Tham khảo tài liệu 'illustrated sourcebook of mechanical components part 15', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 29-2Ó Quick Calculations for Corrugation Stiffness Equations and graph find moment of inertia and location of neutral axis for a wide range of cross-sections. Earl A. Phillips Pressed Corrugotion Model Used to Derive Equations Corrugations add stiffness to sheets and plates but how much One of the equations given here quickly and accurately estimates the additional stiffness by solving for moment of inertia of the cross-section. And to help in calculating stresses a second equation finds the neutral axis in the corrugated sheet. The equations were derived for pressed corrugations top sketch . Sheets corrugated in this manner do not undergo any reduction in width. Horizontal parts remain as thick as they were in the original sheet but when the convolutions are formed by stretching the webs become thinner. Another method of corrugation reduces the width of the finished sheet but retains a constant thickness throughout bottom sketch . Tire equations hold for these constant-thickness corrugations as well except when the corrugations are nearly rectangular then the equations are accurate for the pressed corrugations only. As a guide to using the graph representative crosssections have been sketched in to show where they fall. EQUATIONS Height of neutral axis above reference line y 0 ỹ Kilữ - K - KtKì 2 Moment of inertia I LP KpA 1 12 LPB 12 A is found from the graph on page 77. B is a magnification factor that tells how many times stronger the corrugation has made the sheet. If comparisons and not absolute values arc needed simply compute B for each corrugation cross-section. SYMBOLS A Parameter depending on A l and Kt B Ratio stiffness of corrugation to stiffness of flat sheet K A 4- 1 d Depth of corrugation in. 1 Moment of inertia Ki Ratio d t Kt Ratio u IF Kt Ratio W L L Corrugation pitch length in. t Thickness of sheet in. w Width of bottom of corrugation in. IF Width of top of corrugation in. y Height of neutral axis in.
