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Press hardenable ultra high strength steel (UHSS) is commonly used for automotive components to meet crash requirements with minimal mass addition to the vehicle. Press hardenable steel (PHS) is capable of forming complex geometries with deep sections since the forming takes place at elevated temperatures up to 900 degrees Celsius (in the Austenitic phase). This forming process is known as hot-stamping. The most commonly used PHS grade is often referred to as PHS1500. After hot-stamping, it is typically required to have a yield strength greater than 950 MPa and a tensile strength greater than 1300 MPa. Most automotive design and material engineers are familiar with PHS, the hot-stamping process, and their capabilities. What is less known is the capability of 3rd Generation advanced high strength steels (AHSS) which are cold stamped, also capable of forming complex geometry, and are now in the process of, or have recently completed, qualification at most automotive manufacturers.

The ThyssenKrupp InCar Project is a comprehensive R&D development that gives automotive manufacturers modular solution kits for body, chassis and powertrain applications. The solution kits developed within this project offer weight reduction, cost savings or improved functionality. This paper will focus on the two front door solutions developed within the InCar project. The first door solution, called the Lightweight Door, achieved a 13% weight reduction. This door features a 4-piece tailored blank inner panel and a sandwich material outer panel. The second door solution, called the Advanced Door, is a completely new and innovative door architecture that uses a 2-piece tailored blank mid panel and ultra thin Dual Phase 500 outer panel to achieve an 11% weight reduction. Prototypes were manufactured and tested for both door solutions.

The ThyssenKrupp InCar Project is a comprehensive R&D development that gives automotive manufacturers modular solution kits for body, chassis, and powertrain applications. The solution kits developed within this project offer weight reduction, cost savings, or improved functionality. This paper will focus on the front longitudinal members of the body structure. The front longitudinal member is a key safety component responsible for absorbing energy in a frontal crash event. It must also have high local strength, stiffness, and fatigue resistance at the suspension attachment points. Within the InCar project, several different solutions for the front longitudinal members were developed, including stamped AHSS concepts, stamped AHSS tailored blank concepts, and tailored tube concepts using an innovative forming technology for closed section designs, called InForm T3 (Thyssen Tailored Tubes).

To improve the energy absorption capacity of front-end structures during a vehicle crash, a novel 12-sided cross-section was developed and tested. Computer-aided engineering (CAE) studies showed superior axial crash performance of the 12-sided component over more conventional cross-sections. When produced from advanced high strength steels (AHSS), the 12-sided cross-section offers opportunities for significant mass-savings for crash energy absorbing components such as front or rear rails and crush tips. In this study, physical crash tests and CAE modeling were conducted on tapered 12-sided samples fabricated from AHSS. The effects of crash trigger holes, different steel grades and bake hardening on crash behavior were examined. Crash sensitivity was also studied by using two different part fabrication methods and two crash test methods. The 12-sided components showed regular folding mode and excellent energy absorption capacity in axial crash tests.

The primary goal of closure design is to achieve a functional, lightweight assembly, while also meeting stiffness, crash, and dent resistance targets. Typical automotive closure assemblies, such as liftgates, decklids, hoods, and doors, usually consist of an inner panel, outer panel, and miscellaneous reinforcements. There are also many attachment methods used; hem flange, spot-weld, laser weld, adhesive, hinges, latches, struts, and bolts. This paper investigates the weight reduction benefits gained from utilizing structural foam to increase stiffness performance. Finite element analysis (FEA) is applied to baseline and redesigned versions of a liftgate, door, and decklid assembly to measure the stiffness performance with structural foam application. Performance is measured in terms of maximum displacement and Von Mises stresses incurred from several loading conditions.

A typical forming operation of chassis components (control arms, cross members, etc.) often involves edge stretching and/or hole expansion. As a result, the edge split is a common forming failure mode. To overcome this problem, Japanese and European automakers use stretch flange high strength (SFHS) steel due to its high strength and excellent edge stretch capability. Recently, SFHS steel has gained greater attention in North America and is currently being used for upper and lower control arm applications. This paper includes a discussion on general edge stretch issues in forming operations, including material data that demonstrate the higher stretch limit of SFHS steel as compared to other high strength steels. In a case study, SFHS steel is applied to a control arm and finite element analysis (FEA) is conducted to evaluate forming and structural performance.

The purpose of this paper is to show that certain steel skid plates can achieve up to a 50% weight reduction, with little or no increase in cost, by simply changing the shape and utilizing high strength steel. There are many factors that can influence the skid plate shape, including rail width, ground clearance, attachment points, drive shaft location, and the general shape of the object for which it is the skid plate's sole purpose to protect (fuel tank, transfer case, etc.). A skid plate is usually considered last from a design standpoint so that its design is dependent upon the environment which it is set in. For this reason, skid plates are generally heavy and flat to meet ground clearance requirements and have ribs inserted to increase stiffness. Sometimes design parameters require a skid plate to be heavy and flat. But more often, a stiffer lightweight design can be obtained.

Dual Phase (DP) high strength steel is widely used in Europe and Japan for automotive component applications, and has recently drawn greater attention in the North American automotive industry for improving crash performance and reducing weight. In comparison with high-strength low-alloy (HSLA) steel grades with similar initial yield strength, DP steel has the following advantages: higher strain hardening, higher energy absorption, higher fatigue strength, higher bake hardenablility, and no yield point elongation. This paper compares the performance of DP and HSLA steel grades before, during, and after hydroforming. Computer simulation results show that DP steel demonstrates more uniform material flow during hydroforming, better crash performance and less wrinkling tendency.