Structural performance of circular hollow precast high-strength concrete-filled steel tube piles under cyclic flexural and varying high axial loads

Bearing behaviour of S700 high strength steel bolted connections after exposure to elevated temperatures

Machine-learning assisted prediction of the heat-affected material mechanical properties of Q550GJC high strength steel thick-plate in cruciform welded joints

Strain rate inhomogeneity, plastic instability and ductile fracture in advanced high-strength steels

Investigating superplastic deformation mechanisms in HC1000/1470DP advanced high-strength steel through high-temperature tensile and bulge forming tests

Effect of C2S and limestone powder contents on interfacial bond characteristics of high-strength steel fibers embedded in low-carbon mortars

Study on the stability and bearing capacity of high-strength steel C-section columns with complex longitudinal stiffeners

Fatigue life prediction of high-strength steel combined ultrasonic damage index and inverse Gaussian process

Effects of pre-fatigue damage on mechanical properties of high-strength steel: Research status and prospects

Static-dynamic constitutive relationships of high-strength steel fused cladding layers by Wire Arc Additive Manufacturing

This study aims to establish an integrated experimental–numerical framework for characterizing the deformation behavior of DP590 high-strength steel sheet. The framework combines experimental uniaxial tensile and Nakajima tests with finite element (FE) simulations to provide a comprehensive assessment of forming limits and fracture behavior. Forming limit curves (FLCs) and forming limit stress curves (FLSCs) were determined with the integrated approach and then validated numerically using the Hill’48 yield criterion together with both Swift and Voce hardening laws. Model calibration incorporated experimental data on directional mechanical properties to ensure that material anisotropy was accurately represented. The FE simulations demonstrated strong agreement with the experimental data across uniaxial, plane-strain, and biaxial loading paths. The Swift hardening law consistently predicted higher forming limit stresses and more accurate drawing-depth estimates than the Voce law, particularly under biaxial and plane-strain conditions. The novelty of this work lies in the simultaneous validation of both strain- and stress-based forming limits, combined with the quantitative prediction of drawing depths, which has rarely been reported for DP590 grade. The proposed framework improves the predictive accuracy of forming simulations and provides practical guidelines for material characterization and process optimization in the automotive and related manufacturing industries.

To enhance the lightweight level, crash safety, and production efficiency of automotive B-pillars, this paper proposes a structure-process collaborative design scheme for the integrated inner panel of carbon fiber reinforced polymer (CFRP) B-pillars, which replaces high-strength steel based on the “part integration” concept. Considering the constraints of layup and molding processes, a multi-level design (layup block, shape, and number of layers) and multi-scale optimization (layup angle and thickness) are conducted for the CFRP inner panel. The design optimization results show that the stiffness of the CFRP B-pillar inner panel under key working conditions such as three-point bending and compression is significantly higher than that of the original high-strength steel component. Meanwhile, a surrogate model combined with the improved particle swarm optimization–bacterial foraging optimization (PSO–BFO) algorithm is further adopted for multi-objective optimization. After optimization, the three-point bending stiffness and first-order bending mode of the CFRP B-pillar inner panel are increased by 43.9% and 121.1%, respectively, compared with the original scheme, while achieving a remarkable 70% weight reduction. Based on the optimized design, the proposed CFRP B-pillar inner panel is manufactured using an resin transfer molding (RTM, closed-mold molding) device. Three-point bending and modal tests are carried out on the fabricated CFRP B-pillar inner panel, and the comparative verification between simulation and test results shows an error of <10%. Finally, the CFRP B-pillar inner panel is integrated into the high-strength steel B-pillar assembly for drop weight impact testing, with a displacement error of only 7.65% between the test and simulation results. This effectively verifies the excellent energy absorption characteristics of the design and the accuracy of the simulation model. This study successfully achieves significant improvements in B-pillar stiffness and dynamic performance as well as substantial lightweighting, providing an important reference for the high-performance and lightweight design of automotive B-pillars.

Strain and temperature-controlled solid-state bonding in high-strength steel: model validation and application to void healing in laser cladding

Movable guardrail systems are increasingly used in work zones, reversible lanes, and temporary traffic operations; however, evidence on their crashworthiness, material performance, and operational reliability remains dispersed across multiple design typologies and regulatory frameworks. This PRISMA-compliant systematic review synthesizes 78 studies involving full-scale crash tests, validated finite-element simulations, field performance evaluations, and compliance evaluations under MASH, EN 1317, NCHRP 350, and AS/NZS 3845.1. The findings indicate that modular rigid barriers reliably achieve TL-3/TL-4 performance when joint alignment and foundation conditions are properly controlled; semi-rigid steel systems provide a practical balance between containment capacity and redeployability, but remain sensitive to post spacing and connector detailing; and flexible polymer systems are best suited for short-duration, low-speed applications. Material-focused research highlights the advantages of UHPC section refinement, high-strength steels, and hybrid FRP–metal configurations in enhancing energy absorption without exceeding occupant-risk thresholds. Across studies, connection integrity consistently emerges as the dominant factor governing redirection stability and working-width performance. Field evaluations confirm satisfactory operational performance in constrained environments, while life-cycle assessments identify refurbishment intervals and mass-related logistics as major cost contributors. This review provides an integrated, evidence-based synthesis and a structured engineering foundation for advancing next-generation movable barrier designs, testing protocols, and deployment strategies.

This study investigates the critical transformation temperatures of a high-strength API-grade steel through thermal analysis and software simulations; the precise determination of these temperatures is essential for enhancing the efficacy of subsequent experimental trials. Utilizing the ‘Quench Properties’ module of JMatPro® V14, characteristic transformations were identified between 950 °C and 25 °C under stable conditions. Heating rates of 5, 10, and 30 °C/s were applied to determine critical temperatures, with Ac1 ranging from 700 °C to 750 °C and Ac3 from 850 °C to 900 °C. Niobium content may influence Ac1 and Ac3, promoting the ferritic phase and elevating transformation temperatures at a heating rate of 30 °C/s. Conversely, a rate of 10 °C/s significantly influenced austenite formation, impacting the development of microconstituents that enhance both strength and elongation post-quenching. Furthermore, slow cooling was found to favor the premature formation of allotriomorphic ferrite, which hinders the transformation of austenite into bainite and martensite during accelerated cooling. Finally, this study corroborates that JMatPro® is a reliable tool for predicting critical temperatures and designing optimized thermomechanical processing routes.

In the current numerical simulation study of high-strength steel welding, ignoring the phase transformation plasticity effect in the coupling analysis led to a significant deviation between the simulated value of residual stress and the experimentally measured value. To investigate the influence mechanism of the Welding Residual Stresses (WRSs) of 30MnCrNiMo armor steel, the transformation plasticity (TP) coefficient (7.81 × 10-5 MPa-1) was measured via a Gleeble 3500, and a Finite Element Model (FEM) of thermal-metallurgical-mechanical coupling considering yield strength, volumetric strain and TP behavior in Solid-State Phase Transformation (SSPT) was developed. The results show that the volume expansion during the SSPT is the main factor for the shift in WRS from tensile to compressive. In contrast, the TP effect reduces the peak longitudinal tensile stress in the Heat-Affected Zone (HAZ) by 51 MPa. It also ultimately neutralizes the compressive component in this region. When the martensite fraction ranges from 0.12 to 0.45, transformation plastic strain becomes the dominant factor, leading to a characteristic evolution of longitudinal stress that initially decreases and subsequently increases. The FEM incorporating the TP effect successfully captures the dual reversals of residual stress in the HAZ. The average relative error between the simulated longitudinal stress and the experimental data obtained via X-ray diffraction (cosα method) is 8.8%. The TP coefficient database and the developed multi-field coupling model markedly enhance the predictive accuracy for WRS in 30MnCrNiMo steel, offering a robust theoretical foundation for the design of stress corrosion resistance and the service life assessment of welded joints in armored vehicles.

Abstract Directed energy deposition (DED)-Arc is suitable for the hybrid additive manufacturing, modification and repair of large metal components with high deposition rates. Residual stresses and distortion are of central importance when characterizing the manufactured components and the sensitive transition area between additive manufactured (AM) component and semi-finished product. Residual stresses caused by the thermal cycles during the manufacturing process can impair the mechanical properties of the manufactured parts and can lead to component failure, especially for high-strength steels. Therefore, understanding and controlling residual stresses, when combining different base and feedstock materials, is critical to improve the quality and efficiency of the hybrid DED-Arc process. This article deals with the influence of the build-up height on the residual stress distribution of additively manufactured components with a selected base and feedstock material from commercial high-strength steels. Using a robot-assisted DED-system and a controlled short arc, AM welding experiments were carried out with close to the application parameters at working temperature (200 °C) and heat input (650 kJ/m). Five hybrid AM specimens (AM wall on upright structural steel plate) were produced using a one bead per layer strategy and selected AM-wall heights between 15 and 300 mm. The influence of the AM build height on the longitudinal residual stress in the whole hybrid AM specimen (in welding direction) was analyzed and discussed. All experiments exhibit comparable stress distributions in the area of the substrate plate up to the heat-affected zone (HAZ) and the transition zone, regardless of the building height. The height significantly influences the residual stress distribution of the deposited AM-component. Tensile residual stresses with a maximum range between 300and 400 MPa were always found in the last approx. 18 component layers (upper 40 mm). This is due to restraint of the shrinking of the top layers by the layers below. The lower layers show homogeneous residual stress distributions characterized by low compressive stresses due to the process-related tempering during the deposition of each layer on top of each other. As a result, the significant difference between the various AM build-up heights of the hybrid AM specimens is the extent (or height) of this tempered zone with low compressive stresses. These correlations contribute to the understanding of residual stress development with increasing structure height or ratio of component heights of substrate semi-finished product and AM component in hybrid additive manufacturing.

Microstructural Evolution and Mechanical Performance of Laser Spot Welds in Advanced High-Strength Steels: Statistical Optimization via Response Surface Methodology

In this paper, high-strength high-nitrogen steel Cr18Mn15 was fabricated using centrifugal casting. High-temperature tensile tests were subsequently performed on the centrifugally cast material. Based on the dynamic material model (DMM), power dissipation and instability maps were constructed for the steel. The results revealed that the optimal processing conditions for Cr18Mn15 are within a temperature range of 940 °C to 980 °C and a strain rate range of 0.001 s−1 to 0.01 s−1. Flow instability was observed primarily under high strain rate conditions (1 s−1) at a lower temperature of 900 °C. Four constitutive equation models were established based on the experimental results, and the prediction accuracy was assessed by calculating their average absolute relative errors (AAREs) and correlation coefficients (r). It was found that the Modified-JC constitutive model could simultaneously take care of both accuracy and simulation convergence with an AARE of 17.823 and Pearson’s correlation coefficient (PCC) of 0.968. For the practical application of Cr18Mn15 high-nitrogen steel, a three-layer composite tube forming and a continuous rolling equipment were developed. The rolling and spreading process was simulated using finite elements, and the stress field, strain field, and temperature field in the spreading process were analyzed to determine the following optimum process parameters of the alloy: a temperature of 950 °C, a processing line speed of 1 m/s, and a preheating temperature of 200 °C.

Rapid tempering to enhance dynamic performance of high and ultra-high strength steels