Effects of Mechanical Properties of Steels on Dynamic Collapse Behavior of High Strength Steel Hat Columns

Abstract

We investigated the relationship between the material properties and axial collapse behavior of hat-section hollow columns made of highstrength steels. Dynamic collapse tests of the columns and FEM simulations were conducted using high-strength steels with various tensile strengths and n-values. Materials that exhibited yield point elongation (YPEl) underwent enhanced accordion-type deformation in axial collapse owing to the occurrence of long wave buckling on the hat walls in the early stage of collapse. In addition, it was important to avoid fracture in the initial buckling region to induce progressive crumpling behavior. A high n-value of the material was favorable for avoiding fracture by increasing the bend radii and decreasing the strain concentration at the buckling regions on the hat walls, thereby resulting in stable progression of accordion-type folds. In conclusion, steels exhibiting YPEl and high n-values are favorable for inducing stable accordion-type deformation during axial collapse.

Local Yield Stress and Its Unusual Independence on Multi-axial Stress States during Lüders Deformation of Medium-Mn, High-strength Steel

“…Therefore, given that the 𝜎 𝑡 −𝜌 curve of the test steel did not exhibit an upper yield point (Fig. 5), we employed the Swift work hardening law 30), 31) , which was simply offset by 𝜀 𝑝 = 𝜀 𝑦𝑙 under the Mises yield criterion and associated J2 flow rules. The work-hardening law is shown in Eq.…”

Best Papers Awarded in 2022 by <i>Materials Transactions</i>

“…In association with the awarded papers introduced above, popular topics that Materials Transactions published in recent years are grain boundary segregation 93) as Ito et al were concerned with, 4,30,49) creep deformation in a wide range of materials 94102) including tricrystals by Okada et al 103,104) and work hardening in various forms of deformation in an aluminum single crystal, 105) an A3104 aluminum alloy, 106) a Ti6Al4V alloy 107) and high-strength steels. 108) Furthermore, pitting corrosion resistance is also a popular issue reported by many research groups in terms of corrosion behavior of pure aluminum, 109) pure zirconium 110) and stainless steels. 111113) Readers who are interested in such topics may be worth checking them.…”

Best Papers Awarded by JILM and JSTP in <i>Materials Transactions</i>

“…Articles of 10-20 are annually published through JSTP in Materials Transactions: for example, 16 articles in 2021-2022. 4,5,[94][95][96][97][98][99][100][101][102][103][104][105][106][107] The awarded paper of Takahashi et al 1,60) through JILM is concerned with measurements of interdiffusion and impuritydiffusion coefficients in multicomponent Ti alloys, which are fundamental quantities to understand phenomena occurring at elevated temperatures. Indeed, comprehensive study was presented on the Ti-Al-Zr ternary system following their earlier studies on the Ti-Al-X (X = V, Cr, Fe, Co) ternary systems.…”