] and [formula omitted] continuous rational motions using a conformal geometric algebra

Traditional rational motion design describes separately the translation of a reference point in a body and the rotation of the body about it. This means that there is dependence upon the choice of reference point. When considering the derivative of a motion, some approaches require the transform to be unitary. This paper resolves these issues by establishing means for constructing free-form motions from specified control poses using multiplicative and additive approaches. It also establishes the derivative of a motion in the more general non-unitary case. This leads to a characterization of the motion at the end of a motion segment in terms of the end pose and the linear and angular velocity and this, in turn, leads to the ability to join motion segments together with either C1- or G1-continuity.

Interaction between historical earthquakes and the 2021 Mw7.4 Maduo event and their impacts on the seismic gap areas along the East Kunlun fault

On May 21, 2021 (UTC time), an Mw7.4 earthquake struck Maduo County, Qinghai Province, China. The rupture of this typical strike-slip event and its aftershocks along the Kunlun-Jiangcuo fault (JCF) propagated approximately 170 km from the epicenter. In this study, we calculated the coseismic and postseismic Coulomb stress changes induced by 14 historical earthquakes and investigated their impacts on the 2021 Maduo source area. We found that the JCF is in the stress shadow of these historical events with a combined ΔCFS range of approximately − 400 to − 200 kPa. Since the seismogenic fault of the 1937 event is nearly parallel and close to the JCF, the rupture of the 1937 event had the greatest inhibitory effect on Maduo source area. We hypothesize that the actual loading rate at the depth of the seismogenic layer in the Maduo source area is much higher than the simulated value (0.3 kPa/a). Consequently, the Maduo earthquake still occurred despite the considerable delaying effect of these historical earthquakes (especially the 1937 event). Our findings also indicate that the tectonic stress in the eastern Bayanhar block is still rapidly accumulating and adjusting. Our investigation further reveals the enhanced stress induced by the historical and Maduo events with ΔCFS values of approximately 30–300 kPa and 50–300 kPa on the Xidatan-Dongdatan segment (XDS) and the eastern end of the East Kunlun Fault (EKF), respectively, not only on the Maqin-Maqu segment (MMS) but also at the eastern end of each branch segment of the EKF. Hence, considering the accumulation of tectonic stress, we suggest that the seismic hazard in these two regions has been promoted.Graphic

A Bilevel Energy Management Strategy for HEVs Under Probabilistic Traffic Conditions

This work proposes a new approach for the optimal energy management of a hybrid electric vehicle (EV) considering traffic conditions. The method is based on a bilevel decomposition. At the microscopic level, the offline part computes cost maps due to a stochastic optimization that considers the influence of traffic, in terms of speed/acceleration probability distributions. At the online macroscopic level, a deterministic optimization computes the ideal state of charge at the end of each road segment using the computed cost maps. The optimal torque split can then be recovered according to the cost maps and this SoC target sequence. Since the high computational cost due to the uncertainty of traffic conditions has been managed offline, the online part should be fast enough for real-time implementation on board the vehicle. Errors due to discretization and computation in the proposed algorithm have been studied. Finally, we present numerical simulations using actual traffic data and compare the proposed bilevel method to the best possible consumption, obtained by a deterministic optimization with full knowledge of future traffic conditions, as well as to an established solution for energy management of a hybrid EV. The solutions show a reasonable overconsumption compared with deterministic optimization and manageable computational times for both the offline and the online part.

Geochronology, geochemistry and petrology of the oligocene magmatism in SE segment of the UDMB, Iran

Despite diverse geochronological-geochemical studies on Cenozoic igneous rocks from the SE segment of the Urumieh-Dokhtar Magmatic Belt (UDMB) of Iran, the nature of the Oligocene magmatic rocks from the farthermost end of the SE segment- where it is linked to the Makran magmatic belt- has been ignored due to the difficulty of access. In this study, we focus on syn-collisional mafic to felsic igneous rocks of calc-alkaline and high-K calc-alkaline affinities from the SE segment of the Urumieh-Dokhtar Magmatic Belt (UDMB) near Nagisun, south of Bam. The Nagisun rocks have low Sr/Y and La(n)/Yb(n), similar to igneous rocks from typical arcs. Zircon UPb ages show comparable ages for plutonic (~ 34–25 Ma) and volcanic (~34–27 Ma) rocks. The εHf(t) values for zircons from plutonic rocks range from −0.3 to +12.8, whereas the εHf(t) values for the volcanic rocks vary from −2.6 to +13. Modelling of trace elements compositions using Nagisan basaltic samples indicate that an 87:2:11 mixture of the depleted MORB mantle, subducting (trench)-sediments and altered oceanic crust with 5% aggregated fractional melting closely matches the trace-element abundances of the Nagisun basaltic rocks. Indeed, the modelling of Sr and Nd isotopic data emphasizes that the Nagisun magmatic rocks could be products of bulk mixing between a depleted MORB mantle and/or a mixed, fertilized mantle with the Cadomian lower and upper continental crust. Furthermore, our compiled data display that the magmatism in the SE segment of the UDMB changed through time from normal calc-alkaline magmatism to adakitic magmatism at ~20 Ma, after the collision with Arabia began ca 27 Ma.

The dimensions of an ensemble of collapsed disordered protein molecules under folding conditions

In order to detect the earliest formed intramolecular contacts in the refolding ensembles by detection of the intramolecular distances, we must first determine the dimensions of the transient collapsed ensemble. Does an ensemble of disordered molecules of foldable globular protein under folding conditions follow Flory's theory of collapsed polymers? Using E. coli Adenylate kinase (AK) as a model protein and microfluidic mixing device combined with time resolved FRET measurements (“the double kinetics” method) we tested the hypothesis that at the initiation of refolding, the dependence of the mean of the segmental end-to-end distance on the segment length, Δn, is weak (Δn>∼30).We measured the transient distributions of segmental end to end distances of seven segments of the AK molecule, with Δn from 45 to 196 residues at 50 μs after initiation of mixing.

Wear behavior and morphologic characterization of diamond segments induced by crystal plane characteristics of diamond grits in sawing hard materials

The wear of diamond grains (DGs) is a classic problem, affects the final cost, in sawing hard materials (granitic rocks) for slabs. However, the previous research rarely pays attention to study the wear of DGs considering the crystal plane characteristics. Hence, in this study, the aim is to explain the fracture morphology of DGs in sawing granitic rocks taking into account the crystal plane characteristics. The wear experiment was carried out with a frame saw. Then the surface morphology of DGs was characterized by scanning electron microscope (SEM). According to wear characteristics of DGs, the wear of DGs was divided into seven different types, including fresh, whole, micro fractured, pulled-out, flush with matrix, macro fractured and blunt. Interestingly, the bottom surface of the pulled-out DGs in contact with the matrix was mostly {100} crystal planes that account for approximately 80%. In addition, flush with matrix mostly occurred on the {111} crystal planes (account for 90%), and mostly at both ends of the diamond segments (DSs). Then, this phenomenon is explained by the interplanar spacing of DGs. Moreover, wear behavior and morphologic characterization of DGs were discussed considering the factors of stone sawing (e.g., detritus) and the characteristics of DGs (e.g., dislocation). Finally, wear evolution mechanism of DSs topography were proposed. This research enhances to deeply understand the wear of DGs in granite processing and provides guidance for the design of DSs.

Mantle melting, lithospheric strength and transform fault stability: Insights from the North Atlantic

The offset ridge-transform structure of ocean basins is one of the most prominent expressions of plate tectonics. Yet why this configuration is favored over a continuous divergent boundary has remained unresolved. We examine this issue using mantle Bouguer anomalies (MBAs) from contrasting ridge systems in the North Atlantic. The Reykjanes Ridge north of the Bight transform fault has no transform offsets and is characterized by rapidly propagating melting centers along a linear axis and a continuous MBA low. To the south, the adjoining Mid-Atlantic Ridge has typical ridge segments each underlain by a discrete MBA “bulls-eye” low and offset by transform and non-transform discontinuities. We hypothesize that the pattern of mantle melting, as reflected in the MBAs, creates chemical and rheologic variations in the residual mantle that either favor or hinder transform fault formation. Within ridge segments, mantle melting efficiently extracts water producing dry and strong residual mantle. At segment ends, low extents of melting and inefficient melt extraction preserve damp and weak mantle. On the linear Reykjanes Ridge continuous melting and rapidly propagating melting centers create continuous strong mantle with possibly weak rheologic variations at high angles to the opening direction, not favoring transform faults. In contrast, stable segmented mantle melting on the Mid-Atlantic Ridge forms bands of strong and weak residual mantle aligned in the spreading direction, the latter creating favorable locations for shear deformation and transform faults. Our hypothesis also explains the lack of transform faults at Earth's endmember spreading rates. At ultra-slow ridges, overall melting is limited and irregular and melt extraction is inefficient. At ultra-fast ridges, mantle melting is pervasive and melt extraction is efficient. In both cases, organized spreading-parallel compositional rheological variations do not form and transform faults are not favored. Our model implies that beyond cooling and strengthening with age, the pattern of mantle melting shapes the rheological structure of oceanic lithosphere and the geometry of plate tectonics.

ОБ ИДЕНТИФИКАЦИИ КОЭФФИЦИЕНТА ТЕПЛООБМЕНА В СЛОИСТОЙ СРЕДЕ

In the article we consider the well-posedness in Sobolev spaces of the inverse problems of determining the heat exchange coefficient at the interface which is included in the transmission condition of the imperfect contact type. In a cylindrical spatial domain, a second-order parabolic equation is considered. The domain is divided into two sub-domains, on the common part of the boundary of which the transmission condition is set. The heat exchange coefficient included in the transmission condition is sought as end segment in series with time-dependent unknown Fourier coefficients. The equation is supplemented with general boundary conditions and initial conditions, as well as overdetermination conditions. The ovedetermination conditions are the values of a solution at some points lying in the spatial domain. Under natural smoothness conditions for the data and the location of the measurement points, the existence and uniqueness theorem local in time is demonstrated. The obtained solution to the problem is regular, i. e., all generalized derivatives included in the equation are summable to some power, and the equation holds almost everywhere. The method is constructive, and the approach allows to develop numerical methods for solving the problem. The proof is based on a priori estimates obtained and the fixed-point theorem.

Method of the Earth Fault Location in Power Distribution Network Besed on Mearing Earth Conductor Current

The copper foil shielding layer and armoring layer of the three-core cable and the grounding electrode of the distribution network constitute the grounding network of the distribution network. When a grounding fault occurs in the power grid, a regular ground current distribution is formed in the grounding network. .This paper analyzes the distribution law of the ground wire current in the arc suppression coil and resistance grounded distribution network: for the distribution network with the neutral point through the arc suppression coil and resistance grounded, the active component of the ground wire current of all cable segments without ground faults is Pass-through, that is, the active components of the ground current at the head and end of the cable are equal in magnitude and in the same direction; the sum of the active components of the ground current at the head and end of the ground fault cable segment is equal to the active component of the fault current at the ground fault point. According to this distribution law, this paper proposes a ground fault location method in which the neutral point is grounded by the arc suppression coil and resistance grounded grid, and its effectiveness is verified by simulation.

Обобщенные решения краевых задач для уравнения Даламбера с локальнымии связанными граничными условиями

The initial-boundary value problems for the wave equations with local and non-local linear boundaryconditions at the ends of a general segment are considered. To solve them, a generalize functions method has beendeveloped, which translates the original boundary value problems to solving the wave equation with a singular right-handside containing a singular simple and double layers, the densities of which are determined by the boundary and initial valuesof the desired function and its derivatives. Received integral representation of the solution in terms of boundary functions,which are a generalization of Green’s formula for solutions of the wave equation. To determine the unknown boundaryfunctions, it is built in space Fourier transforms in time, a two-leaf resolving system linear algebraic equations, whichconnects 4 boundary values solution and its derivatives. Together with two boundary conditions of local and non-localtype, a resolving system of equations is built for solving the stated initial-boundary value problems. On its basis, givenanalytical solutions for classical three boundary value problems with conditions Dirichlet, Neumann and mixed at the endsof the segment. The developed method allows solving boundary value problems with different local and nonlocal boundaryconditions and must find an application change in solving wave and other equations on graphs of different structures.

Numerical investigation of hybrid UHPC columns subject to lateral impact

This paper presents extensive numerical and parametric studies on the dynamic performance of axially-loaded hybrid ultra-high-performance concrete (UHPC) columns subject to low-velocity impact loading. While existing studies have been performed on columns comprised fully of UHPC, the case of hybrid UHPC columns has not been fully explored. Hybrid columns involve the localised use of UHPC in combination with normal strength concrete (NSC) and can result in both performance and economic efficiencies. The present study uses Abaqus to develop a validated finite element (FE) model which allows exploration of key parameters such as impact location and energy, slenderness ratio and the length of the UHPC zone and their effect on hybrid column behaviour. It was found that localised adoption of UHPC at the predicted impact location significantly enhanced the performance and resulted in a change from brittle shear failure to flexural failure with minimal damage. The length of the UHPC segment was also found to have greater effect on columns with low reinforcement ratio. Meanwhile, the impact location was shown to have significant influence on the column response especially under a low pre-loading level. Hybrid columns experienced less displacement and higher plateau impact load under low impact energy. In comparison to the normal strength concrete column, the hybrid columns exhibited reduced mid-span displacement and increased impact load capacity which confirmed the ability of the UHPC segment to reduce the local damage resulting from the impact. In addition, in many cases, it was found that the application of higher pre-loading levels can provide an improvement in total impact performance of the hybrid columns. This is mainly attributed to the shifting of the pre-loading axis as a result of cracking at the top of the column ends. Finally, the presence of a UHPC segment with various lengths can change the location of the main (central) plastic hinge to the end of the UHPC segment, this reflects the ability of UHPC in improving the entire response of hybrid columns.