Crashworthiness of Composites and Lightweight Structures最新文献

{"title":"Global Characterization of Failure Modes Under Impact Loading in Structural Components Made of Low Ductility Materials","authors":"Shengyang Wu, Xiaoming Chen, Weiran Hu","doi":"10.1115/imece2001/amd-25437","DOIUrl":"https://doi.org/10.1115/imece2001/amd-25437","url":null,"abstract":"\u0000 This study reviews the impact failure modes of structural components made of materials with low ductility such as aluminum and magnesium. Tensile failure is observed at large stretch area or on the tension side of large bending deformation. Material breakage due to shear may also occur. There are several approaches to simulate the material failure process in explicit finite element software used for crashworthiness analysis. Evaluation of the effective applications of these material models is presented with a finite element simulation of bi-axial loading tests. The forming limit diagram is used to evaluate various failure criteria. Component crash simulations are presented to demonstrate the applications of failure criteria.","PeriodicalId":431388,"journal":{"name":"Crashworthiness of Composites and Lightweight Structures","volume":"450 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115615037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Some Results and Issues in the Non-Destructive Evaluation of Sandwich Composite Structures","authors":"E. Ayorinde, R. Gibson, Feizhong Deng","doi":"10.1115/imece2001/amd-25429","DOIUrl":"https://doi.org/10.1115/imece2001/amd-25429","url":null,"abstract":"\u0000 This paper focuses on the use of basic NDE methods like ultrasonics, imaging and vibration testing to assess the integrity of some sandwich composites which have been subjected to transverse loading. Samples of a foam core, glass composite facing sandwich beam of varying thicknesses and end notch lengths were tested in three point bending and assessed by these NDE methods. The results show that core shear and indentation failures appear to be the prominent failure modes for these geometries and materials, and that changes in the damping and vibration modal frequencies of the beams can indicate damage states.","PeriodicalId":431388,"journal":{"name":"Crashworthiness of Composites and Lightweight Structures","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127612206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deployment of Structural Foam in a Vehicle Roof System for Weight Reduction: Analytical/Experimental Verification","authors":"J. Alwan, Chi-Chin Wu, C. Chou","doi":"10.1115/imece2001/amd-25435","DOIUrl":"https://doi.org/10.1115/imece2001/amd-25435","url":null,"abstract":"\u0000 The effect of structural foam (both polyurethane foam and Epoxy-based foam) on roof-crush resistance, when injected in the cavities of principal roof crush components, is investigated. Previously established design guide-lines have been used to optimize foam benefits by selecting appropriate foam density, and location of foam application. Finally, feasibility of downgaging a roof-crush system through optimized foam deployment and without affecting strength is evaluated.\u0000 Two identical body-in-white (B-I-W) vehicles were used in this evaluation. One vehicle was considered as a base, while the other was injected with 9 pcf polyurethane foam at several critical locations. The foam density selection was based on the component study findings, while the foam location was determined based on a CAE analysis of the base model to locate plastic hinge formation and their sequence of occurrence. It was found that the maximum load was increased by 27% due to foam filling and the buckling strength increased by confining support. The total absorbing energy was increased by 25% due to the increase in the plastic moment capacity. Similar observations were registered when a 5 mm layer of Epoxy Based Foam was deployed in the same roof system.\u0000 CAE roof-crush analysis performed on the tested (B-I-W) came in good correlation with the test results. Similar CAE analysis was performed on another vehicle roof-crush model; the maximum load was reported to increase by 26% and the total absorbed energy increased by 22% when the vehicle was injected with 9 pcf polyurethane foam at the pre-determined locations. Finally, the latest model was downgaged selectively by 20% with a minimum thickness of 0.68 mm. This resulted in a total weight saving of 6 Kgs. CAE analysis showed that the resulting loss in functionality of the system due to downgaging (resistance in this case) was totally compensated by foam deployment at the predetermined locations.","PeriodicalId":431388,"journal":{"name":"Crashworthiness of Composites and Lightweight Structures","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121824720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Light Weight Steel Technology Used in a Vehicle Design: Safety CAE Analysis","authors":"J. Alwan, Chi-Chin Wu, Thomas H. Sheng, C. Li, Yi Liu","doi":"10.1115/imece2001/amd-25430","DOIUrl":"https://doi.org/10.1115/imece2001/amd-25430","url":null,"abstract":"\u0000 The automotive industry is facing new environmental requirements that call for more stringent rules to protect the environment and reduce material and resources usage. As such, the automotive industry is in more need to reduce fuel consumption and control emissions in order to meet the new environmental requirements. One of the methods that helps in acheiving lower fuel consumption targets is weight reduction. Making cars lighter sounds plausable, but is it acheivable without affecting vehicle Safety as well as other customer demands for more comfort and better vehicle performance (Criteria that are a must in today’s stringent safety requirements and competitive environment.). The body-in-white (BIW) accounts for about 25% of the total vehicle weight, and thus it provides a great opportunity for weight reduction. However, the challenge is not only to reduce the vehicle’s BIW weight, but also to maintain competitive vehicle functionality in Safety, NVH and Durability.\u0000 The studied technologies include: Generic Body Architecture, Tailor Welded Blanks, Ultra High Strength Steel, Structural Foams, and Structural Adhesives. Each of these technologies was benchmarked in terms of weight savings, vs Safety, NVH, and Durability functionalities. The models that were used for the technology prove outs are based on generic modified Body Architecture CAE models. It was shown that the total weight savings acheived from architecture alone was 24 lb (out of 707 lb initial BIW weight, thus making the weight savings close to 3.4%). In addition, the combination of Tailor welded blanks and Ultra high strength steel has resulted in an 80 lb reduction in the BIW weight, which is close to 11.3%. Structural foams showed an effective increase in roof crush strength, and showed potential enhancement for frontal crash pulses as well as potential shortening of front ends. On the other hand, structural adhesives showed enormous NVH benefits in stiffness with as little as 1% energy absorption enhancement for crash. Thus producing the perfect method to compensate the reduced body stiffness due to sheet metal gage reduction and replacement with Ultra High strength steel. By such both safety and NVH functionalities are complemented without weight increase.","PeriodicalId":431388,"journal":{"name":"Crashworthiness of Composites and Lightweight Structures","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132825948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic Mechanical Properties of Fiber-Metal Laminates","authors":"Jianjun Liu, B. Liaw, Manish Pamwar","doi":"10.1115/imece2001/amd-25424","DOIUrl":"https://doi.org/10.1115/imece2001/amd-25424","url":null,"abstract":"\u0000 Fiber-metal laminated cantilever beams, made of glass-fiber reinforced GLARE and aramid-fiber reinforced ARALL laminates interlaced with aluminum layers, were first excited by a shaker at various frequencies surrounding resonances. Dynamic Young’s moduli and damping ratios were then evaluated using both free-vibration (resonance) and forced-vibration (non-resonance) schemes. Results from both schemes are in good agreement. Compared to aluminum alloys, the dynamic Young’s moduli of fiber-metal laminates are relatively lower. For all types of fiber-metal laminates tested in this study, their values are almost constant within an excitation frequency range up to 5,000 Hz whereas the damping ratios oscillate within a narrow range of 0 to 0.02. The obtained dynamic moduli are in excellent agreement with their static counterparts. Better results were obtained when using a strain gage near the clamped end, as compared to a piezoelectric accelerometer at the tip.","PeriodicalId":431388,"journal":{"name":"Crashworthiness of Composites and Lightweight Structures","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129682559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}