Design of lightweight magnesium car body structure under crash and vibration constraints

Car body design in view of structural performance and lightweighting is a challenging task due to all the performance targets that must be satisfied such as vehicle safety and ride quality.In this paper,material replacement along with multidisciplinary design optimization strategy is proposed to develop a lightweight car body structure that satisfies the crash and vibration criteria while minimizing weight.Through finite element simulations,full frontal,offset frontal,and side crashes of a full car model are evaluated for peak acceleration,intrusion distance,and the internal energy absorbed by the structural parts.In addition,the first three fundamental natural frequencies are combined with the crash metrics to form the design constraints.The wall thicknesses of twenty-two parts are considered as the design variables.Latin Hypercube Sampling is used to sample the design space,while Radial Basis Function methodology is used to develop surrogate models for the selected crash responses at multiple sites as well as the first three fundamental natural frequencies.A nonlinear surrogate-based optimization problem is formulated for mass minimization under crash and vibration constraints.Using Sequential Quadratic Programming,the design optimization problem is solved with the results verified by finite element simulations.The performance of the optimum design with magnesium parts shows significant weight reduction and better performance compared to the baseline design.

PHYSICAL VALUE MAPPING ALGORITHM OF MESH IN FINE CAE ANALYSIS OF AUTOMOBILE BODY STRUCTURE

A physical value mapping （PVM） algorithm based on finite element mesh from the stamped part in stamping process to the product is presented, In order to improve the efficiency of the PVM algorithm, a search way from the mesh of the product to the mesh of the stamped part will be adopted. At the same time, the search process is divided into two steps： entire search （ES） and local search （LS）, which improve the searching efficiency. The searching area is enlarged to avoid missing projection elements in ES process. An arc-length method is introduced in LS process. The validity is confirmed by the results of the complex industry-forming product.

Uncertainty Optimization Design of a Vehicle Body Structure Considering Random Deviations

In vehicle body manufacturing,there are small differences between the actual value and design value of,for example,plate thickness and material characteristics.This is caused by the processing technology,environment and other uncertain factors.Therefore,the performance of the vehicle body processed according to the deterministic optimization solution fluctuates.The fluctuations may make structural performance fail to meet the design requirements.Thus,in this study,an optimization design is executed with 6σrobustness criteria and a Monte Carlo simulation single-loop optimization strategy based on the radial basis function neural network approximate model considering deviations in plate thickness,elastic modulus,and welding spot diameter,which is called the uncertainty optimization design method.As an example,considering the bending stiffness,torsion stiffness,and first-order frequency as constraints,the method is applied to the lightweight design of a car body structure,and the reliability of deterministic optimization design and uncertainty optimization design is compared.The results demonstrate that the uncertainty optimization design solution is effective and feasible without lowering the static stiffness and modal performance,and the weight is reduced.

Failure characteristics and the damage evolution of a composite bearing structure in pillar-side cemented paste backfilling

A backfilling body-coal pillar-backfilling body(BPB)structure formed by pillar-side cemented paste backfilling can bear overburden stress and ensure safe mining.However,the failure response of BPB composite samples must be investigated.This paper examines the deformation characteristics and damage evolution of six types of BPB composite samples using a digital speckle correlation method under uniaxial compression conditions.A new damage evolution equation was established on the basis of the input strain energy and dissipated strain energy at the peak stress.The prevention and control mechanisms of the backfilling body on the coal pillar instability were discussed.The results show that the deformation localization and macroscopic cracks of the BPB composite samples first appeared at the coal-backfilling interface,and then expanded to the backfilling elements,ultimately appearing in the coal elements.The elastic strain energy in the BPB composite samples reached a maximum at the peak stress,whereas the dissipated energy continued to accumulate and increase.The damage evolution curve and equation agree well with the test results,providing further understanding of instability prevention and the control mechanisms of the BPB composite samples.The restraining effect on the coal pillar was gradually reduced with decreasing backfilling body element's volume ratio,and the BPB composite structure became more vulnerable to failure.This research is expected to guide the design,stability monitoring,instability prevention,and control of BPB structures in pillar-side cemented paste backfilling mining.

On the physical model of earthquake precursor fields and the mechanism of precursors＇timespace distribution──origin and evidences of the strong body earthquake──generating model

According to the requirement of the project 'Establishment of the Physical Model of Earthquake PrecursorFields',this paper elucidates the train of thinking for research on the project and some scientific problems whichmust be studied i, the elucidation emphasizes that the core of this project is to study the conditions and processesof the generation of strong earthquakes. The paper first outlines the origin and development of the'strong-bodyearthquake-generating model' proposed by the author in the 1980;and then proves the reasonableness of themodel from three aspects, namely: deep structures, mechanical analysis and rock fracture experiments. Bystudying the tomographic image for the northern part of North China, it can be seen that the sources of strongearthquakes are all distributed in high-velocity bodies,or in the contact zone between high-velocity and lowvelocity bodies but nearer to the high-velocity body. It has been affirmed through studies of the mechanical modelsof hard and soft inclusions that the existence of a hard inclusion is an imPOrtant condition for the high concentration of large amounts of strain energy. A lot of theoretical and experimental studies have been made to investigate the conditions for rock instability; the results have consistently indicated that rock instability,sudden fracture and stress drop would be possible only if the stiffness of the source body is greater than the environmentalstiffness.

Information in the Universal Triangle of Reality for Non-living/Living Structures:From Philosophy to Neuro/Life Sciences

With the purpose to understand better the role of information not only in communication systems,but actually in our environmental reality,this paper presented the model of Universal Triangle of Reality,composed by Matter,Energy and Information,as fundamental constitutive components of this reality.Arguments coming from the field of physics,both at the cosmic and microparticles scale are presented,showing undoubtable conclusions that information is a fundamental component of reality in our material world.At the cosmic level,where the unusual high concentration of mass in the black holes constitutes a special state of matter,suitable for analysis of their special properties,the problem of the conservation principle of information is discussed.At the quantum level,the special unusual characteristics derived from the non-localization principle are also highlighted,together with information-involved problems and solutions.The Universal Triangle of Reality in the living systems reveals the high role of the involved information,both as the informational common organization on the entire evolution scale,and as the info-dynamics processes inside of own structure and resulted from interaction with the environment.The relevant advances in the approaching and understanding of the functionality of the living systems from informational point of view are highlighted,showing the high contribution of information concepts in understanding/solving of various older/recent problems in philosophy,neuroscience/neurology/psychiatry,neuro-physics/neuropsychology/behavior sciences,geriatrics/gerontology,biology and life sciences.

Evolution and Development of the Information Concept in Biological Systems: From Empirical Description to Informational Modeling of the Living Structures

With the purpose to smooth the way of a correct understanding of information concepts and their evolution,in this paper,is discussed the evolution and development of the concept of information in biological systems,showing that this concept was intuitively perceived even since ancient times by our predecessors,and described according to their language level of that times,but the crystallization of the real meaning of information is an achievement of our nowadays,by successive contribution of various scientific branches and personalities of the scientific community of the world,leading to a modern description/modeling of reality,in which information plays a fundamental role.It is shown that our reality can be understood as a contribution of matter/energy/information and represented/discussed as the model of the Universal Triangle of Reality(UTR),where various previous models can be suggestively inserted,as a function of their basic concern.The modern concepts on information starting from a theoretic experiment which would infringe the thermodynamics laws and reaching the theory of information and modern philosophic concepts on the world structuration allow us to show that information is a fundamental component of the material world and of the biological structures,in correlation with the structuration/destructuration processes of matter,involving absorption/release of information.Based on these concepts,is discussed the functionality of the biologic structures and is presented the informational model of the human body and living structures,as a general model of info-organization on the entire biological scale,showing that a rudimentary proto-consciousness should be operative even at the low-scale biological systems,because they work on the same principles,like the most developed bio-systems.The operability of biologic structures as informational devices is also pointed out.

Interpretation of residual gravity anomaly caused by simple shaped bodies using very fast simulated annealing global optimization

A very fast simulated annealing（VFSA） global optimization is used to interpret residual gravity anomaly.Since,VFSA optimization yields a large number of best-fitted models in a vast model space;the nature of uncertainty in the interpretation is also examined simultaneously in the present study.The results of VFSA optimization reveal that various parameters show a number of equivalent solutions when shape of the target body is not known and shape factor ＇q＇ is also optimized together with other model parameters.The study reveals that amplitude coefficient k is strongly dependent on shape factor.This shows that there is a multi-model type uncertainty between these two model parameters derived from the analysis of cross-plots.However,the appraised values of shape factor from various VFSA runs clearly indicate whether the subsurface structure is sphere,horizontal or vertical cylinder type structure.Accordingly,the exact shape factor（1.5 for sphere,1.0 for horizontal cylinder and 0.5 for vertical cylinder）is fixed and optimization process is repeated.After fixing the shape factor,analysis of uncertainty and cross-plots shows a well-defined uni-model characteristic.The mean model computed after fixing the shape factor gives the utmost consistent results.Inversion of noise-free and noisy synthetic data as well as field data demonstrates the efficacy of the approach.

Body size structure of Pleistocene mammalian communities: what support is there for the “island rule”?

Islands are often regarded by scientists as living laboratories of evolution and an optimal context for the study of forces influencing evolution and diversification.Two main issues have been attentively scrutinized and debated:the loss of biodiversity and the peculiar changes undergone by island settlers,primarily changes in size of endemic vertebrates.Over time,several hypotheses have been formulated to explain the causal mechanism of body size modification.Faunas of those islands where mainland taxa migrate more than once provide the most interesting data to answer the question of whether or not trends of insular taxa result from a predictable response to differences in competition and availability of niches between insular and mainland environments.To contribute to the debate,the body size structure of the Pleistocene mammalian faunas from two Mediterranean islands,Sicily and Crete,were analyzed and compared with the structure of coeval mainland faunas.The results obtained suggest that:(i)size of endemic species does not directly depend on the area of islands;(ii)evolution and size of endemic species seems somewhat affected by the degree of isolation(constraining coloniza-tion from mainland)and physiography(sometimes permitting adaptive radiation);(iii)in unbalanced insular communities,the shift in size of non-carnivorous species largely depends on the nature of competing species;and(iv)body size of carnivorous species mainly depends on the size of the most available prey.Consequently,it is rational to suppose that the body size of insular mammals mainly results from the peculiar biological dynamics that characterizes unbalanced insular communities.Ecological interaction,particularly the intraguild competition,is the major driver behind the evolution of insular communities,leading towards an optimization of energy balance through a change in body size of endemic settlers.

Innovative Electric Vehicle Body Design Based on Insurance Institute for Highway Safety Side Impact Conditions

A version of an electric vehicle was developed and designed for the US market on the basis of the required domestic body structure.When compared with the original car,the new car body design leads to two major technical difficulties.First,the installation of high-voltage components such as the battery pack and other new energy sources increases the vehicle weight and occupies a great deal of its structural space;this limits the impact paths and the use of traditional structural designs,which greatly increases the design difficulty.Second,the USA,as an advanced automobile-using country,has well-developed laws and regulations for collision standards,vehicle operating conditions and evaluation standards.Using a combination of butterfly diagram analysis,bending moment management,section forces and other computer-aided simulation and analysis techniques,this paper presents a body structure design that can achieve a“GOOD”evaluation under the US Insurance Institute for Highway Safety(IIHS)side impact body structure conditions by optimizing the force transfer path,the B-pillar deformation mode and the threshold support structure.The threshold support structure supports realization of the“GOOD”rating for IIHS side impact and helps the body to meet the crash requirements of the Federal Motor Vehicle Safety Standard FMVSS214 and the US New Car Assessment Program(NCAP)requirements for side impact at 32 km/h and 75°angular pole impact.

Unconformity structures controlling stratigraphic reservoirs in the north-west margin of Junggar basin, North-west China

Tectonic movements formed several unconfor- mities in the north-west margin of the Junggar basin. Based on data of outcrop, core, and samples, the unconformity is a structural body whose formation associates with weath- ering, leaching, and onlap. At the same time, the structural body may be divided into three layers, including upper layer, mid layer, and lower layer. The upper layer with good primary porosity serves as the hydrocarbon migration system, and also accumulates the hydrocarbon. The mid layer with compactness and ductility can play a role as cap rock, the strength of which increases with depth. The lower layer with good secondary porosity due to weathering and leaching can form the stratigraphic truncation traps. A typical stratigraphie reservoir lying in the unconformity between the Jurassic and Triassic in the north-west margin of the Junggar basin was meticulously analyzed in order to reveal the key controlling factors. The results showed that the hydrocarbon distribution in the stratigraphic onlap reservoirs was controlled by the onlap line, the hydro- carbon distribution in the stratigraphic truncation reser- voirs was confined by the truncation line, and the mid layer acted as the key sealing rock. So a conclusion was drawn that ＂two lines （onlap line and truncation line） and a body （unconformity structural body）＂ control the formation and distribution of stratigraphic reservoirs.