Direct Micro Mechanical Testing Method for MEMS Materials

2005 ◽  
Author(s):  
Bo Li ◽  
Quanfang Chen
Keyword(s):  
Mechanical Testing ◽  
Fracture Strength ◽  
Mechanical Test ◽  
Optimized Design ◽  
Element Analysis ◽  
Specimen Handling ◽  
Micro Scale ◽  
Brittle Behavior ◽  
Testing Method ◽  
Simple Boundary

Mechanical properties of MEMS materials are crucial for MEMS performance and reliability. Micro scale mechanical test has been challenging to MEMS community, due to the difficulties in handling micro scale specimens. In this article, a novel micro mechanical tensile testing method has been developed in combining a stiff microscale specimen developed with MTS Tytron Micro Force Tester. The advantages of this method include that it is a standard direct test of micro machined specimens, simple boundary conditions, and easy specimen handling/mounting in characterization. A novel specimen with micro features has been designed and fabricated for the direct mechanical testing. The specimen consists of three micro beams in parallel. The width of the center beam is 40 μm and the outer two beams’ width is 90 μm. The length of all three beams is 4 mm long. An optimized design has been achieved with finite element analysis, which shows that 98% of the total deformation occurs on the beams’ gage length. The stress is uniformly distributed over the three beams with a difference less than 0.5% among them. Both UV-LIGA fabricated nickel and SU-8 specimens have been tested. The UV-LIGA fabricated nickel has fracture strength of 1000±70 MPa and the results of SU-8 show a brittle behavior with fracture strength of 48±3 MPa.

Development of In-Situ Mechanical Testing Method for SOFC Components

2010 ◽  
Author(s):  
Satoshi Watanabe ◽  
Kazuhisa Sato ◽  
Yohei Takeyama ◽  
Fumitada Iguchi ◽  
Keiji Yashiro ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Mechanical Testing ◽  
Fracture Strength ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Testing Method ◽  
Reducing Conditions ◽  
In Situ Mechanical Testing ◽  
Electrical Reliability

For the commercialization of solid oxide fuel cell (SOFC), in addition to the electrical reliability, it is also important to ensure the mechanical reliability of SOFC. Thus, the establishment of a suitable mechanical testing method under various temperatures and oxygen partial pressure conditions is a prerequisite for the development of reliable SOFCs. This paper presents the experimental results of the investigation of elastic modulus and fracture strength on the SOFC components under reducing conditions. An in-situ mechanical testing method was developed in order to investigate the elastic modulus and fracture strength of solid oxide fuel cells components under high oxidizing/reducing environments. The elastic modulus was shown to change under reducing condition, and the behavior was most likely due to non-stoichiometry. It was demonstrated that the in-situ mechanical testing method enabled us to estimate the internal stress in the SOFC cell and stack.

Localization simulation of forming-induced residual stresses of composite using prescribed boundary

2021 ◽  
pp. 073168442094118
Author(s):  
Qi Wu ◽  
Hongzhou Zhai ◽  
Nobuhiro Yoshikawa ◽  
Tomotaka Ogasawara ◽  
Naoki Morita
Keyword(s):  
Residual Stresses ◽  
Representative Volume Element ◽  
Computational Cost ◽  
Volume Element ◽  
Thermoplastic Composite ◽  
Structural Deformation ◽  
Element Analysis ◽  
Micro Scale ◽  
Representative Volume ◽  
Localization Approach

A novel localization approach that seamlessly bridges the macro- and micro-scale models is proposed and used to model the forming-induced residual stresses within a representative volume element of a fiber reinforced composite. The approach uses a prescribed boundary that is theoretically deduced by integrating the asymptotic expansion of a composite and the equal strain transfer, thus rendering the simulation setting to be easier than conventional approaches. When the localization approach is used for the finite element analysis, the temperature and residual stresses within an ideal cubic representative volume element are precisely simulated, given a sandwiched thermoplastic composite is formed under one-side cooling condition. The simulation results, after being validated, show that the temperature gradient has an impact on the local residual stresses, especially on the in-plane normal stress transverse to the fiber, and consequently, influences the structural deformation. This newly designed localization approach demonstrates the advantages of enhanced precision and reduced computational cost owing to the fast modeling of the finely meshed representative volume element. This is beneficial for a detailed understanding of the actual residual stresses at the micro-scale.

Loading comparison of two structures in the moving tube of a non-invasive prosthesis

2021 ◽  
pp. 1-9
Author(s):  
Jie Zhang ◽  
Ping Ye ◽  
Lizheng Zhang ◽  
Hongliu Wu ◽  
Tianxi Chi ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Normal Growth ◽  
Limb Length Discrepancy ◽  
The Body ◽  
Lower Limbs ◽  
Lower Body ◽  
Element Analysis ◽  
Non Invasive ◽  
Testing Method ◽  
Finite Element Analysis Simulation

BACKGROUND: The treatment of adolescent patients with distal femoral cancer has always been a concern. The limb-salvage, regarded as a mainstream treatment, had been developed in recent years, but its application in children still remains challenging. This is because it can lead to potential limb-length discrepancy from the continued normal growth of the contralateral lower body. The extendable prosthesis could solve this problem. The principle is that it can artificially control the length of the prosthesis, making it consistent with the length of the side of the lower limbs. However, this prosthesis has some complications. The extendable prosthesis is classified into invasive and minimally invasive, which extends the prosthesis with each operation. OBJECTIVE: We designed a new non-invasive prosthesis that can be extended in the body. Based on the non-invasive and extendable characteristics, we need to verify the supporting performance of this prosthesis. METHODS: We carried out a mechanical testing method and finite element analysis simulation. CONCLUSION: The support performance and non-invasively extension of this prosthesis were verified.

Micro-scale finite element analysis of stress concentrations in steel fiber composites under transverse loading

2014 ◽  
Vol 49 (9) ◽  
pp. 1057-1069 ◽  
Author(s):  
Baris Sabuncuoglu ◽  
Svetlana Orlova ◽  
Larissa Gorbatikh ◽  
Stepan V Lomov ◽  
Ignaas Verpoest
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Steel Fiber ◽  
Fiber Composites ◽  
Transverse Loading ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Micro Scale

Probabilistic Failure Prediction of SCS-6/Ti-15-3 MMC Ring

1993 ◽  
Author(s):  
Frederic A. Holland ◽  
Erwin V. Zaretsky ◽  
Matthew E. Melis
Keyword(s):  
Fatigue Life ◽  
Stress Distribution ◽  
Fracture Strength ◽  
Composite Structures ◽  
Weibull Analysis ◽  
Effective Volume ◽  
Element Analysis ◽  
Simple Method ◽  
Sample Data ◽  
Two Parameter

Abstract Two-parameter Weibull analysis was used to predict the fracture strength and fatigue life of an SCS-6/Ti-15-3 MMC ring from coupon sample data. The fracture strength and fatigue life of the ring were assumed to be volume dependent. The predicted fracture strengths were determined in terms of maximum allowable ring internal pressure. Two methods were used. One simple method was to calculate an effective volume for an idealized ring on the basis of a theoretical solution approximating the stress distribution. The fracture strength and fatigue life of the coupon samples were then scaled to the effective volume of the ring. The other method utilized finite-element analysis to determine a more realistic stress distribution in the actual, geometrically imperfect ring. The total reliability of the ring was then determined by the product of the elemental reliabilities with coupon samples used as a gage. These approaches were compared with experimental fracture strength results. No fatigue data for the ring were available for comparison. Preliminary results indicate that Weibull analysis of coupon samples shows promise in predicting the fracture strength of metal-matrix composite structures.

Finite Element Analysis of Fiber Composite Dental Bridges: The Effect of Length / Depth Ratio and Load Application Method

1999 ◽  
Author(s):  
Michael D. Nowak ◽  
Kim Haser ◽  
A. Jon Goldberg
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanical Testing ◽  
Fiber Composite ◽  
Single Point ◽  
Element Analysis ◽  
Elastic Range ◽  
Single Force ◽  
Range Testing ◽  
Fiber Reinforce

Abstract Work is continuing in the evaluation of orthotropic fiber reinforce composites for use in the construction of dental bridges. Finite Element Analysis (FEA) models were constructed based upon mechanical testing of end clamped specimens center loaded with a metal indenter. Various length / depth specimens were evaluated in the elastic range, with a variety of load magnitudes. Separate FEA models utilized single point loading, distributed loading, and the construction of a model indenter. Deflections at the loading point demonstrated that all models presented similar findings to those seen in mechanical testing. The similarity of results between the single loading point and the indenter FEA models suggest that either is reasonable for elastic range testing. The significantly shorter CPU run times for the single force models suggest that this may be the best means by which to model orthotropic fiber reinforced dental composites in the elastic range.

Sign in / Sign up

Export Citation Format

Share Document