Material selection and structural design of highway lightweight guardrail
Traditional carbon steel guardrails have the disadvantages of high weight per unit volume,high car-bon emissions during production and transportation,low product reuse rate,and easy entry of vehicles into op-posite lanes in collision accidents.A new type of stainless steel(QN1701)was selected as a lightweight guard-rail material.Chemical composition analysis shows that it has the characteristics of high manganese,high chro-mium and high PREN value.Its tensile strength reaches 740 MPa,yield strength is 430 MPa,and its elonga-tion is 54%,which is 56%～72%higher than the corresponding mechanical index of traditional carbon steel(Q235),and therefore has higher structural safety.According to the theoretical calculation of Newmark-β method,the QN1701l guardrail structure system can effectively reduce the severity of the collision and protect the vehicle from rushing out of the guardrail.The guardrail structure with the design protection class being SB is 48.3%lighter than that of Q235 carbon steel guardrail.Numerical simulation results show that the safety performance of the new stainless-steel guardrail meets the requirements of SB-level crash worthiness.
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